<!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="1:1">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px;
      user-select: none;
    }

    /* Controls header */
    .controls {
      display: flex;
      gap: 8px;
      margin-bottom: 6px;
    }
    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 5px;
      transition: background 0.2s, color 0.2s, border-color 0.2s;
    }
    .btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
    }

    /* Main visual stage */
    .stage {
      position: relative;
      width: 100%;
      max-width: 330px;
      height: 250px;
      display: flex;
      justify-content: center;
      align-items: center;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Water transition */
    .water-rect {
      transition: y 0.8s cubic-bezier(0.4, 0, 0.2, 1), height 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .water-surface {
      transition: cy 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    }

    /* Sphere transition */
    .sphere-group {
      transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    }

    /* Level indicators */
    .level-mark {
      transition: opacity 0.4s ease;
      font-size: 11px;
      font-weight: 700;
      fill: #0369a1;
    }

    /* Equation panel */
    .equation-card {
      width: 100%;
      max-width: 330px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 8px 12px;
      text-align: center;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
    }
    .equation-math {
      font-size: 16px;
      font-weight: 700;
      color: #0f172a;
      letter-spacing: -0.2px;
    }
    .equation-math .highlight {
      color: #0284c7;
    }
    .equation-math .sphere-color {
      color: #64748b;
    }
    .takeaway {
      font-size: 12px;
      font-weight: 600;
      color: #059669;
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="btn active" id="btnBefore" onclick="setStep(0)">1. Before Drop</button>
    <button class="btn" id="btnAfter" onclick="setStep(1)">2. Drop Sphere</button>
  </div>

  
  <div class="stage">
    <svg viewBox="0 0 320 240">
      <defs>
        
        <radialGradient id="sphereGrad" cx="35%" cy="35%" r="65%">
          <stop offset="0%" stop-color="#cbd5e1" />
          <stop offset="50%" stop-color="#64748b" />
          <stop offset="100%" stop-color="#334155" />
        </radialGradient>

        
        <linearGradient id="waterGrad" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="0%" stop-color="#38bdf8" stop-opacity="0.75" />
          <stop offset="100%" stop-color="#0284c7" stop-opacity="0.85" />
        </linearGradient>

        
        <linearGradient id="glassGrad" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="0%" stop-color="#ffffff" stop-opacity="0.6" />
          <stop offset="20%" stop-color="#ffffff" stop-opacity="0.1" />
          <stop offset="80%" stop-color="#ffffff" stop-opacity="0" />
          <stop offset="100%" stop-color="#ffffff" stop-opacity="0.4" />
        </linearGradient>
      </defs>

      
      <ellipse cx="120" cy="216" rx="42" ry="10" fill="#e2e8f0" stroke="#94a3b8" stroke-width="2" />

      
      
      <g>
        <rect id="waterRect" class="water-rect" x="85" y="136" width="70" height="80" fill="url(#waterGrad)" />
        <ellipse cx="120" cy="216" rx="35" ry="7" fill="#0284c7" />
        <ellipse id="waterTop" class="water-surface" cx="120" cy="136" rx="35" ry="7" fill="#7dd3fc" stroke="#38bdf8" stroke-width="1" />
      </g>

      
      <path d="M 85 45 L 85 216 A 35 7 0 0 0 155 216 L 155 45" fill="url(#glassGrad)" stroke="#64748b" stroke-width="2.5" fill-opacity="0.3" />
      
      <ellipse cx="120" cy="45" rx="35" ry="7" fill="none" stroke="#64748b" stroke-width="2.5" />

      
      
      
      <g font-size="9" font-weight="600" fill="#64748b" text-anchor="end">
        
        <line x1="85" y1="56" x2="98" y2="56" stroke="#64748b" stroke-width="1.5" />
        <text x="80" y="59">100</text>

        
        <line x1="85" y1="88" x2="95" y2="88" stroke="#64748b" stroke-width="1.5" />
        <text x="80" y="91">80</text>

        
        <line x1="85" y1="104" x2="98" y2="104" stroke="#0284c7" stroke-width="2" />
        <text x="80" y="107" font-weight="700" fill="#0284c7">70</text>

        
        <line x1="85" y1="120" x2="93" y2="120" stroke="#64748b" stroke-width="1" />

        
        <line x1="85" y1="136" x2="98" y2="136" stroke="#0284c7" stroke-width="2" />
        <text x="80" y="139" font-weight="700" fill="#0284c7">50</text>

        
        <line x1="85" y1="152" x2="95" y2="152" stroke="#64748b" stroke-width="1.5" />
        <text x="80" y="155">40</text>

        
        <line x1="85" y1="184" x2="95" y2="184" stroke="#64748b" stroke-width="1.5" />
        <text x="80" y="187">20</text>
      </g>

      
      <g id="riseCallout" style="opacity: 0; transition: opacity 0.5s ease 0.4s;">
        
        <line x1="165" y1="136" x2="165" y2="104" stroke="#0284c7" stroke-width="2.5" marker-end="url(#arrow)" />
        <path d="M 160 136 L 168 136 M 160 104 L 168 104" stroke="#0284c7" stroke-width="2" />
        <text x="174" y="124" font-size="12" font-weight="800" fill="#0284c7">+20 mL</text>
      </g>

      
      
      <g id="sphereGroup" class="sphere-group" transform="translate(0, 0)">
        <circle cx="240" cy="110" r="16" fill="url(#sphereGrad)" filter="drop-shadow(0px 3px 4px rgba(0,0,0,0.15))" />
        
        
        <g id="sphereLabel" style="transition: opacity 0.3s ease;">
          
          <text x="240" y="78" font-size="20" text-anchor="middle">✋</text>
          <rect x="200" y="134" width="80" height="22" rx="6" fill="#f1f5f9" stroke="#cbd5e1" />
          <text x="240" y="149" font-size="11" font-weight="700" fill="#334155" text-anchor="middle">Solid: 20 mL</text>
        </g>
      </g>
    </svg>
  </div>

  
  <div class="equation-card">
    <div class="equation-math" id="eqText">
      Water Level: <span class="highlight">50 mL</span>
    </div>
    <div class="takeaway" id="takeawayText">
      Solid volume displaced in water
    </div>
  </div>

  <script>
    let currentStep = 0;

    function setStep(step) {
      currentStep = step;
      const btnBefore = document.getElementById('btnBefore');
      const btnAfter = document.getElementById('btnAfter');
      const waterRect = document.getElementById('waterRect');
      const waterTop = document.getElementById('waterTop');
      const sphereGroup = document.getElementById('sphereGroup');
      const sphereLabel = document.getElementById('sphereLabel');
      const riseCallout = document.getElementById('riseCallout');
      const eqText = document.getElementById('eqText');
      const takeawayText = document.getElementById('takeawayText');

      if (step === 0) {
        btnBefore.classList.add('active');
        btnAfter.classList.remove('active');

        // Reset cylinder to 50 mL
        waterRect.setAttribute('y', '136');
        waterRect.setAttribute('height', '80');
        waterTop.setAttribute('cy', '136');

        // Move sphere back out
        sphereGroup.setAttribute('transform', 'translate(0, 0)');
        sphereLabel.style.opacity = '1';
        riseCallout.style.opacity = '0';

        // Update text
        eqText.innerHTML = 'Initial Water: <span class="highlight">50 mL</span>';
        takeawayText.textContent = 'Solid volume displaces water';
      } else {
        btnAfter.classList.add('active');
        btnBefore.classList.remove('active');

        // Rise water to 70 mL (32px higher)
        waterRect.setAttribute('y', '104');
        waterRect.setAttribute('height', '112');
        waterTop.setAttribute('cy', '104');

        // Move sphere into water bottom (dx: 120 - 240 = -120, dy: 200 - 110 = 90)
        sphereGroup.setAttribute('transform', 'translate(-120, 90)');
        sphereLabel.style.opacity = '0';
        riseCallout.style.opacity = '1';

        // Update equation
        eqText.innerHTML = '<span class="highlight">70 mL</span> − 50 mL = <span class="sphere-color">20 mL</span>';
        takeawayText.textContent = 'Solid takes up same space everywhere!';
      }
    }
  </script>
</body>
</html>

What Is a Solid? Exploring Shape and Volume

<!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>Solid Particle Model</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px 10px;
    }

    .diagram-area {
      position: relative;
      width: 100%;
      max-width: 480px;
      aspect-ratio: 1.2 / 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Vibration speeds */
    .vibe-normal .particle {
      animation: vibrate 0.4s infinite alternate ease-in-out;
    }
    .vibe-fast .particle {
      animation: vibrate 0.15s infinite alternate ease-in-out;
    }
    .vibe-paused .particle {
      animation: none !important;
    }

    @keyframes vibrate {
      0%   { transform: translate(0, 0); }
      25%  { transform: translate(var(--dx1, 1.2px), var(--dy1, -1px)); }
      50%  { transform: translate(var(--dx2, -1px), var(--dy2, 1.2px)); }
      75%  { transform: translate(var(--dx1, -0.8px), var(--dy1, -0.8px)); }
      100% { transform: translate(var(--dx2, 1px), var(--dy2, 1px)); }
    }

    /* Labels */
    .label-badge {
      font-size: 12px;
      font-weight: 700;
      fill: #1e2945;
    }
    .label-sub {
      font-size: 10px;
      font-weight: 500;
      fill: #64748b;
    }

    /* Controls */
    .controls {
      display: flex;
      gap: 6px;
      background: #f1f5f9;
      padding: 4px;
      border-radius: 24px;
      border: 1px solid #e2e8f0;
      margin-top: 6px;
    }
    .btn {
      border: none;
      background: transparent;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      border-radius: 18px;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, color 0.2s;
    }
    .btn.active {
      background: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.3);
    }
  </style>
</head>
<body>

  <div class="diagram-area">
    <svg id="scene" viewBox="0 0 460 360" class="vibe-normal">
      <defs>
        
        <radialGradient id="sphereGrad" cx="35%" cy="35%" r="65%">
          <stop offset="0%" stop-color="#38bdf8"/>
          <stop offset="55%" stop-color="#0284c7"/>
          <stop offset="100%" stop-color="#0369a1"/>
        </radialGradient>

        
        <linearGradient id="blockGrad" x1="0%" y1="0%" x2="100%" y2="100%">
          <stop offset="0%" stop-color="#f59e0b"/>
          <stop offset="100%" stop-color="#d97706"/>
        </linearGradient>

        
        <filter id="dropShadow" x="-10%" y="-10%" width="130%" height="130%">
          <feDropShadow dx="0" dy="3" stdDeviation="4" flood-opacity="0.1"/>
        </filter>
      </defs>

      
      <polygon points="100,160 215,60 215,300" fill="#f8fafc" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="4,4"/>

      
      <g transform="translate(30, 130)">
        
        <polygon points="0,30 35,10 95,10 60,30" fill="#fbbf24" stroke="#d97706" stroke-width="1.5"/>
        
        <polygon points="60,30 95,10 95,65 60,85" fill="#b45309" stroke="#92400e" stroke-width="1.5"/>
        
        <rect x="0" y="30" width="60" height="55" rx="2" fill="url(#blockGrad)" stroke="#b45309" stroke-width="1.5"/>
        
        
        <circle cx="45" cy="50" r="14" fill="none" stroke="#0284c7" stroke-width="2" stroke-dasharray="2,2"/>
        <text x="30" y="105" text-anchor="middle" font-size="12" font-weight="700" fill="#1e2945">Solid Block</text>
      </g>

      
      <circle cx="330" cy="180" r="120" fill="#ffffff" stroke="#0284c7" stroke-width="4" filter="url(#dropShadow)"/>

      
      <g stroke="#94a3b8" stroke-width="1.5" stroke-linecap="round">
        
        <g id="h-springs"></g>
        
        <g id="v-springs"></g>
      </g>

      
      <g id="particle-grid"></g>

      
      
      <g transform="translate(330, 32)">
        <rect x="-65" y="-12" width="130" height="24" rx="12" fill="#f0f9ff" stroke="#0284c7" stroke-width="1.5"/>
        <text x="0" y="4" text-anchor="middle" class="label-badge">Tightly packed</text>
        <line x1="0" y1="12" x2="0" y2="48" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="2,2"/>
        <circle cx="0" cy="50" r="3" fill="#0284c7"/>
      </g>

      
      <g transform="translate(195, 335)">
        <rect x="-70" y="-12" width="140" height="24" rx="12" fill="#f0fdf4" stroke="#16a34a" stroke-width="1.5"/>
        <text x="0" y="4" text-anchor="middle" class="label-badge" fill="#166534">Vibrating in place</text>
        <path d="M 0,-12 L 40,-60" stroke="#16a34a" stroke-width="1.5" stroke-dasharray="2,2" fill="none"/>
        <circle cx="40" cy="-60" r="3" fill="#16a34a"/>
      </g>
    </svg>
  </div>

  
  <div class="controls">
    <button class="btn" id="btn-pause">⏸ Pause</button>
    <button class="btn active" id="btn-normal">▶ Vibrate</button>
    <button class="btn" id="btn-fast">⚡ Faster</button>
  </div>

  <script>
    const grid = document.getElementById('particle-grid');
    const hSprings = document.getElementById('h-springs');
    const vSprings = document.getElementById('v-springs');
    const scene = document.getElementById('scene');

    const startX = 250;
    const startY = 100;
    const step = 40;
    const radius = 13;

    // Generate springs & 5x5 particles
    for (let r = 0; r < 5; r++) {
      for (let c = 0; c < 5; c++) {
        const cx = startX + c * step;
        const cy = startY + r * step;

        // Horizontal spring
        if (c < 4) {
          const line = document.createElementNS('http://www.w3.org/2000/svg', 'line');
          line.setAttribute('x1', cx);
          line.setAttribute('y1', cy);
          line.setAttribute('x2', cx + step);
          line.setAttribute('y2', cy);
          line.setAttribute('stroke-dasharray', '3,3');
          hSprings.appendChild(line);
        }

        // Vertical spring
        if (r < 4) {
          const line = document.createElementNS('http://www.w3.org/2000/svg', 'line');
          line.setAttribute('x1', cx);
          line.setAttribute('y1', cy);
          line.setAttribute('x2', cx);
          line.setAttribute('y2', cy + step);
          line.setAttribute('stroke-dasharray', '3,3');
          vSprings.appendChild(line);
        }

        // Particle Circle
        const circle = document.createElementNS('http://www.w3.org/2000/svg', 'circle');
        circle.setAttribute('cx', cx);
        circle.setAttribute('cy', cy);
        circle.setAttribute('r', radius);
        circle.setAttribute('fill', 'url(#sphereGrad)');
        circle.classList.add('particle');

        // Give each particle unique subtle vibration angles and delays
        const dx1 = ((r * 3 + c * 7) % 5 - 2) * 0.8;
        const dy1 = ((r * 7 + c * 3) % 5 - 2) * 0.8;
        const dx2 = -dx1;
        const dy2 = -dy1;
        circle.style.setProperty('--dx1', `${dx1}px`);
        circle.style.setProperty('--dy1', `${dy1}px`);
        circle.style.setProperty('--dx2', `${dx2}px`);
        circle.style.setProperty('--dy2', `${dy2}px`);
        circle.style.animationDelay = `${(r + c) * 0.07}s`;

        grid.appendChild(circle);
      }
    }

    // Speed button toggles
    const btnPause = document.getElementById('btn-pause');
    const btnNormal = document.getElementById('btn-normal');
    const btnFast = document.getElementById('btn-fast');

    function setSpeed(mode) {
      scene.classList.remove('vibe-paused', 'vibe-normal', 'vibe-fast');
      scene.classList.add(`vibe-${mode}`);
      btnPause.classList.toggle('active', mode === 'paused');
      btnNormal.classList.toggle('active', mode === 'normal');
      btnFast.classList.toggle('active', mode === 'fast');
    }

    btnPause.addEventListener('click', () => setSpeed('paused'));
    btnNormal.addEventListener('click', () => setSpeed('normal'));
    btnFast.addEventListener('click', () => setSpeed('fast'));
  </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;
      color: #1e2945;
      background: transparent;
      padding: 8px;
      user-select: none;
      -webkit-user-select: none;
    }

    .grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
      max-width: 620px;
      margin: 0 auto;
    }

    @media (max-width: 480px) {
      .grid {
        grid-template-columns: 1fr;
        gap: 12px;
      }
    }

    .panel {
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      cursor: pointer;
      padding: 6px 4px 10px;
      border-radius: 12px;
      background: rgba(248, 250, 252, 0.85);
      transition: background-color 0.2s ease;
    }

    .panel:hover {
      background: #f1f5f9;
    }

    .panel:active {
      background: #e2e8f0;
    }

    .panel-header {
      width: 100%;
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 8px;
      margin-bottom: 6px;
      padding: 0 4px;
    }

    .panel-title {
      font-size: 15px;
      font-weight: 700;
      color: #0f172a;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }

    .interactive-hint {
      font-size: 11px;
      font-weight: 700;
      color: #0369a1;
      background: #e0f2fe;
      padding: 3px 8px;
      border-radius: 999px;
      white-space: nowrap;
      flex-shrink: 0;
      transition: background-color 0.2s ease, color 0.2s ease;
    }

    .panel:hover .interactive-hint {
      background: #bae6fd;
      color: #0284c7;
    }

    .stage {
      width: 100%;
      height: 135px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    .badge {
      margin-top: 8px;
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      padding: 6px 10px;
      font-size: 12.5px;
      font-weight: 600;
      text-align: center;
      color: #334155;
      line-height: 1.35;
      width: 100%;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    }

    .highlight {
      color: #0284c7;
      font-weight: 700;
    }

    /* Sponge animation */
    .sponge {
      transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
      transform-origin: 100px 105px;
    }
    .finger {
      transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
      transform-origin: 100px 30px;
    }
    .squeezed .sponge {
      transform: scale(1.15, 0.55);
    }
    .squeezed .finger {
      transform: translateY(22px);
    }

    /* Magnifier zoom */
    .mag-glass {
      transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
      transform-origin: 145px 70px;
    }
    .zoomed .mag-glass {
      transform: scale(1.12);
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="panel" id="sandPanel" onclick="toggleZoom()" role="button" aria-label="Toggle zoom on sand grains">
      <div class="panel-header">
        <h3 class="panel-title">Poured Sand</h3>
        <span class="interactive-hint" id="sandHint">Tap to Zoom 🔍</span>
      </div>

      <div class="stage">
        <svg viewBox="0 0 200 130">
          
          <line x1="15" y1="106" x2="95" y2="106" stroke="#cbd5e1" stroke-width="2.5" stroke-linecap="round"/>

          
          <rect x="25" y="32" width="60" height="73" rx="6" fill="#f0f9ff" stroke="#94a3b8" stroke-width="2.5"/>
          <path d="M 22 30 L 88 30" stroke="#94a3b8" stroke-width="3" stroke-linecap="round"/>
          <ellipse cx="55" cy="32" rx="30" ry="4" fill="#e0f2fe" stroke="#94a3b8" stroke-width="1.5"/>

          
          <path d="M 27 55 Q 55 58 83 55 L 83 100 Q 83 103 80 103 L 30 103 Q 27 103 27 100 Z" fill="#fcd34d"/>
          
          <circle cx="40" cy="70" r="1.2" fill="#d97706"/>
          <circle cx="65" cy="65" r="1.3" fill="#d97706"/>
          <circle cx="50" cy="85" r="1.2" fill="#d97706"/>
          <circle cx="70" cy="90" r="1" fill="#d97706"/>
          <circle cx="35" cy="95" r="1.1" fill="#d97706"/>

          
          <line x1="55" y1="75" x2="116" y2="44" stroke="#38bdf8" stroke-width="1.5" stroke-dasharray="3,3"/>
          <line x1="55" y1="75" x2="116" y2="96" stroke="#38bdf8" stroke-width="1.5" stroke-dasharray="3,3"/>

          
          <g class="mag-glass">
            
            <line x1="172" y1="94" x2="192" y2="114" stroke="#64748b" stroke-width="7" stroke-linecap="round"/>
            <line x1="172" y1="94" x2="192" y2="114" stroke="#334155" stroke-width="4" stroke-linecap="round"/>

            
            <circle cx="145" cy="70" r="32" fill="#ffffff" stroke="#0284c7" stroke-width="3.5"/>

            
            
            <polygon points="135,53 147,50 144,63 130,60" fill="#f59e0b" stroke="#b45309" stroke-width="1.5"/>
            
            <polygon points="152,66 164,58 168,70 158,76" fill="#fbbf24" stroke="#d97706" stroke-width="1.5"/>
            
            <polygon points="132,71 145,68 149,83 136,86" fill="#f59e0b" stroke="#b45309" stroke-width="1.5"/>
            
            <polygon points="150,48 157,46 155,53 148,52" fill="#fbbf24" stroke="#d97706" stroke-width="1.2"/>

            
            <line x1="135" y1="53" x2="144" y2="63" stroke="#fef3c7" stroke-width="1"/>
            <line x1="132" y1="71" x2="149" y2="83" stroke="#fef3c7" stroke-width="1"/>

            
            <path d="M 124 60 A 24 24 0 0 1 145 46" fill="none" stroke="#bae6fd" stroke-width="2.5" stroke-linecap="round"/>
          </g>
        </svg>
      </div>

      <div class="badge">
        Each tiny grain is a <span class="highlight">rigid solid</span>!
      </div>
    </div>

    
    <div class="panel" id="spongePanel" onclick="toggleSqueeze()" role="button" aria-label="Toggle squeeze on sponge">
      <div class="panel-header">
        <h3 class="panel-title">Squeezed Sponge</h3>
        <span class="interactive-hint" id="squeezeHint">Tap to Squeeze 🖐️</span>
      </div>

      <div class="stage">
        <svg viewBox="0 0 200 130">
          
          <line x1="25" y1="107" x2="175" y2="107" stroke="#94a3b8" stroke-width="3.5" stroke-linecap="round"/>
          <line x1="35" y1="112" x2="165" y2="112" stroke="#e2e8f0" stroke-width="2" stroke-linecap="round"/>

          
          <g class="finger">
            <path d="M 90 0 L 110 0 L 110 32 Q 110 40 100 40 Q 90 40 90 32 Z" fill="#fed7aa" stroke="#ea580c" stroke-width="2"/>
            <rect x="94" y="28" width="12" height="8" rx="3" fill="#ffedd5"/>
            
            <path d="M 75 16 L 75 30 M 71 26 L 75 31 L 79 26" stroke="#ef4444" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"/>
            <path d="M 125 16 L 125 30 M 121 26 L 125 31 L 129 26" stroke="#ef4444" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"/>
          </g>

          
          <g class="sponge">
            <rect x="50" y="55" width="100" height="50" rx="8" fill="#fde047" stroke="#ca8a04" stroke-width="2.5"/>
            
            <circle cx="68" cy="70" r="3.5" fill="#eab308"/>
            <circle cx="95" cy="65" r="4.5" fill="#eab308"/>
            <circle cx="130" cy="72" r="4" fill="#eab308"/>
            <circle cx="80" cy="88" r="4" fill="#eab308"/>
            <circle cx="115" cy="85" r="3.5" fill="#eab308"/>
            <circle cx="138" cy="90" r="2.5" fill="#eab308"/>
            <circle cx="60" cy="85" r="2" fill="#eab308"/>
          </g>
        </svg>
      </div>

      <div class="badge">
        Bends only when force is applied — <span class="highlight">still a solid</span>!
      </div>
    </div>
  </div>

  <script>
    let isZoomed = false;
    let isSqueezed = false;

    function toggleZoom() {
      const p = document.getElementById('sandPanel');
      const hint = document.getElementById('sandHint');
      isZoomed = !isZoomed;
      p.classList.toggle('zoomed', isZoomed);
      hint.textContent = isZoomed ? 'Zoomed In 🔍' : 'Tap to Zoom 🔍';
    }

    function toggleSqueeze() {
      const p = document.getElementById('spongePanel');
      const hint = document.getElementById('squeezeHint');
      isSqueezed = !isSqueezed;
      p.classList.toggle('squeezed', isSqueezed);
      hint.textContent = isSqueezed ? 'Release 🔄' : 'Tap to Squeeze 🖐️';
    }

    // Gentle auto-demonstration interval
    setInterval(() => {
      if (!document.hidden) {
        toggleSqueeze();
      }
    }, 3500);
  </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 {
      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: space-between;
      min-height: 100%;
      padding: 12px;
      user-select: none;
      -webkit-user-select: none;
    }

    .header-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      background: #e0f2fe;
      border: 1px solid #7dd3fc;
      color: #0369a1;
      padding: 6px 14px;
      border-radius: 9999px;
      font-size: 14px;
      font-weight: 700;
      letter-spacing: -0.01em;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    }

    .stage {
      position: relative;
      width: 100%;
      max-width: 380px;
      height: 230px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .stage svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    .controls {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
      max-width: 380px;
    }

    .btn-container {
      background: #ffffff;
      border: 2px solid #e2e8f0;
      color: #475569;
      border-radius: 12px;
      padding: 10px 6px;
      font-size: 13px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, border-color 0.2s, color 0.2s, box-shadow 0.2s;
    }

    .btn-container .icon {
      font-size: 18px;
      line-height: 1;
    }

    .btn-container.active {
      background: #eff6ff;
      border-color: #2563eb;
      color: #1d4ed8;
      box-shadow: 0 2px 6px rgba(37, 99, 235, 0.15);
    }

    #cube {
      transition: transform 0.45s cubic-bezier(0.34, 1.3, 0.64, 1);
      transform-origin: center center;
    }

    .container-shape {
      transition: opacity 0.3s ease, transform 0.3s ease;
    }
  </style>
</head>
<body>

  
  <div class="header-badge">
    <span>Shape: Unchanged!</span>
    <span style="font-weight: 400; opacity: 0.85;">(Fixed Shape)</span>
  </div>

  
  <div class="stage">
    <svg viewBox="0 0 320 220" aria-hidden="true">
      <defs>
        
        <filter id="shadow" x="-20%" y="-20%" width="140%" height="140%">
          <feDropShadow dx="0" dy="4" stdDeviation="3" flood-opacity="0.08" />
        </filter>
        
        <linearGradient id="glassGrad" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="0%" stop-color="#ffffff" stop-opacity="0.6"/>
          <stop offset="20%" stop-color="#cbd5e1" stop-opacity="0.2"/>
          <stop offset="80%" stop-color="#94a3b8" stop-opacity="0.1"/>
          <stop offset="100%" stop-color="#ffffff" stop-opacity="0.5"/>
        </linearGradient>
      </defs>

      
      <line x1="20" y1="195" x2="300" y2="195" stroke="#cbd5e1" stroke-width="2" stroke-linecap="round" />

      
      <g id="v-bowl" class="container-shape">
        
        <ellipse cx="160" cy="195" rx="65" ry="7" fill="#e2e8f0" />
        
        <ellipse cx="160" cy="130" rx="68" ry="12" fill="#f1f5f9" stroke="#cbd5e1" stroke-width="2" />
        
        <path d="M 92 130 C 92 196, 228 196, 228 130 Z" fill="url(#glassGrad)" stroke="#94a3b8" stroke-width="2.5" stroke-linejoin="round" />
        
        <path d="M 92 130 C 92 142, 228 142, 228 130" fill="none" stroke="#64748b" stroke-width="2" opacity="0.6" />
      </g>

      
      <g id="v-vase" class="container-shape" style="opacity: 0; pointer-events: none;">
        
        <ellipse cx="160" cy="195" rx="38" ry="6" fill="#e2e8f0" />
        
        <rect x="126" y="90" width="68" height="105" rx="6" fill="url(#glassGrad)" stroke="#94a3b8" stroke-width="2.5" />
        
        <ellipse cx="160" cy="90" rx="34" ry="7" fill="#f1f5f9" stroke="#94a3b8" stroke-width="2" />
        
        <path d="M 126 90 C 126 97, 194 97, 194 90" fill="none" stroke="#64748b" stroke-width="2" opacity="0.5" />
      </g>

      
      <g id="v-tray" class="container-shape" style="opacity: 0; pointer-events: none;">
        
        <ellipse cx="160" cy="195" rx="100" ry="6" fill="#e2e8f0" />
        
        <polygon points="50,170 70,195 250,195 270,170" fill="url(#glassGrad)" stroke="#94a3b8" stroke-width="2.5" stroke-linejoin="round" />
        
        <polygon points="68,172 82,192 238,192 252,172" fill="#e2e8f0" opacity="0.4" />
      </g>

      
      
      <g id="cube" transform="translate(160, 162)" filter="url(#shadow)">
        
        <polygon points="0,-36 24,-24 0,-12 -24,-24" fill="#60a5fa" />
        
        <polygon points="-24,-24 0,-12 0,16 -24,4" fill="#2563eb" />
        
        <polygon points="0,-12 24,-24 24,4 0,16" fill="#1d4ed8" />
        
        <polyline points="-24,-24 0,-12 24,-24" fill="none" stroke="#93c5fd" stroke-width="1" />
        <line x1="0" y1="-12" x2="0" y2="16" stroke="#1e40af" stroke-width="1" />
      </g>
    </svg>
  </div>

  
  <div class="controls">
    <button class="btn-container active" onclick="selectContainer('bowl')">
      <span class="icon">🥣</span>
      <span>Bowl</span>
    </button>
    <button class="btn-container" onclick="selectContainer('vase')">
      <span class="icon">🏺</span>
      <span>Vase</span>
    </button>
    <button class="btn-container" onclick="selectContainer('tray')">
      <span class="icon">📥</span>
      <span>Tray</span>
    </button>
  </div>

  <script>
    const containers = {
      bowl: { el: document.getElementById('v-bowl'), y: 162 },
      vase: { el: document.getElementById('v-vase'), y: 162 },
      tray: { el: document.getElementById('v-tray'), y: 170 }
    };

    const cube = document.getElementById('cube');
    const buttons = document.querySelectorAll('.btn-container');

    function selectContainer(type) {
      // Update button styles
      buttons.forEach((btn, idx) => {
        const types = ['bowl', 'vase', 'tray'];
        btn.classList.toggle('active', types[idx] === type);
      });

      // Animate Cube: lift up slightly, switch container, drop down
      cube.style.transform = 'translate(160px, 40px)';

      setTimeout(() => {
        // Toggle container visibility
        Object.keys(containers).forEach(key => {
          const item = containers[key];
          if (key === type) {
            item.el.style.opacity = '1';
          } else {
            item.el.style.opacity = '0';
          }
        });

        // Drop cube solidly into selected container
        setTimeout(() => {
          cube.style.transform = `translate(160px, ${containers[type].y}px)`;
        }, 120);
      }, 180);
    }
  </script>
</body>
</html>

science.ks2.y2.t3.s1

Aligned learning resources

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