<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <title>Prefix Conversion Solver</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      background: #ffffff;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      min-height: 100%;
    }

    .solver-app {
      width: 100%;
      max-width: 520px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    /* Example selector tabs */
    .tab-group {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
      background: #f1f5f9;
      padding: 4px;
      border-radius: 10px;
    }

    .tab-btn {
      padding: 8px 12px;
      border: 1px solid transparent;
      border-radius: 8px;
      background: transparent;
      color: #64748b;
      font-size: 13px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
    }

    .tab-btn.active {
      background: #ffffff;
      color: #0284c7;
      border-color: #e2e8f0;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    }

    /* Step Stepper Navigation */
    .stepper-nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 6px;
    }

    .step-pills {
      display: flex;
      gap: 6px;
      flex: 1;
    }

    .step-pill {
      flex: 1;
      padding: 6px 4px;
      font-size: 12px;
      font-weight: 700;
      border-radius: 6px;
      border: 1px solid #e2e8f0;
      background: #f8fafc;
      color: #64748b;
      cursor: pointer;
      text-align: center;
      transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
    }

    .step-pill.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
    }

    .nav-btn {
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 700;
      border-radius: 6px;
      border: 1px solid #e2e8f0;
      background: #ffffff;
      color: #1e2945;
      cursor: pointer;
      transition: background 0.15s ease;
    }

    .nav-btn:disabled {
      opacity: 0.35;
      cursor: not-allowed;
    }

    /* Target Question Banner */
    .target-banner {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .target-label {
      font-size: 12px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: #64748b;
    }

    .target-math {
      font-size: 16px;
      font-weight: 700;
      color: #0f172a;
    }

    /* Step Sequence Container */
    .steps-container {
      display: flex;
      flex-direction: column;
      gap: 8px;
      min-height: 220px;
    }

    .step-row {
      display: flex;
      align-items: center;
      gap: 10px;
      padding: 10px 12px;
      border-radius: 8px;
      border: 1px solid #e2e8f0;
      background: #ffffff;
      opacity: 0.3;
      transition: opacity 0.25s ease, background 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
    }

    .step-row.visible {
      opacity: 0.7;
    }

    .step-row.active-step {
      opacity: 1;
      background: #f0f9ff;
      border-color: #38bdf8;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.08);
    }

    .step-num-badge {
      width: 26px;
      height: 26px;
      border-radius: 50%;
      background: #e2e8f0;
      color: #475569;
      font-size: 12px;
      font-weight: 800;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-shrink: 0;
      transition: background 0.2s ease, color 0.2s ease;
    }

    .active-step .step-num-badge {
      background: #0284c7;
      color: #ffffff;
    }

    .step-content {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 2px;
    }

    .step-desc {
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      text-transform: uppercase;
      letter-spacing: 0.3px;
    }

    .active-step .step-desc {
      color: #0284c7;
    }

    .step-formula {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      display: flex;
      align-items: center;
      flex-wrap: wrap;
      gap: 4px;
    }

    .highlight {
      color: #0284c7;
      background: #e0f2fe;
      padding: 1px 5px;
      border-radius: 4px;
    }

    .result-highlight {
      color: #047857;
      background: #d1fae5;
      padding: 2px 6px;
      border-radius: 4px;
      font-weight: 800;
    }
  </style>
</head>
<body>

  <div class="solver-app">
    
    <div class="tab-group">
      <button class="tab-btn active" id="tabEx1" onclick="setExample(0)">
        <span>450 nm → m</span>
      </button>
      <button class="tab-btn" id="tabEx2" onclick="setExample(1)">
        <span>0.008 A → μA</span>
      </button>
    </div>

    
    <div class="stepper-nav">
      <button class="nav-btn" id="prevBtn" onclick="prevStep()">←</button>
      <div class="step-pills">
        <button class="step-pill active" id="pill0" onclick="goToStep(0)">Step 1</button>
        <button class="step-pill" id="pill1" onclick="goToStep(1)">Step 2</button>
        <button class="step-pill" id="pill2" onclick="goToStep(2)">Step 3</button>
      </div>
      <button class="nav-btn" id="nextBtn" onclick="nextStep()">→</button>
    </div>

    
    <div class="target-banner">
      <span class="target-label" id="targetType">Convert</span>
      <span class="target-math" id="targetMath">450 nm → meters</span>
    </div>

    
    <div class="steps-container" id="stepsContainer">
      
      <div class="step-row visible active-step" id="row0">
        <div class="step-num-badge">1</div>
        <div class="step-content">
          <div class="step-desc" id="s1Desc">Prefix Multiplier</div>
          <div class="step-formula" id="s1Formula">
            nano (n) = <span class="highlight">10<sup>-9</sup></span>
          </div>
        </div>
      </div>

      
      <div class="step-row" id="row1">
        <div class="step-num-badge">2</div>
        <div class="step-content">
          <div class="step-desc" id="s2Desc">Direct Substitution</div>
          <div class="step-formula" id="s2Formula">
            450 × <span class="highlight">10<sup>-9</sup></span> m
          </div>
        </div>
      </div>

      
      <div class="step-row" id="row2">
        <div class="step-num-badge">3</div>
        <div class="step-content">
          <div class="step-desc" id="s3Desc">Standard Form</div>
          <div class="step-formula" id="s3Formula">
            = <span class="result-highlight">4.5 × 10<sup>-7</sup> m</span>
          </div>
        </div>
      </div>
    </div>
  </div>

  <script>
    const examples = [
      {
        targetLabel: "Prefix to Base",
        targetMath: "450 nm → meters",
        steps: [
          { desc: "Prefix Multiplier", formula: 'nano (n) = <span class="highlight">10<sup>-9</sup></span>' },
          { desc: "Direct Substitution", formula: '450 × <span class="highlight">10<sup>-9</sup></span> m' },
          { desc: "Standard Form", formula: '= <span class="result-highlight">4.5 × 10<sup>-7</sup> m</span>' }
        ]
      },
      {
        targetLabel: "Base to Prefix",
        targetMath: "0.008 A → microamperes (μA)",
        steps: [
          { desc: "Conversion Factor", formula: 'Base → μ = multiply by <span class="highlight">10<sup>6</sup></span>' },
          { desc: "Multiply", formula: '0.008 × <span class="highlight">1,000,000</span> μA' },
          { desc: "Final Result", formula: '= <span class="result-highlight">8,000 μA</span> (8 × 10<sup>3</sup> μA)' }
        ]
      }
    ];

    let currentEx = 0;
    let currentStep = 0;

    function render() {
      const ex = examples[currentEx];

      // Update Tabs
      document.getElementById('tabEx1').classList.toggle('active', currentEx === 0);
      document.getElementById('tabEx2').classList.toggle('active', currentEx === 1);

      // Update Target Banner
      document.getElementById('targetType').textContent = ex.targetLabel;
      document.getElementById('targetMath').textContent = ex.targetMath;

      // Update Step Data
      for (let i = 0; i < 3; i++) {
        document.getElementById(`s${i + 1}Desc`).textContent = ex.steps[i].desc;
        document.getElementById(`s${i + 1}Formula`).innerHTML = ex.steps[i].formula;

        const row = document.getElementById(`row${i}`);
        const pill = document.getElementById(`pill${i}`);

        // State classes
        const isPastOrCurrent = i <= currentStep;
        const isCurrent = i === currentStep;

        row.classList.toggle('visible', isPastOrCurrent);
        row.classList.toggle('active-step', isCurrent);
        pill.classList.toggle('active', isCurrent);
      }

      // Update Buttons
      document.getElementById('prevBtn').disabled = currentStep === 0;
      document.getElementById('nextBtn').disabled = currentStep === 2;
    }

    function setExample(idx) {
      if (currentEx === idx) return;
      currentEx = idx;
      currentStep = 0;
      render();
    }

    function goToStep(idx) {
      currentStep = idx;
      render();
    }

    function nextStep() {
      if (currentStep < 2) {
        currentStep++;
        render();
      }
    }

    function prevStep() {
      if (currentStep > 0) {
        currentStep--;
        render();
      }
    }

    // Init
    render();
  </script>
</body>
</html>

Prefixes in the SI System: Kilo, Milli, Micro and Nano

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:5">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      color: #1e2945;
      background: transparent;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 8px 4px;
      width: 100%;
      min-height: 100%;
    }
    .diagram-wrap {
      width: 100%;
      max-width: 350px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .ladder-container {
      display: grid;
      grid-template-columns: 32px 1fr 32px;
      gap: 6px;
      align-items: stretch;
    }
    .side-rail {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      border-radius: 8px;
      padding: 6px 2px;
      font-size: 10px;
      font-weight: 700;
      text-align: center;
      line-height: 1.1;
    }
    .rail-left {
      background: #eff6ff;
      border: 1px dashed #93c5fd;
      color: #1d4ed8;
    }
    .rail-right {
      background: #f0fdf4;
      border: 1px dashed #86efac;
      color: #15803d;
    }
    .rail-label {
      writing-mode: vertical-rl;
      transform: rotate(180deg);
      letter-spacing: 0.5px;
      text-transform: uppercase;
      font-size: 9px;
      margin: 4px 0;
    }
    .rail-right .rail-label {
      transform: none;
    }
    .rail-arrow {
      font-size: 14px;
      font-weight: 900;
    }
    .ladder {
      display: flex;
      flex-direction: column;
      gap: 4px;
    }
    .prefix-row {
      display: grid;
      grid-template-columns: 80px 42px 1fr;
      align-items: center;
      padding: 5px 8px;
      background: #ffffff;
      border: 1.5px solid #e6e6e6;
      border-radius: 8px;
      cursor: pointer;
      transition: background 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
      font-size: 12px;
    }
    .prefix-row:hover {
      background: #f8fafc;
      border-color: #cbd5e1;
    }
    .prefix-row.active {
      border-color: #0284c7;
      background: #f0f9ff;
      box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.2);
    }
    .prefix-name {
      font-weight: 700;
      color: #1e2945;
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .prefix-symbol {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 22px;
      height: 22px;
      border-radius: 4px;
      background: #f1f5f9;
      font-family: "Courier New", monospace;
      font-weight: 700;
      font-size: 13px;
      color: #0f172a;
    }
    .prefix-row.active .prefix-symbol {
      background: #0284c7;
      color: #ffffff;
    }
    .prefix-power {
      font-family: "Courier New", monospace;
      font-weight: 700;
      color: #475569;
      font-size: 12px;
      text-align: right;
    }
    .prefix-row.active .prefix-power {
      color: #0369a1;
      font-weight: 800;
    }
    .base-row {
      background: #f8fafc;
      border-style: dashed;
    }
    .info-card {
      height: 72px;
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 10px;
      padding: 8px 12px;
      display: flex;
      flex-direction: column;
      justify-content: center;
      gap: 3px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
    }
    .info-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 13px;
      font-weight: 700;
    }
    .info-title {
      color: #0284c7;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .info-multiplier {
      font-family: "Courier New", monospace;
      font-size: 11px;
      color: #64748b;
      font-weight: 600;
    }
    .info-example {
      font-size: 12px;
      color: #334155;
      display: flex;
      align-items: center;
      gap: 6px;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }
    .info-tag {
      display: inline-block;
      padding: 1px 5px;
      border-radius: 4px;
      background: #f1f5f9;
      font-size: 10px;
      font-weight: 700;
      color: #475569;
      flex-shrink: 0;
    }
  </style>
</head>
<body>
  <div class="diagram-wrap">
    <div class="ladder-container">
      
      <div class="side-rail rail-left" title="Converting to larger prefix: divide by factor">
        <span class="rail-arrow">▲</span>
        <span class="rail-label">Divide ÷ 10ⁿ</span>
        <span class="rail-arrow">▲</span>
      </div>

      
      <div class="ladder" id="ladder">
        <div class="prefix-row" data-idx="0">
          <div class="prefix-name">Mega</div>
          <div class="prefix-symbol">M</div>
          <div class="prefix-power">10⁶</div>
        </div>
        <div class="prefix-row" data-idx="1">
          <div class="prefix-name">Kilo</div>
          <div class="prefix-symbol">k</div>
          <div class="prefix-power">10³</div>
        </div>
        <div class="prefix-row base-row active" data-idx="2">
          <div class="prefix-name">Base</div>
          <div class="prefix-symbol">—</div>
          <div class="prefix-power">10⁰</div>
        </div>
        <div class="prefix-row" data-idx="3">
          <div class="prefix-name">Centi</div>
          <div class="prefix-symbol">c</div>
          <div class="prefix-power">10⁻²</div>
        </div>
        <div class="prefix-row" data-idx="4">
          <div class="prefix-name">Milli</div>
          <div class="prefix-symbol">m</div>
          <div class="prefix-power">10⁻³</div>
        </div>
        <div class="prefix-row" data-idx="5">
          <div class="prefix-name">Micro</div>
          <div class="prefix-symbol">μ</div>
          <div class="prefix-power">10⁻⁶</div>
        </div>
        <div class="prefix-row" data-idx="6">
          <div class="prefix-name">Nano</div>
          <div class="prefix-symbol">n</div>
          <div class="prefix-power">10⁻⁹</div>
        </div>
      </div>

      
      <div class="side-rail rail-right" title="Converting to smaller prefix: multiply by factor">
        <span class="rail-arrow">▼</span>
        <span class="rail-label">Multiply × 10ⁿ</span>
        <span class="rail-arrow">▼</span>
      </div>
    </div>

    
    <div class="info-card" id="infoCard">
      <div class="info-header">
        <span class="info-title" id="infoTitle">Base Unit (10⁰)</span>
        <span class="info-multiplier" id="infoMultiplier">= 1</span>
      </div>
      <div class="info-example" id="infoExample">
        <span class="info-tag">EXAMPLE</span>
        <span id="exampleText">📏 Metre rule / 1 litre bottle</span>
      </div>
    </div>
  </div>

  <script>
    const data = [
      {
        title: "Mega (M = 10⁶)",
        mult: "= 1,000,000",
        tag: "POWER / ENERGY",
        text: "⚡ Power station output (MW)"
      },
      {
        title: "Kilo (k = 10³)",
        mult: "= 1,000",
        tag: "DISTANCE / MASS",
        text: "🏃 5 km run = 5,000 m"
      },
      {
        title: "Base Unit (10⁰)",
        mult: "= 1",
        tag: "STANDARD",
        text: "📏 1 metre (m) / 1 gram (g)"
      },
      {
        title: "Centi (c = 10⁻²)",
        mult: "= 0.01 (1/100)",
        tag: "EVERYDAY",
        text: "✏️ Pencil width = ~1 cm"
      },
      {
        title: "Milli (m = 10⁻³)",
        mult: "= 0.001 (1/1000)",
        tag: "SMALL SCALE",
        text: "🐜 Ant length = ~3 mm"
      },
      {
        title: "Micro (μ = 10⁻⁶)",
        mult: "= 0.000001",
        tag: "MICROSCOPIC",
        text: "🩸 Red blood cell = ~7 μm"
      },
      {
        title: "Nano (n = 10⁻⁹)",
        mult: "= 0.000000001",
        tag: "NANOSCALE",
        text: "🧬 DNA strand width = ~2 nm"
      }
    ];

    const rows = document.querySelectorAll('.prefix-row');
    const infoTitle = document.getElementById('infoTitle');
    const infoMultiplier = document.getElementById('infoMultiplier');
    const infoExample = document.getElementById('infoExample');
    const exampleText = document.getElementById('exampleText');

    function selectPrefix(index) {
      rows.forEach((r, i) => {
        r.classList.toggle('active', i === index);
      });
      const item = data[index];
      infoTitle.textContent = item.title;
      infoMultiplier.textContent = item.mult;
      exampleText.textContent = item.text;
    }

    rows.forEach((row) => {
      row.addEventListener('click', () => {
        const idx = parseInt(row.getAttribute('data-idx'), 10);
        selectPrefix(idx);
      });
    });
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8f9fa;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      min-height: 100%;
    }

    .grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 10px;
      width: 100%;
      flex-grow: 1;
    }

    @media (min-width: 580px) {
      .grid {
        grid-template-columns: repeat(4, 1fr);
      }
    }

    .tool-card {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      text-align: center;
      cursor: pointer;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
      user-select: none;
    }

    .tool-card:hover, .tool-card.active {
      border-color: #22b7ff;
      box-shadow: 0 4px 12px rgba(34, 183, 255, 0.15);
    }

    .tool-card.active {
      background: #f0f9ff;
    }

    .tool-name {
      font-size: 14px;
      font-weight: 700;
      color: #0f172a;
      line-height: 1.2;
      min-height: 34px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .svg-wrap {
      height: 130px;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 6px 0;
    }

    .svg-wrap svg {
      height: 100%;
      max-width: 100%;
      overflow: visible;
    }

    .badge {
      font-size: 11px;
      font-weight: 600;
      padding: 3px 6px;
      border-radius: 6px;
      margin-bottom: 6px;
      line-height: 1.2;
      display: inline-block;
    }

    .badge-beaker   { background: #f1f5f9; color: #475569; }
    .badge-cylinder { background: #e0f2fe; color: #0284c7; }
    .badge-pipette  { background: #ccfbf1; color: #0d9488; }
    .badge-burette  { background: #ede9fe; color: #7c3aed; }

    .resolution-box {
      width: 100%;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      padding: 4px 2px;
    }

    .res-label {
      font-size: 9px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: #64748b;
      font-weight: 600;
    }

    .res-val {
      font-size: 13px;
      font-weight: 700;
      color: #0f172a;
    }

    .precision-bar {
      margin-top: 10px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 6px 12px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-size: 11px;
      font-weight: 600;
      color: #475569;
    }

    .bar-track {
      flex-grow: 1;
      height: 6px;
      background: linear-gradient(90deg, #94a3b8 0%, #38bdf8 40%, #2dd4bf 75%, #a855f7 100%);
      border-radius: 3px;
      margin: 0 10px;
      position: relative;
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="tool-card" id="card-0" onclick="selectTool(0)">
      <div class="tool-name">Beaker</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 80 120" width="70">
          
          <path d="M 12,20 L 12,108 Q 12,114 20,114 L 60,114 Q 68,114 68,108 L 68,20 L 73,15 L 73,12 L 67,12 L 67,20 Z" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linejoin="round"/>
          <path d="M 7,12 L 13,12 L 13,20" stroke="#64748b" stroke-width="2.5" fill="none" stroke-linecap="round"/>
          
          <path d="M 14.5,60 Q 28,58 40,60 T 65.5,60 L 65.5,108 Q 65.5,111.5 60,111.5 L 20,111.5 Q 14.5,111.5 14.5,108 Z" fill="#bae6fd" opacity="0.75"/>
          
          <path d="M 14.5,60 Q 28,56 40,60 T 65.5,60" fill="none" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="3,2"/>
          
          <line x1="15" y1="40" x2="30" y2="40" stroke="#94a3b8" stroke-width="2" stroke-linecap="round"/>
          <line x1="15" y1="65" x2="32" y2="65" stroke="#0369a1" stroke-width="2" stroke-linecap="round"/>
          <line x1="15" y1="90" x2="26" y2="90" stroke="#0369a1" stroke-width="2" stroke-linecap="round"/>
          <text x="35" y="43" font-size="9" fill="#94a3b8" font-family="sans-serif">100</text>
          <text x="36" y="68" font-size="9" fill="#0369a1" font-family="sans-serif">50</text>
        </svg>
      </div>
      <div class="badge badge-beaker">Rough / Heating</div>
      <div class="resolution-box">
        <div class="res-label">Resolution</div>
        <div class="res-val">±5 – 10 mL</div>
      </div>
    </div>

    
    <div class="tool-card" id="card-1" onclick="selectTool(1)">
      <div class="tool-name">Measuring<br>Cylinder</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 80 120" width="70">
          
          <ellipse cx="40" cy="112" rx="26" ry="6" fill="none" stroke="#64748b" stroke-width="2"/>
          
          <path d="M 28,14 L 28,110 M 52,14 L 52,110" stroke="#64748b" stroke-width="2.5"/>
          <path d="M 24,14 L 28,14 M 52,14 L 56,10 L 56,14" stroke="#64748b" stroke-width="2" fill="none"/>
          
          <rect x="29.5" y="45" width="21" height="64" fill="#7dd3fc" opacity="0.75"/>
          <ellipse cx="40" cy="45" rx="10.5" ry="2.5" fill="#38bdf8" stroke="#0284c7" stroke-width="1.5"/>
          
          <line x1="29" y1="28" x2="38" y2="28" stroke="#94a3b8" stroke-width="1.5"/>
          <line x1="29" y1="34" x2="34" y2="34" stroke="#94a3b8" stroke-width="1"/>
          <line x1="29" y1="40" x2="34" y2="40" stroke="#94a3b8" stroke-width="1"/>
          <line x1="29" y1="46" x2="39" y2="46" stroke="#0369a1" stroke-width="1.5"/>
          <line x1="29" y1="52" x2="34" y2="52" stroke="#0369a1" stroke-width="1"/>
          <line x1="29" y1="58" x2="34" y2="58" stroke="#0369a1" stroke-width="1"/>
          <line x1="29" y1="64" x2="38" y2="64" stroke="#0369a1" stroke-width="1.5"/>
          <line x1="29" y1="70" x2="34" y2="70" stroke="#0369a1" stroke-width="1"/>
          <line x1="29" y1="76" x2="34" y2="76" stroke="#0369a1" stroke-width="1"/>
          <line x1="29" y1="82" x2="38" y2="82" stroke="#0369a1" stroke-width="1.5"/>
          <line x1="29" y1="88" x2="34" y2="88" stroke="#0369a1" stroke-width="1"/>
          <line x1="29" y1="94" x2="34" y2="94" stroke="#0369a1" stroke-width="1"/>
          <line x1="29" y1="100" x2="38" y2="100" stroke="#0369a1" stroke-width="1.5"/>
        </svg>
      </div>
      <div class="badge badge-cylinder">General Lab Work</div>
      <div class="resolution-box">
        <div class="res-label">Resolution</div>
        <div class="res-val">±0.5 – 1.0 mL</div>
      </div>
    </div>

    
    <div class="tool-card" id="card-2" onclick="selectTool(2)">
      <div class="tool-name">Volumetric<br>Pipette</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 80 120" width="70">
          
          <path d="M 37,8 L 43,8 
                   L 43,42 
                   C 43,46 52,50 52,60 
                   L 52,72 
                   C 52,82 43,86 43,96 
                   L 41,114 L 39,114 
                   L 37,96 
                   C 37,86 28,82 28,72 
                   L 28,60 
                   C 28,50 37,46 37,42 Z" 
                fill="none" stroke="#64748b" stroke-width="2"/>
          
          <path d="M 38,28 L 42,28 
                   L 42,42 
                   C 42,46 51,50 51,60 
                   L 51,72 
                   C 51,82 42,86 42,96 
                   L 41,113 L 39,113 
                   L 38,96 
                   C 38,86 29,82 29,72 
                   L 29,60 
                   C 29,50 38,46 38,42 Z" 
                fill="#5eead4" opacity="0.75"/>
          
          <line x1="33" y1="28" x2="47" y2="28" stroke="#ef4444" stroke-width="2" stroke-linecap="round"/>
          <text x="50" y="31" font-size="8" font-weight="700" fill="#ef4444" font-family="sans-serif">25</text>
        </svg>
      </div>
      <div class="badge badge-pipette">Exact Single Vol.</div>
      <div class="resolution-box">
        <div class="res-label">Resolution</div>
        <div class="res-val">±0.06 mL</div>
      </div>
    </div>

    
    <div class="tool-card" id="card-3" onclick="selectTool(3)">
      <div class="tool-name">Burette</div>
      <div class="svg-wrap">
        <svg viewBox="0 0 80 120" width="70">
          
          <path d="M 34,8 L 34,92 L 38,96 L 38,102 M 42,102 L 42,96 L 46,92 L 46,8" stroke="#64748b" stroke-width="2" fill="none"/>
          <path d="M 39,106 L 41,106 L 40.5,116 L 39.5,116 Z" fill="#64748b"/>
          
          <rect x="35.5" y="32" width="9" height="61" fill="#c4b5fd" opacity="0.85"/>
          <ellipse cx="40" cy="32" rx="4.5" ry="1.5" fill="#a78bfa" stroke="#7c3aed" stroke-width="1"/>
          
          <line x1="35" y1="16" x2="40" y2="16" stroke="#94a3b8" stroke-width="1.2"/>
          <text x="42" y="18" font-size="6.5" fill="#94a3b8" font-family="sans-serif">0</text>
          <line x1="35" y1="22" x2="38" y2="22" stroke="#94a3b8" stroke-width="0.8"/>
          <line x1="35" y1="27" x2="38" y2="27" stroke="#94a3b8" stroke-width="0.8"/>
          <line x1="35" y1="32" x2="40" y2="32" stroke="#7c3aed" stroke-width="1.2"/>
          <line x1="35" y1="38" x2="38" y2="38" stroke="#7c3aed" stroke-width="0.8"/>
          <line x1="35" y1="44" x2="39" y2="44" stroke="#7c3aed" stroke-width="1"/>
          <line x1="35" y1="50" x2="38" y2="50" stroke="#7c3aed" stroke-width="0.8"/>
          <line x1="35" y1="56" x2="40" y2="56" stroke="#7c3aed" stroke-width="1.2"/>
          <text x="42" y="58" font-size="6.5" fill="#7c3aed" font-family="sans-serif">25</text>
          <line x1="35" y1="62" x2="38" y2="62" stroke="#7c3aed" stroke-width="0.8"/>
          <line x1="35" y1="68" x2="39" y2="68" stroke="#7c3aed" stroke-width="1"/>
          <line x1="35" y1="74" x2="38" y2="74" stroke="#7c3aed" stroke-width="0.8"/>
          <line x1="35" y1="80" x2="40" y2="80" stroke="#7c3aed" stroke-width="1.2"/>
          <text x="42" y="82" font-size="6.5" fill="#7c3aed" font-family="sans-serif">50</text>
          
          <circle cx="40" cy="100" r="3.5" fill="#475569"/>
          <rect x="31" y="98.5" width="18" height="3" rx="1.5" fill="#334155"/>
        </svg>
      </div>
      <div class="badge badge-burette">Titration / Variable</div>
      <div class="resolution-box">
        <div class="res-label">Resolution</div>
        <div class="res-val">±0.05 mL</div>
      </div>
    </div>
  </div>

  
  <div class="precision-bar">
    <span>Low Precision</span>
    <div class="bar-track"></div>
    <span>High Precision</span>
  </div>

  <script>
    function selectTool(index) {
      document.querySelectorAll('.tool-card').forEach((card, idx) => {
        if (idx === index) {
          card.classList.toggle('active');
        } else {
          card.classList.remove('active');
        }
      });
    }
  </script>
</body>
</html>

Selecting Appropriate Measuring Instruments for Volume and Mass

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <title>Reading a Meniscus</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      background: #f8fafc;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 12px;
      user-select: none;
      -webkit-user-select: none;
    }

    .nav-bar {
      display: flex;
      gap: 8px;
      margin-bottom: 8px;
      flex-wrap: wrap;
      justify-content: center;
    }

    .btn-toggle {
      background: #ffffff;
      border: 2px solid #cbd5e1;
      color: #1e2945;
      padding: 6px 14px;
      font-size: 14px;
      font-weight: 600;
      border-radius: 8px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background-color 0.2s, border-color 0.2s, color 0.2s;
    }

    .btn-toggle:hover {
      border-color: #94a3b8;
    }

    .btn-toggle.active {
      background: #1e2945;
      border-color: #1e2945;
      color: #ffffff;
    }

    .btn-toggle.active.correct {
      background: #10b981;
      border-color: #10b981;
      color: #ffffff;
    }

    .svg-wrap {
      width: 100%;
      max-width: 480px;
      height: auto;
    }

    svg {
      width: 100%;
      height: auto;
      display: block;
    }

    .sight-line {
      transition: all 0.35s ease;
    }

    .eye-group {
      transition: transform 0.35s ease;
    }

    .reading-badge {
      font-size: 14px;
      font-weight: 700;
      transition: fill 0.3s ease;
    }
  </style>
</head>
<body>

  <div class="nav-bar">
    <button class="btn-toggle" id="btn-high" onclick="setView('high')">Too High ↗</button>
    <button class="btn-toggle active correct" id="btn-level" onclick="setView('level')">Eye Level 👁</button>
    <button class="btn-toggle" id="btn-low" onclick="setView('low')">Too Low ↘</button>
  </div>

  <div class="svg-wrap">
    <svg viewBox="0 0 460 330" aria-label="Burette meniscus measurement">
      <defs>
        
        <linearGradient id="liquidGrad" x1="0" y1="0" x2="1" y2="0">
          <stop offset="0%" stop-color="#bae6fd" stop-opacity="0.85"/>
          <stop offset="50%" stop-color="#e0f2fe" stop-opacity="0.6"/>
          <stop offset="100%" stop-color="#7dd3fc" stop-opacity="0.9"/>
        </linearGradient>
        
        <linearGradient id="glassGrad" x1="0" y1="0" x2="1" y2="0">
          <stop offset="0%" stop-color="#64748b" stop-opacity="0.25"/>
          <stop offset="15%" stop-color="#ffffff" stop-opacity="0.6"/>
          <stop offset="85%" stop-color="#ffffff" stop-opacity="0.1"/>
          <stop offset="100%" stop-color="#64748b" stop-opacity="0.3"/>
        </linearGradient>
      </defs>

      
      <g transform="translate(10, 24)">
        <text x="0" y="0" font-size="12" font-weight="700" fill="#64748b">0.00 mL (Top)</text>
        <path d="M 40,6 L 40,24 M 36,20 L 40,26 L 44,20" fill="none" stroke="#94a3b8" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"/>
        <text x="0" y="38" font-size="11" font-weight="600" fill="#64748b">Scale increases ↓</text>
      </g>

      
      <rect x="130" y="15" width="80" height="300" rx="4" fill="#f1f5f9" stroke="#94a3b8" stroke-width="2.5"/>
      <rect x="130" y="15" width="80" height="300" rx="4" fill="url(#glassGrad)"/>

      
      
      <path d="M 130,135 Q 170,165 210,135 L 210,315 L 130,315 Z" fill="url(#liquidGrad)"/>
      <path d="M 130,135 Q 170,165 210,135" fill="none" stroke="#0284c7" stroke-width="3" stroke-linecap="round"/>

      
      <circle cx="170" cy="165" r="3.5" fill="#0369a1"/>

      
      
      
      
      <g stroke="#334155" stroke-linecap="round">
        
        <line x1="130" y1="69" x2="146" y2="69" stroke-width="1.5"/>
        <line x1="130" y1="81" x2="139" y2="81" stroke-width="1"/>
        <line x1="130" y1="93" x2="139" y2="93" stroke-width="1"/>
        <line x1="130" y1="105" x2="139" y2="105" stroke-width="1"/>
        <line x1="130" y1="117" x2="139" y2="117" stroke-width="1"/>

        
        <line x1="130" y1="129" x2="152" y2="129" stroke-width="2"/>
        <text x="122" y="133" font-size="12" font-weight="700" text-anchor="end" fill="#1e2945" stroke="none">24</text>

        
        <line x1="130" y1="141" x2="139" y2="141" stroke-width="1"/>
        <line x1="130" y1="153" x2="139" y2="153" stroke-width="1"/>
        <line x1="130" y1="165" x2="148" y2="165" stroke-width="1.8"/> 
        <line x1="130" y1="177" x2="139" y2="177" stroke-width="1"/>

        
        <line x1="130" y1="189" x2="146" y2="189" stroke-width="1.5"/>
        <line x1="130" y1="201" x2="139" y2="201" stroke-width="1"/>
        <line x1="130" y1="213" x2="139" y2="213" stroke-width="1"/>
        <line x1="130" y1="225" x2="139" y2="225" stroke-width="1"/>
        <line x1="130" y1="237" x2="139" y2="237" stroke-width="1"/>

        
        <line x1="130" y1="249" x2="152" y2="249" stroke-width="2"/>
        <text x="122" y="253" font-size="12" font-weight="700" text-anchor="end" fill="#1e2945" stroke="none">25</text>

        
        <line x1="130" y1="261" x2="139" y2="261" stroke-width="1"/>
        <line x1="130" y1="273" x2="139" y2="273" stroke-width="1"/>
        <line x1="130" y1="285" x2="146" y2="285" stroke-width="1.5"/>
      </g>

      
      <line id="sightLine" class="sight-line"
            x1="126" y1="165" x2="368" y2="165"
            stroke="#10b981" stroke-width="2.5" stroke-dasharray="none"/>

      
      <circle id="scaleMarker" cx="130" cy="165" r="4.5" fill="#10b981" class="sight-line"/>

      
      <g id="eyeGroup" class="eye-group" transform="translate(375, 165)">
        
        <path d="M 0,-14 Q 22,0 44,-14 Q 22,-28 0,-14 Z" fill="#ffffff" stroke="#1e2945" stroke-width="2"/>
        
        <circle cx="16" cy="-14" r="6" fill="#1e2945"/>
        <circle cx="14" cy="-16" r="2" fill="#ffffff"/>
        
        <path d="M 8,-23 L 6,-28 M 22,-26 L 22,-32 M 36,-23 L 38,-28" stroke="#1e2945" stroke-width="1.5" stroke-linecap="round"/>
      </g>

      
      <g id="resultCard" transform="translate(235, 270)">
        <rect x="0" y="0" width="210" height="48" rx="8" fill="#ffffff" stroke="#10b981" stroke-width="2" id="cardBorder"/>
        <text x="14" y="22" font-size="12" font-weight="600" fill="#64748b">Reading:</text>
        <text x="14" y="40" font-size="15" font-weight="800" fill="#10b981" id="readingVal">24.30 mL ✓ Correct</text>
      </g>
    </svg>
  </div>

  <script>
    const configs = {
      high: {
        eyeY: 75,
        targetY: 138, // apparent line on left scale
        color: '#ef4444',
        dash: '5,5',
        reading: '24.08 mL ✗ Parallax Error',
        btnId: 'btn-high'
      },
      level: {
        eyeY: 165,
        targetY: 165,
        color: '#10b981',
        dash: 'none',
        reading: '24.30 mL ✓ Correct (Bottom)',
        btnId: 'btn-level'
      },
      low: {
        eyeY: 255,
        targetY: 192,
        color: '#ef4444',
        dash: '5,5',
        reading: '24.52 mL ✗ Parallax Error',
        btnId: 'btn-low'
      }
    };

    function setView(view) {
      const cfg = configs[view];

      // Update buttons
      ['btn-high', 'btn-level', 'btn-low'].forEach(id => {
        const b = document.getElementById(id);
        b.classList.remove('active', 'correct');
      });
      const activeBtn = document.getElementById(cfg.btnId);
      activeBtn.classList.add('active');
      if (view === 'level') activeBtn.classList.add('correct');

      // Update SVG elements
      const sightLine = document.getElementById('sightLine');
      const scaleMarker = document.getElementById('scaleMarker');
      const eyeGroup = document.getElementById('eyeGroup');
      const readingVal = document.getElementById('readingVal');
      const cardBorder = document.getElementById('cardBorder');

      // Sight line endpoints: touches left scale (x=130, cfg.targetY) through meniscus bottom (170, 165) to eye (375, cfg.eyeY)
      sightLine.setAttribute('x1', '130');
      sightLine.setAttribute('y1', cfg.targetY);
      sightLine.setAttribute('x2', '375');
      sightLine.setAttribute('y2', cfg.eyeY);
      sightLine.setAttribute('stroke', cfg.color);
      sightLine.setAttribute('stroke-dasharray', cfg.dash);

      scaleMarker.setAttribute('cy', cfg.targetY);
      scaleMarker.setAttribute('fill', cfg.color);

      eyeGroup.setAttribute('transform', `translate(375, ${cfg.eyeY})`);

      readingVal.textContent = cfg.reading;
      readingVal.setAttribute('fill', cfg.color);
      cardBorder.setAttribute('stroke', cfg.color);
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      background: #f8f9fa;
      color: #1e2945;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 14px 10px;
      min-height: 100vh;
      user-select: none;
    }
    .wrapper {
      width: 100%;
      max-width: 600px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }
    .header {
      text-align: center;
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.3;
    }
    .subtitle {
      font-size: 12px;
      color: #64748b;
      text-align: center;
      margin-top: -6px;
    }
    .instruments-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 8px;
      width: 100%;
      align-items: end;
      margin-top: 4px;
    }
    .instrument-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-end;
      position: relative;
    }
    .svg-container {
      width: 100%;
      height: 170px;
      display: flex;
      justify-content: center;
      align-items: flex-end;
      position: relative;
    }
    svg {
      overflow: visible;
      max-height: 100%;
      width: auto;
    }
    .liquid-base {
      fill: #38bdf8;
      transition: all 0.4s ease;
    }
    .liquid-added {
      fill: #0ea5e9;
      transition: opacity 0.4s ease;
      opacity: 0;
    }
    .liquid-added.active {
      opacity: 0.95;
    }
    .glass-outline {
      stroke: #64748b;
      stroke-width: 1.5;
      fill: rgba(255, 255, 255, 0.55);
    }
    .tick {
      stroke: #94a3b8;
      stroke-width: 1;
    }
    .delta-arrow {
      stroke: #e11d48;
      stroke-width: 1.5;
      stroke-dasharray: 2, 2;
      opacity: 0;
      transition: opacity 0.35s ease;
    }
    .delta-arrow.active {
      opacity: 1;
    }
    .delta-text {
      fill: #e11d48;
      font-size: 10px;
      font-weight: 700;
      opacity: 0;
      transition: opacity 0.35s ease;
      text-anchor: start;
    }
    .delta-text.active {
      opacity: 1;
    }
    .card-label {
      width: 100%;
      text-align: center;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      padding: 6px 3px;
      margin-top: 6px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      min-height: 52px;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    .inst-name {
      font-size: 11px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
    }
    .inst-unc {
      font-size: 10.5px;
      font-weight: 600;
      color: #0284c7;
      margin-top: 2px;
      line-height: 1.15;
    }
    .inst-sub {
      font-size: 9.5px;
      font-weight: 500;
      color: #64748b;
      display: block;
    }
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      width: 100%;
      margin-top: 4px;
    }
    .btn {
      background: #0ea5e9;
      color: #ffffff;
      border: none;
      padding: 8px 20px;
      font-size: 13px;
      font-weight: 600;
      border-radius: 20px;
      cursor: pointer;
      box-shadow: 0 2px 4px rgba(14, 165, 233, 0.25);
      transition: background-color 0.2s, box-shadow 0.2s;
    }
    .btn:hover {
      background: #0284c7;
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      background: #e2e8f0;
      color: #334155;
      box-shadow: none;
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    .btn.reset:hover {
      background: #cbd5e1;
    }

    @media (max-width: 420px) {
      .instruments-grid {
        gap: 4px;
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      .inst-name {
        font-size: 10px;
      }
      .inst-unc {
        font-size: 9.5px;
      }
      .inst-sub {
        font-size: 8.5px;
      }
      .delta-text {
        font-size: 9px;
      }
    }
  </style>
</head>
<body>

  <div class="wrapper">
    <div class="header">Effect of +1 mL on Liquid Height (&Delta;<i>h</i>)</div>
    <div class="subtitle">Narrower glass cross-section &rarr; Greater height change &rarr; Higher sensitivity</div>

    <div class="instruments-grid">
      
      <div class="instrument-col">
        <div class="svg-container">
          <svg width="74" height="150" viewBox="0 0 74 150">
            <defs>
              <clipPath id="beaker-clip">
                <path d="M 6 10 L 6 138 Q 6 144 12 144 L 62 144 Q 68 144 68 138 L 68 10 Z" />
              </clipPath>
            </defs>
            
            <path d="M 3 10 L 6 10 L 6 138 Q 6 144 12 144 L 62 144 Q 68 144 68 138 L 68 10 L 71 10" class="glass-outline" />
            
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              <rect id="beaker-add" x="0" y="78" width="74" height="2" class="liquid-added" />
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            <line x1="6" y1="40" x2="16" y2="40" class="tick" />
            <line x1="6" y1="60" x2="14" y2="60" class="tick" />
            <line x1="6" y1="80" x2="16" y2="80" class="tick" />
            <line x1="6" y1="100" x2="14" y2="100" class="tick" />
            <line x1="6" y1="120" x2="16" y2="120" class="tick" />
            
            <line x1="69" y1="80" x2="69" y2="78" class="delta-arrow" />
            <text x="70" y="75" class="delta-text">~0.2 mm</text>
          </svg>
        </div>
        <div class="card-label">
          <div class="inst-name">Beaker</div>
          <div class="inst-unc">~±5%</div>
        </div>
      </div>

      
      <div class="instrument-col">
        <div class="svg-container">
          <svg width="60" height="160" viewBox="0 0 60 160">
            <defs>
              <clipPath id="cyl-clip">
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              </clipPath>
            </defs>
            
            <path d="M 10 148 L 50 148 L 43 140 L 17 140 Z" fill="#cbd5e1" stroke="#64748b" stroke-width="1.5" />
            
            <path d="M 14 15 L 17 15 L 17 140 L 43 140 L 43 15 L 46 15" class="glass-outline" />
            
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              <rect id="cyl-add" x="17" y="75" width="26" height="10" class="liquid-added" />
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            <line x1="17" y1="35" x2="25" y2="35" class="tick" />
            <line x1="17" y1="55" x2="22" y2="55" class="tick" />
            <line x1="17" y1="75" x2="25" y2="75" class="tick" />
            <line x1="17" y1="95" x2="22" y2="95" class="tick" />
            <line x1="17" y1="115" x2="25" y2="115" class="tick" />
            
            <line x1="45" y1="85" x2="45" y2="75" class="delta-arrow" />
            <text x="46" y="73" class="delta-text">+3 mm</text>
          </svg>
        </div>
        <div class="card-label">
          <div class="inst-name">Cylinder</div>
          <div class="inst-unc">±0.5 mL</div>
        </div>
      </div>

      
      <div class="instrument-col">
        <div class="svg-container">
          <svg width="60" height="165" viewBox="0 0 60 165">
            <defs>
              <clipPath id="pipette-clip">
                <path d="M 26 5 L 26 65 Q 26 72 17 85 Q 15 95 17 105 Q 26 118 26 125 L 27 155 L 33 155 L 34 125 Q 34 118 43 105 Q 45 95 43 85 Q 34 72 34 65 L 34 5 Z" />
              </clipPath>
            </defs>
            
            <path d="M 26 5 L 26 65 Q 26 72 17 85 Q 15 95 17 105 Q 26 118 26 125 L 27 155 L 33 155 L 34 125 Q 34 118 43 105 Q 45 95 43 85 Q 34 72 34 5 Z" class="glass-outline" />
            
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              <rect x="10" y="62" width="40" height="100" class="liquid-base" />
              <rect id="pip-add" x="26" y="22" width="8" height="40" class="liquid-added" />
            </g>
            
            <line x1="24" y1="62" x2="36" y2="62" stroke="#0ea5e9" stroke-width="1.5" />
            
            <line x1="36" y1="62" x2="36" y2="22" class="delta-arrow" />
            <text x="38" y="20" class="delta-text">+25 mm</text>
          </svg>
        </div>
        <div class="card-label">
          <div class="inst-name">Pipette</div>
          <div class="inst-unc">±0.06 mL <span class="inst-sub">(fixed)</span></div>
        </div>
      </div>

      
      <div class="instrument-col">
        <div class="svg-container">
          <svg width="60" height="165" viewBox="0 0 60 165">
            <defs>
              <clipPath id="burette-clip">
                <path d="M 24 5 L 24 135 L 28 143 L 28 158 L 32 158 L 32 143 L 36 135 L 36 5 Z" />
              </clipPath>
            </defs>
            
            <path d="M 24 5 L 24 135 L 28 143 L 28 158 L 32 158 L 32 143 L 36 135 L 36 5 Z" class="glass-outline" />
            
            <rect x="21" y="141" width="18" height="4" rx="2" fill="#64748b" />
            
            <g clip-path="url(#burette-clip)">
              <rect x="20" y="65" width="20" height="95" class="liquid-base" />
              <rect id="bur-add" x="20" y="35" width="20" height="30" class="liquid-added" />
            </g>
            
            <line x1="24" y1="20" x2="30" y2="20" class="tick" />
            <line x1="24" y1="35" x2="33" y2="35" class="tick" />
            <line x1="24" y1="50" x2="30" y2="50" class="tick" />
            <line x1="24" y1="65" x2="33" y2="65" class="tick" />
            <line x1="24" y1="80" x2="30" y2="80" class="tick" />
            <line x1="24" y1="95" x2="33" y2="95" class="tick" />
            
            <line x1="38" y1="65" x2="38" y2="35" class="delta-arrow" />
            <text x="40" y="33" class="delta-text">+18 mm</text>
          </svg>
        </div>
        <div class="card-label">
          <div class="inst-name">Burette</div>
          <div class="inst-unc">±0.05 mL <span class="inst-sub">(variable)</span></div>
        </div>
      </div>
    </div>

    <div class="controls">
      <button id="toggleBtn" class="btn">Add +1 mL Liquid</button>
    </div>
  </div>

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        btn.classList.remove('reset');
      }
    }

    btn.addEventListener('click', () => {
      added = !added;
      updateState();
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  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Fair Testing in Chemical Rates: Compromised vs Controlled</title>
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    .tabs {
      display: flex;
      gap: 4px;
      background: #e2e8f0;
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      font-size: 12px;
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      padding: 5px 10px;
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      bottom: 24px;
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      right: 6px;
      background: rgba(186, 230, 253, 0.25);
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      top: -11px;
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      background: #0284c7;
      color: #ffffff;
      font-size: 10px;
      font-weight: 700;
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      white-space: nowrap;
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      letter-spacing: 0.2px;
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    .beaker-wrap {
      display: flex;
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      align-items: center;
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    .temp-tag {
      font-size: 11px;
      font-weight: 700;
      padding: 2px 6px;
      border-radius: 4px;
      margin-bottom: 5px;
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    .temp-20 { background: #f1f5f9; color: #475569; border: 1px solid #cbd5e1; }
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      height: 78px;
      border: 2px solid #64748b;
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      box-shadow: inset 0 -2px 4px rgba(0,0,0,0.03);
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    .liquid {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 56px;
      border-top: 1.5px solid #94a3b8;
    }
    .conc-1 { background: #e0f2fe; }
    .conc-2 { background: #bae6fd; }

    .mg-strip {
      position: absolute;
      bottom: 3px;
      left: 50%;
      transform: translateX(-50%);
      width: 7px;
      height: 26px;
      background: #64748b;
      border-radius: 1px;
      border: 1px solid #475569;
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    .conc-label {
      font-size: 11px;
      font-weight: 700;
      color: #334155;
      margin-top: 5px;
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      font-size: 11px;
      font-weight: 500;
      padding: 8px 10px;
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      border: 1px solid #fecaca;
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      background: #f0fdf4;
      color: #166534;
      border: 1px solid #bbf7d0;
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      background: rgba(255, 255, 255, 0.95);
      border: 1px solid #64748b;
      border-radius: 50%;
      opacity: 0;
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    .reacting .fast-2 { width: 6px; height: 6px; left: 28px; bottom: 12px; animation: rise 0.5s infinite ease-in 0.15s; }
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    .reacting .fair-slow-1 { width: 4px; height: 4px; left: 24px; bottom: 10px; animation: rise 1.5s infinite ease-in; }
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    .reacting .fair-fast-1 { width: 5px; height: 5px; left: 20px; bottom: 10px; animation: rise 0.9s infinite ease-in; }
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    @keyframes rise {
      0% { opacity: 0; transform: translateY(0); }
      30% { opacity: 0.9; }
      100% { opacity: 0; transform: translateY(-36px); }
    }
  </style>
</head>
<body>

  <div class="header-controls">
    <div class="tabs">
      <button class="tab active" id="tabAll">Both Views</button>
      <button class="tab" id="tabFlawed">Compromised</button>
      <button class="tab" id="tabFair">Fair Test</button>
    </div>
    <button class="btn" id="reactBtn">▶ Add Magnesium & React</button>
  </div>

  <div class="grid">
    
    <div class="card-panel" id="panelFlawed">
      <div class="panel-title bad">✕ Compromised Investigation</div>
      <div class="env-indicator flawed">⚠️ Uncontrolled Variable: Temperature</div>
      
      <div class="beakers-row">
        
        <div class="beaker-wrap">
          <div class="temp-tag temp-20">20°C</div>
          <div class="beaker">
            <div class="liquid conc-1">
              <div class="mg-strip"></div>
              <div class="bubble slow-1"></div>
              <div class="bubble slow-2"></div>
            </div>
          </div>
          <div class="conc-label">0.5 M HCl</div>
        </div>

        
        <div class="beaker-wrap">
          <div class="temp-tag temp-50">50°C ⚠️</div>
          <div class="beaker">
            <div class="liquid conc-2">
              <div class="mg-strip"></div>
              <div class="bubble fast-1"></div>
              <div class="bubble fast-2"></div>
              <div class="bubble fast-3"></div>
              <div class="bubble fast-4"></div>
            </div>
          </div>
          <div class="conc-label">1.0 M HCl</div>
        </div>
      </div>

      <div class="status-badge badge-bad">
        <strong>Uncontrolled Confounding Variable</strong>
        Cannot prove concentration caused speed increase.
      </div>
    </div>

    
    <div class="card-panel" id="panelFair">
      <div class="panel-title good">✓ Controlled Fair Test</div>
      <div class="env-indicator fair">✓ Controlled Variable: Constant Temp</div>

      <div class="beakers-row">
        
        <div class="water-bath-bg">
          <div class="bath-tag-badge">Thermostatted Water Bath (25°C)</div>
        </div>

        
        <div class="beaker-wrap">
          <div class="temp-tag temp-25">25°C</div>
          <div class="beaker">
            <div class="liquid conc-1">
              <div class="mg-strip"></div>
              <div class="bubble fair-slow-1"></div>
              <div class="bubble fair-slow-2"></div>
            </div>
          </div>
          <div class="conc-label">0.5 M HCl</div>
        </div>

        
        <div class="beaker-wrap">
          <div class="temp-tag temp-25">25°C</div>
          <div class="beaker">
            <div class="liquid conc-2">
              <div class="mg-strip"></div>
              <div class="bubble fair-fast-1"></div>
              <div class="bubble fair-fast-2"></div>
              <div class="bubble fair-fast-3"></div>
            </div>
          </div>
          <div class="conc-label">1.0 M HCl</div>
        </div>
      </div>

      <div class="status-badge badge-good">
        <strong>Valid Fair Test</strong>
        Constant 25°C guarantees only concentration changes rate.
      </div>
    </div>
  </div>

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</body>
</html>

Identifying Weaknesses in Experimental Methodology

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
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    .graph-title {
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      margin-bottom: 6px;
      text-align: center;
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    .graph-title.bad { color: #dc2626; }
    .graph-title.good { color: #059669; }

    svg {
      width: 100%;
      height: auto;
      overflow: visible;
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    .axis { stroke: #94a3b8; stroke-width: 1.5; stroke-linecap: round; }
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      stroke: #dc2626;
      stroke-width: 2.5;
      stroke-linejoin: round;
    }

    .line-fine {
      fill: none;
      stroke: #059669;
      stroke-width: 2.5;
      stroke-linejoin: round;
    }

    .true-ghost {
      fill: none;
      stroke: #94a3b8;
      stroke-width: 1.5;
      stroke-dasharray: 4, 4;
    }

    .point-bad { fill: #dc2626; stroke: #fff; stroke-width: 1.5; }
    .point-good { fill: #059669; stroke: #fff; stroke-width: 1.5; }
    .point-optimum { fill: #2563eb; stroke: #fff; stroke-width: 2; }

    /* Smooth, gentle animations without flicker */
    .missed-line {
      stroke: #dc2626;
      stroke-width: 1.5;
      stroke-dasharray: 3, 3;
      animation: pulseDash 3s ease-in-out infinite;
    }

    .missed-badge {
      animation: floatBadge 3s ease-in-out infinite;
    }

    @keyframes pulseDash {
      0%, 100% { opacity: 0.45; }
      50% { opacity: 1; }
    }

    @keyframes floatBadge {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-2px); }
    }

    @media (max-width: 360px) {
      .graph-title { font-size: 13px; }
      .tick-text { font-size: 9px; }
      .axis-label { font-size: 9.5px; }
    }
  </style>
</head>
<body>

  <div class="graphs-container">
    
    <div class="graph-pane">
      <div class="graph-title bad">Graph A: 20°C Intervals (Wide)</div>
      <svg viewBox="0 0 250 180" aria-label="Graph A: 20 degree Celsius intervals missing optimum rate">
        
        <line x1="32" y1="145" x2="235" y2="145" class="axis" />
        <line x1="32" y1="145" x2="32" y2="20" class="axis" />

        
        <text x="135" y="172" text-anchor="middle" class="axis-label">Temperature (°C)</text>
        <text x="12" y="82" text-anchor="middle" transform="rotate(-90 12 82)" class="axis-label">Rate</text>

        
        <text x="32" y="158" text-anchor="middle" class="tick-text">0</text>
        <text x="96.6" y="158" text-anchor="middle" class="tick-text">20</text>
        <text x="161.3" y="158" text-anchor="middle" class="tick-text">40</text>
        <text x="226" y="158" text-anchor="middle" class="tick-text">60</text>

        
        <path d="M 32 141 C 80 137, 130 115, 151.7 28 C 160 55, 172 135, 193.7 145" class="true-ghost" />

        
        <polyline points="32,141 96.6,122 161.3,73 226,145" class="line-coarse" />

        
        <circle cx="32" cy="141" r="3.5" class="point-bad" />
        <circle cx="96.6" cy="122" r="3.5" class="point-bad" />
        <circle cx="161.3" cy="73" r="3.5" class="point-bad" />
        <circle cx="226" cy="145" r="3.5" class="point-bad" />

        
        <circle cx="151.7" cy="28" r="3.5" fill="#94a3b8" stroke="#fff" stroke-width="1" />

        
        <line x1="151.7" y1="28" x2="151.7" y2="82" class="missed-line" />
        
        <g class="missed-badge">
          <rect x="75" y="44" width="122" height="20" rx="4" fill="#fee2e2" stroke="#dc2626" stroke-width="1" />
          <text x="136" y="58" text-anchor="middle" font-size="9.5" font-weight="700" fill="#dc2626">True optimum missed!</text>
        </g>
      </svg>
    </div>

    
    <div class="graph-pane">
      <div class="graph-title good">Graph B: 5°C Intervals (Narrow)</div>
      <svg viewBox="0 0 250 180" aria-label="Graph B: 5 degree Celsius intervals showing true optimum peak">
        
        <line x1="32" y1="145" x2="235" y2="145" class="axis" />
        <line x1="32" y1="145" x2="32" y2="20" class="axis" />

        
        <text x="135" y="172" text-anchor="middle" class="axis-label">Temperature (°C)</text>
        <text x="12" y="82" text-anchor="middle" transform="rotate(-90 12 82)" class="axis-label">Rate</text>

        
        <text x="32" y="158" text-anchor="middle" class="tick-text">0</text>
        <text x="96.6" y="158" text-anchor="middle" class="tick-text">20</text>
        <text x="161.3" y="158" text-anchor="middle" class="tick-text">40</text>
        <text x="226" y="158" text-anchor="middle" class="tick-text">60</text>

        
        <line x1="151.7" y1="28" x2="151.7" y2="145" stroke="#93c5fd" stroke-width="1" stroke-dasharray="2,2" />

        
        <path d="M 32 141 C 80 137, 130 115, 151.7 28 C 160 55, 172 135, 193.7 145 L 226 145" class="line-fine" />

        
        <circle cx="96.6" cy="122" r="2.5" class="point-good" />
        <circle cx="112.8" cy="108" r="2.5" class="point-good" />
        <circle cx="129.0" cy="85" r="2.5" class="point-good" />
        <circle cx="145.1" cy="46" r="2.5" class="point-good" />
        <circle cx="161.3" cy="73" r="2.5" class="point-good" />
        <circle cx="177.5" cy="128" r="2.5" class="point-good" />
        <circle cx="193.7" cy="145" r="2.5" class="point-good" />

        
        <circle cx="151.7" cy="28" r="4.5" class="point-optimum" />

        
        <rect x="90" y="15" width="86" height="18" rx="4" fill="#eff6ff" stroke="#2563eb" stroke-width="1" />
        <text x="133" y="27.5" text-anchor="middle" font-size="9.5" font-weight="700" fill="#1d4ed8">Optimum: 37°C</text>
      </svg>
    </div>
  </div>

</body>
</html>

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<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
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      font-weight: 900;
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      top: 50%;
      left: 50%;
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      flex-direction: column;
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      border: 1px solid #86efac;
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      border: 1px solid #e2e8f0;
      border-radius: 8px;
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      gap: 6px;
      font-size: 13px;
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    .formula {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      font-weight: 600;
      color: #334155;
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    .fraction {
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      flex-direction: column;
      align-items: center;
      vertical-align: middle;
      font-size: 11px;
      line-height: 1.1;
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    .fraction .num {
      border-bottom: 1.5px solid #334155;
      padding: 0 4px 1px;
    }
    .fraction .den {
      padding: 1px 4px 0;
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    .highlight-mean {
      background: #22c55e;
      color: #ffffff;
      padding: 3px 8px;
      border-radius: 5px;
      font-weight: 700;
      font-size: 12px;
    }
  </style>
</head>
<body>

  <div class="grid-container">
    
    <div class="panel">
      <div class="badge badge-bad">⚠️ Sample size <i>n</i> = 1</div>
      
      <div class="scene">
        <div class="single-plant">
          🥀
          <span class="subtext">Seed defect</span>
        </div>
      </div>

      <div class="outcome outcome-bad">
        Misleading: "Drug kills plants"
      </div>
    </div>

    
    <div class="panel">
      <div class="badge badge-good">✓ Sample size <i>n</i> = 10 (×3 repeats)</div>
      
      <div class="scene">
        <div class="pot-grid">
          <div class="plant-item">🌱<span class="subtext">8.4</span></div>
          <div class="plant-item">🌱<span class="subtext">8.5</span></div>
          <div class="plant-item">🌱<span class="subtext">8.3</span></div>
          <div class="plant-item">🌱<span class="subtext">8.4</span></div>
          <div class="plant-item">🌱<span class="subtext">8.6</span></div>
          <div class="plant-item">🌱<span class="subtext">8.3</span></div>
          <div class="plant-item">🌱<span class="subtext">8.5</span></div>
          <div class="plant-item">🌱<span class="subtext">8.4</span></div>
          <div class="plant-item">🌱<span class="subtext">8.2</span></div>
          <div class="plant-item anomaly">🥀<span class="subtext">0.0</span></div>
        </div>
      </div>

      <div class="outcome outcome-good">
        Anomaly excluded • Reliable mean
      </div>
    </div>
  </div>

  
  <div class="formula-bar">
    <div class="formula">
      <span>Mean =</span>
      <div class="fraction">
        <span class="num">Sum of concordant values</span>
        <span class="den">Number of trials (9)</span>
      </div>
    </div>
    <div class="highlight-mean">Mean = 8.4 cm</div>
  </div>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
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      color: #1e293b;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      min-height: 100%;
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      border: 1px solid #e2e8f0;
      border-radius: 10px;
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      font-weight: 700;
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      background: #ffffff;
      padding: 8px 6px;
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      font-size: 12px;
      font-weight: 600;
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      color: #0f172a;
      border-color: #cbd5e1;
      background: #f1f5f9;
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      width: 8px;
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      border-radius: 50%;
      flex-shrink: 0;
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      padding: 10px;
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      flex-direction: column;
      gap: 6px;
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    .panel-flaw {
      background: #fff5f5;
      border: 1px solid #fed7d7;
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      background: #f0fdf4;
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      font-size: 11px;
      font-weight: 700;
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      display: flex;
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    .panel-flaw .panel-label { color: #dc2626; }
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      font-size: 13px;
      line-height: 1.4;
      color: #334155;
      font-weight: 500;
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    .visual-pill {
      margin-top: auto;
      background: #ffffff;
      border-radius: 6px;
      padding: 6px 8px;
      font-size: 11px;
      font-weight: 600;
      color: #475569;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      border: 1px dashed #cbd5e1;
    }

    @media (max-width: 480px) {
      .comparison-grid {
        grid-template-columns: 1fr;
      }
      .breakdown-box {
        min-height: auto;
      }
      .panel-text {
        font-size: 12px;
      }
    }
  </style>
</head>
<body>

  
  <div class="method-card">
    <div class="method-title">Student's Experimental Method</div>
    <span>"To test enzyme activity, I </span>
    <span class="pin pin-amber" id="pin-1" data-flaw="1">🫧 counted bubbles</span>
    <span> produced at </span>
    <span class="pin pin-red" id="pin-0" data-flaw="0">🌡️ 20°C and 40°C</span>
    <span>, testing </span>
    <span class="pin pin-purple" id="pin-2" data-flaw="2">⏱️ once per temperature</span>
    <span>."</span>
  </div>

  
  <div class="nav-tabs">
    <button class="tab-btn active" id="tab-0">
      <span class="dot-badge dot-red"></span> Temp Range
    </button>
    <button class="tab-btn" id="tab-1">
      <span class="dot-badge dot-amber"></span> Bubbles
    </button>
    <button class="tab-btn" id="tab-2">
      <span class="dot-badge dot-purple"></span> Repeats
    </button>
  </div>

  
  <div class="breakdown-box">
    <div class="comparison-grid">
      
      <div class="panel-flaw">
        <div class="panel-label">✕ Flaw</div>
        <div class="panel-text" id="flaw-desc">Only 2 data points; cannot determine trend or optimum temperature.</div>
        <div class="visual-pill" id="flaw-vis">⚠️ 2 Points: 20°C &amp; 40°C</div>
      </div>

      
      <div class="panel-fix">
        <div class="panel-label">✓ Fix</div>
        <div class="panel-text" id="fix-desc">Test 5+ temperatures in 5°C intervals (10°C to 50°C).</div>
        <div class="visual-pill" id="fix-vis">📈 10, 15, 20, 25, 30... 50°C</div>
      </div>
    </div>
  </div>

  <script>
    const flawData = [
      {
        flaw: "Inadequate range & interval (2 data points; cannot find optimum).",
        flawVis: "⚠️ Only 2 points (20°C & 40°C)",
        fix: "Test at least 5 temperatures in 5°C intervals from 10°C to 50°C.",
        fixVis: "📈 10°, 15°, 20°, 25°, 30°... 50°C"
      },
      {
        flaw: "Bubbles vary in volume (imprecise dependent variable).",
        flawVis: "🫧 Uneven bubble sizes",
        fix: "Collect gas in an inverted measuring cylinder or gas syringe.",
        fixVis: "🧪 Measured Gas Volume (cm³)"
      },
      {
        flaw: "Single trial (no repeats to identify anomalies or calculate mean).",
        flawVis: "⚠️ 1 Trial per temp",
        fix: "Perform at least 3 repeats per temperature and calculate a mean.",
        fixVis: "📊 3 Repeats + Mean (x̄)"
      }
    ];

    let currentIdx = 0;

    function setFlaw(index) {
      currentIdx = index;
      const data = flawData[index];

      // Update text
      document.getElementById('flaw-desc').textContent = data.flaw;
      document.getElementById('flaw-vis').textContent = data.flawVis;
      document.getElementById('fix-desc').textContent = data.fix;
      document.getElementById('fix-vis').textContent = data.fixVis;

      // Update active tabs and pins
      for (let i = 0; i < 3; i++) {
        document.getElementById(`tab-${i}`).classList.toggle('active', i === index);
        document.getElementById(`pin-${i}`).classList.toggle('active', i === index);
      }
    }

    // Bind tabs
    for (let i = 0; i < 3; i++) {
      document.getElementById(`tab-${i}`).addEventListener('click', () => setFlaw(i));
      document.getElementById(`pin-${i}`).addEventListener('click', () => setFlaw(i));
    }

    // Initialize first state
    setFlaw(0);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
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      padding: 0;
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      background: #f8f9fa;
      color: #1e2945;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
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      display: flex;
      flex-direction: column;
      gap: 12px;
      width: 100%;
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    .grid {
      display: grid;
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    .tile {
      background: #ffffff;
      border: 1px solid #e2e8f0;
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      gap: 8px;
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    .tile-title {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
      min-height: 34px;
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      align-items: center;
      justify-content: center;
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    .visual-box {
      width: 100%;
      height: 110px;
      background: #f8fafc;
      border-radius: 8px;
      border: 1px solid #edf2f7;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      overflow: hidden;
    }

    .badge {
      font-size: 12px;
      font-weight: 600;
      padding: 5px 8px;
      border-radius: 6px;
      line-height: 1.2;
      width: 100%;
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    .badge-red {
      background: #fee2e2;
      color: #b91c1c;
      border: 1px solid #fecaca;
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    .badge-amber {
      background: #fef3c7;
      color: #b45309;
      border: 1px solid #fde68a;
    }

    .badge-teal {
      background: #ccfbf1;
      color: #0f766e;
      border: 1px solid #99f6e4;
    }

    /* SVG Styling */
    svg {
      display: block;
      width: 100%;
      height: 100%;
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<body>

  <div class="grid">
    
    <div class="tile">
      <div class="tile-title">Uncontrolled<br>Variables</div>
      <div class="visual-box">
        <svg viewBox="0 0 160 110">
          
          <line x1="80" y1="45" x2="80" y2="92" stroke="#94a3b8" stroke-width="4" stroke-linecap="round" />
          <path d="M 55 92 L 105 92" stroke="#94a3b8" stroke-width="4" stroke-linecap="round" />
          <polygon points="80,45 74,56 86,56" fill="#64748b" />
          
          
          
          <line x1="25" y1="33" x2="135" y2="57" stroke="#475569" stroke-width="3" stroke-linecap="round" />
          
          
          <line x1="25" y1="33" x2="15" y2="58" stroke="#cbd5e1" stroke-width="1.5" />
          <line x1="25" y1="33" x2="35" y2="58" stroke="#cbd5e1" stroke-width="1.5" />
          <path d="M 12 58 Q 25 64 38 58" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />
          
          <rect x="20" y="47" width="10" height="10" rx="2" fill="#3b82f6" />
          <text x="25" y="55" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">IV</text>

          
          <line x1="135" y1="57" x2="125" y2="82" stroke="#cbd5e1" stroke-width="1.5" />
          <line x1="135" y1="57" x2="145" y2="82" stroke="#cbd5e1" stroke-width="1.5" />
          <path d="M 122 82 Q 135 88 148 82" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />
          
          <rect x="127" y="71" width="10" height="10" rx="2" fill="#3b82f6" />
          <text x="132" y="79" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">IV</text>
          
          <rect x="138" y="69" width="8" height="12" rx="2" fill="#ef4444" stroke="#b91c1c" stroke-width="1" stroke-dasharray="2,1" />
          <text x="142" y="78" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">?</text>
        </svg>
      </div>
      <div class="badge badge-red">Destroys<br>Validity</div>
    </div>

    
    <div class="tile">
      <div class="tile-title">Inadequate<br>Intervals</div>
      <div class="visual-box">
        <svg viewBox="0 0 160 110">
          
          <line x1="22" y1="90" x2="145" y2="90" stroke="#cbd5e1" stroke-width="2" />
          <line x1="22" y1="90" x2="22" y2="18" stroke="#cbd5e1" stroke-width="2" />
          
          
          
          <path d="M 30 80 Q 80 10 135 80" fill="none" stroke="#f59e0b" stroke-width="2" stroke-dasharray="3,3" opacity="0.85" />
          
          
          <circle cx="80" cy="27.5" r="3.5" fill="#f59e0b" />
          <text x="80" y="19" font-size="9" font-weight="700" fill="#d97706" text-anchor="middle">Peak?</text>

          
          <polyline points="30,80 82.5,78 135,80" fill="none" stroke="#1e2945" stroke-width="2" />
          
          
          <circle cx="30" cy="80" r="4.5" fill="#1e2945" />
          <circle cx="82.5" cy="78" r="4.5" fill="#1e2945" />
          <circle cx="135" cy="80" r="4.5" fill="#1e2945" />
        </svg>
      </div>
      <div class="badge badge-amber">Misses Trends<br>& Optima</div>
    </div>

    
    <div class="tile">
      <div class="tile-title">Insufficient<br>Sample Size</div>
      <div class="visual-box">
        <svg viewBox="0 0 160 110">
          
          <line x1="68" y1="15" x2="68" y2="95" stroke="#e2e8f0" stroke-width="1.5" stroke-dasharray="3,3" />

          
          <text x="35" y="24" font-size="11" font-weight="700" fill="#ef4444" text-anchor="middle">N = 1</text>
          
          <rect x="27" y="32" width="16" height="42" rx="8" fill="#ffffff" stroke="#ef4444" stroke-width="2" />
          
          <path d="M 29 54 Q 35 52 41 54 L 41 66 A 6 6 0 0 1 29 66 Z" fill="#fee2e2" />
          <text x="35" y="93" font-size="13" font-weight="bold" fill="#ef4444" text-anchor="middle">?</text>

          
          <text x="114" y="24" font-size="11" font-weight="700" fill="#0d9488" text-anchor="middle">N = 5</text>
          
          
          
          <rect x="76" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 77.5 52 L 84.5 52 L 84.5 65 A 3.5 3.5 0 0 1 77.5 65 Z" fill="#ccfbf1" />

          
          <rect x="91" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 92.5 51 L 99.5 51 L 99.5 65 A 3.5 3.5 0 0 1 92.5 65 Z" fill="#ccfbf1" />

          
          <rect x="106" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 107.5 58 L 114.5 58 L 114.5 65 A 3.5 3.5 0 0 1 107.5 65 Z" fill="#ccfbf1" />

          
          <rect x="121" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 122.5 52 L 129.5 52 L 129.5 65 A 3.5 3.5 0 0 1 122.5 65 Z" fill="#ccfbf1" />

          
          <rect x="136" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 137.5 53 L 144.5 53 L 144.5 65 A 3.5 3.5 0 0 1 137.5 65 Z" fill="#ccfbf1" />

          <text x="114" y="93" font-size="12" font-weight="bold" fill="#0d9488" text-anchor="middle">✓ Mean</text>
        </svg>
      </div>
      <div class="badge badge-teal">Allows Anomalies<br>to Skew Results</div>
    </div>
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</html>

UK-GCSE-SCIENCE-WS-2

Child standards (7)

Aligned learning resources

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