<!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>Atmospheric Pressure Columns</title>
  <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: #ffffff;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .diagram {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .columns {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }

    .column-wrap {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
    }

    .column-title {
      font-size: 15px;
      font-weight: 700;
      letter-spacing: 0.5px;
      text-transform: uppercase;
    }

    .equator-title {
      color: #ea580c;
    }

    .pole-title {
      color: #0284c7;
    }

    .column {
      position: relative;
      width: 100%;
      height: 220px;
      border-radius: 12px;
      overflow: hidden;
      display: flex;
      justify-content: center;
      border: 1px solid rgba(0, 0, 0, 0.08);
    }

    /* Column Themes */
    .col-equator {
      background: linear-gradient(180deg, #ffedd5 0%, #fed7aa 50%, #fecdd3 100%);
    }

    .col-pole {
      background: linear-gradient(180deg, #e0f2fe 0%, #bae6fd 50%, #dbeafe 100%);
    }

    /* Flow Arrows */
    .flow-arrows {
      position: absolute;
      inset: 0;
      display: flex;
      justify-content: space-around;
      align-items: center;
      padding: 0 10%;
      pointer-events: none;
    }

    .arrow-track {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
      opacity: 0.45;
    }

    .arrow-up {
      font-size: 22px;
      font-weight: 900;
      color: #c2410c;
      animation: floatUp 2.8s ease-in-out infinite;
    }

    .arrow-down {
      font-size: 22px;
      font-weight: 900;
      color: #0369a1;
      animation: floatDown 2.8s ease-in-out infinite;
    }

    @keyframes floatUp {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-8px); }
    }

    @keyframes floatDown {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(8px); }
    }

    /* Air Molecules */
    .particles {
      position: absolute;
      inset: 0;
      width: 100%;
      height: 100%;
    }

    .particle {
      position: absolute;
      width: 9px;
      height: 9px;
      border-radius: 50%;
      transform: translate(-50%, -50%);
    }

    .p-warm {
      background: #ea580c;
      box-shadow: 0 0 4px rgba(234, 88, 12, 0.4);
    }

    .p-cold {
      background: #0284c7;
      box-shadow: 0 0 3px rgba(2, 132, 199, 0.4);
    }

    /* Pressure Plates at Bottom of Column */
    .pressure-plate {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      padding: 8px 4px;
      text-align: center;
      font-weight: 700;
      font-size: 13px;
      background: rgba(255, 255, 255, 0.88);
      backdrop-filter: blur(4px);
      border-top: 1px solid rgba(0, 0, 0, 0.08);
    }

    .plate-low {
      color: #c2410c;
    }

    .plate-high {
      color: #0369a1;
    }

    /* Barometer Scale Section */
    .barometer-scale {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 14px;
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .scale-bar-track {
      position: relative;
      height: 12px;
      border-radius: 6px;
      background: linear-gradient(90deg, #f97316 0%, #38bdf8 100%);
    }

    .scale-labels {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 13px;
      font-weight: 700;
    }

    .val-low {
      color: #c2410c;
    }

    .val-high {
      color: #0369a1;
    }

    .scale-ticks {
      display: flex;
      justify-content: space-between;
      padding: 0 2px;
      font-size: 11px;
      color: #64748b;
      font-weight: 500;
    }
  </style>
</head>
<body>
  <div class="diagram">
    <div class="columns">
      
      <div class="column-wrap">
        <span class="column-title equator-title">Equator</span>
        <div class="column col-equator">
          
          <div class="flow-arrows">
            <div class="arrow-track">
              <span class="arrow-up">↑</span>
              <span class="arrow-up" style="animation-delay: 0.4s;">↑</span>
            </div>
            <div class="arrow-track">
              <span class="arrow-up" style="animation-delay: 0.2s;">↑</span>
              <span class="arrow-up" style="animation-delay: 0.6s;">↑</span>
            </div>
          </div>

          
          <div class="particles">
            <div class="particle p-warm" style="top: 18%; left: 28%;"></div>
            <div class="particle p-warm" style="top: 24%; left: 74%;"></div>
            <div class="particle p-warm" style="top: 36%; left: 45%;"></div>
            <div class="particle p-warm" style="top: 48%; left: 20%;"></div>
            <div class="particle p-warm" style="top: 52%; left: 80%;"></div>
            <div class="particle p-warm" style="top: 66%; left: 36%;"></div>
            <div class="particle p-warm" style="top: 72%; left: 66%;"></div>
          </div>

          <div class="pressure-plate plate-low">
            Surface Low Pressure (L)
          </div>
        </div>
      </div>

      
      <div class="column-wrap">
        <span class="column-title pole-title">Pole</span>
        <div class="column col-pole">
          
          <div class="flow-arrows">
            <div class="arrow-track">
              <span class="arrow-down">↓</span>
              <span class="arrow-down" style="animation-delay: 0.4s;">↓</span>
            </div>
            <div class="arrow-track">
              <span class="arrow-down" style="animation-delay: 0.2s;">↓</span>
              <span class="arrow-down" style="animation-delay: 0.6s;">↓</span>
            </div>
          </div>

          
          <div class="particles">
            <div class="particle p-cold" style="top: 18%; left: 32%;"></div>
            <div class="particle p-cold" style="top: 20%; left: 68%;"></div>
            <div class="particle p-cold" style="top: 32%; left: 48%;"></div>
            <div class="particle p-cold" style="top: 42%; left: 24%;"></div>
            <div class="particle p-cold" style="top: 44%; left: 76%;"></div>
            <div class="particle p-cold" style="top: 54%; left: 40%;"></div>
            <div class="particle p-cold" style="top: 56%; left: 62%;"></div>
            <div class="particle p-cold" style="top: 64%; left: 22%;"></div>
            <div class="particle p-cold" style="top: 66%; left: 80%;"></div>
            <div class="particle p-cold" style="top: 72%; left: 42%;"></div>
            <div class="particle p-cold" style="top: 74%; left: 60%;"></div>
            <div class="particle p-cold" style="top: 78%; left: 28%;"></div>
            <div class="particle p-cold" style="top: 80%; left: 74%;"></div>
          </div>

          <div class="pressure-plate plate-high">
            Surface High Pressure (H)
          </div>
        </div>
      </div>
    </div>

    
    <div class="barometer-scale">
      <div class="scale-labels">
        <span class="val-low">995 mb</span>
        <span style="font-size: 12px; color: #64748b; font-weight: 600;">BAROMETER</span>
        <span class="val-high">1025 mb</span>
      </div>
      <div class="scale-bar-track"></div>
      <div class="scale-ticks">
        <span>Low Pressure</span>
        <span>Standard (1013 mb)</span>
        <span>High Pressure</span>
      </div>
    </div>
  </div>
</body>
</html>

Differential Solar Heating and Pressure Gradients

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Earth Curvature & Sunlight Concentration</title>
  <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;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      min-height: 100vh;
      padding: 12px 14px;
      user-select: none;
      gap: 10px;
    }

    .nav-tabs {
      display: flex;
      gap: 6px;
      background: #e2e8f0;
      padding: 3px;
      border-radius: 12px;
      width: 100%;
      max-width: 440px;
    }

    .tab-btn {
      flex: 1;
      border: none;
      background: transparent;
      padding: 8px 10px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      border-radius: 9px;
      cursor: pointer;
      transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
    }

    .tab-btn.active {
      background: #ffffff;
      color: #0f172a;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
    }

    .stage {
      position: relative;
      width: 100%;
      max-width: 580px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    /* Beam Transitions */
    .beam-group {
      transition: opacity 0.35s ease;
    }
    .beam-group.dimmed {
      opacity: 0.15;
    }

    /* Summary Comparison Cards */
    .info-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
      width: 100%;
      max-width: 580px;
    }

    .info-card {
      background: #ffffff;
      padding: 8px 12px;
      border-radius: 10px;
      border: 1px solid #e2e8f0;
      display: flex;
      flex-direction: column;
      gap: 3px;
      transition: opacity 0.3s ease, border-color 0.3s ease;
    }

    .info-card.hot {
      border-left: 4px solid #ea580c;
    }

    .info-card.cold {
      border-left: 4px solid #0284c7;
    }

    .info-card.dimmed {
      opacity: 0.25;
    }

    .card-title {
      font-size: 12px;
      font-weight: 700;
      display: flex;
      align-items: center;
      gap: 5px;
    }
    .card-title.hot { color: #c2410c; }
    .card-title.cold { color: #0369a1; }

    .card-desc {
      font-size: 11px;
      color: #475569;
      line-height: 1.35;
    }

    @media (max-width: 420px) {
      .tab-btn { font-size: 11px; padding: 7px 4px; }
      .info-grid { grid-template-columns: 1fr; gap: 6px; }
      .card-desc { font-size: 10.5px; }
    }
  </style>
</head>
<body>

  
  <div class="nav-tabs" role="tablist">
    <button class="tab-btn" onclick="setMode('equator')">Equator Beam</button>
    <button class="tab-btn" onclick="setMode('pole')">Polar Beam</button>
    <button class="tab-btn active" onclick="setMode('both')">Compare Both</button>
  </div>

  
  <div class="stage">
    <svg viewBox="0 0 600 300" aria-label="Earth curvature and solar angle diagram">
      <defs>
        
        <linearGradient id="sunbeam-equator" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="0%" stop-color="#fdba74" stop-opacity="0.3"/>
          <stop offset="100%" stop-color="#ea580c" stop-opacity="0.65"/>
        </linearGradient>

        <linearGradient id="sunbeam-pole" x1="0%" y1="0%" x2="100%" y2="0%">
          <stop offset="0%" stop-color="#7dd3fc" stop-opacity="0.3"/>
          <stop offset="100%" stop-color="#0284c7" stop-opacity="0.55"/>
        </linearGradient>

        
        <radialGradient id="earthGrad" cx="65%" cy="48%" r="62%">
          <stop offset="0%" stop-color="#1d4ed8"/>
          <stop offset="45%" stop-color="#1e3a8a"/>
          <stop offset="85%" stop-color="#0f172a"/>
          <stop offset="100%" stop-color="#090d16"/>
        </radialGradient>

        
        <filter id="glow-hot" x="-20%" y="-20%" width="140%" height="140%">
          <feGaussianBlur stdDeviation="3" result="blur"/>
          <feComposite in="SourceGraphic" in2="blur" operator="over"/>
        </filter>
        <filter id="glow-cold" x="-20%" y="-20%" width="140%" height="140%">
          <feGaussianBlur stdDeviation="3" result="blur"/>
          <feComposite in="SourceGraphic" in2="blur" operator="over"/>
        </filter>

        
        <marker id="arrow-eq" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
          <path d="M0,0 L6,3 L0,6 Z" fill="#ea580c" />
        </marker>
        <marker id="arrow-pol" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
          <path d="M0,0 L6,3 L0,6 Z" fill="#0284c7" />
        </marker>
      </defs>

      
      <text x="50" y="22" font-size="11" font-weight="700" fill="#64748b" letter-spacing="0.5">PARALLEL SUNLIGHT RAYS</text>

      
      <circle cx="520" cy="200" r="210" fill="url(#earthGrad)"/>

      
      <circle cx="520" cy="200" r="216" fill="none" stroke="#60a5fa" stroke-width="2.5" opacity="0.35"/>

      
      <path d="M 384 40 A 210 210 0 0 1 520 70" fill="none" stroke="#334155" stroke-width="1" stroke-dasharray="3 3"/>
      
      
      <line x1="310" y1="200" x2="520" y2="200" stroke="#ffffff" stroke-width="1.5" stroke-dasharray="4 3" opacity="0.45"/>
      <rect x="420" y="188" width="84" height="16" rx="4" fill="#0f172a" opacity="0.7"/>
      <text x="462" y="200" font-size="10.5" fill="#e2e8f0" font-weight="600" text-anchor="middle" dominant-baseline="middle">Equator (0°)</text>

      
      <line x1="520" y1="8" x2="520" y2="40" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3 3"/>
      <text x="520" y="24" font-size="10" fill="#cbd5e1" font-weight="700" text-anchor="start" dx="5">North Pole (90°N)</text>

      
      
      
      <g id="polarBeamGroup" class="beam-group">
        
        <polygon points="50,40 384,40 346.3,82 50,82" fill="url(#sunbeam-pole)"/>

        
        <line x1="50" y1="40" x2="380" y2="40" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="5 3"/>
        <line x1="50" y1="61" x2="360" y2="61" stroke="#0284c7" stroke-width="1.5" marker-end="url(#arrow-pol)"/>
        <line x1="50" y1="82" x2="342" y2="82" stroke="#0284c7" stroke-width="1.5" stroke-dasharray="5 3"/>

        
        <path d="M 44,40 L 38,40 L 38,82 L 44,82" fill="none" stroke="#0284c7" stroke-width="1.5"/>
        <text x="32" y="65" font-size="10.5" fill="#0369a1" font-weight="700" text-anchor="end">Width: 1 unit</text>

        
        <path d="M 346.3,82 L 320,82" fill="none" stroke="#38bdf8" stroke-width="1.5" stroke-dasharray="2 2"/>
        <rect x="250" y="55" width="88" height="18" rx="4" fill="#0284c7"/>
        <text x="294" y="67" font-size="10.5" fill="#ffffff" font-weight="700" text-anchor="middle" dominant-baseline="middle">30° Shallow Angle</text>

        
        <path d="M 384 40 A 210 210 0 0 0 346.3 82" fill="none" stroke="#38bdf8" stroke-width="8" stroke-linecap="round" filter="url(#glow-cold)"/>

        
        <path d="M 370,64 Q 400,68 412,82" fill="none" stroke="#7dd3fc" stroke-width="1.5"/>
        <rect x="408" y="74" width="136" height="34" rx="6" fill="#0f172a" stroke="#0284c7" stroke-width="1.5"/>
        <text x="476" y="88" font-size="11" fill="#7dd3fc" font-weight="700" text-anchor="middle">WIDE FOOTPRINT</text>
        <text x="476" y="101" font-size="10" fill="#ffffff" font-weight="600" text-anchor="middle">Diffused Over ~2.0× Area</text>
      </g>

      
      
      
      <g id="equatorBeamGroup" class="beam-group">
        
        <polygon points="50,179 311,179 310,200 311,221 50,221" fill="url(#sunbeam-equator)"/>

        
        <line x1="50" y1="179" x2="307" y2="179" stroke="#ea580c" stroke-width="1.5" stroke-dasharray="5 3"/>
        <line x1="50" y1="200" x2="305" y2="200" stroke="#ea580c" stroke-width="1.5" marker-end="url(#arrow-eq)"/>
        <line x1="50" y1="221" x2="307" y2="221" stroke="#ea580c" stroke-width="1.5" stroke-dasharray="5 3"/>

        
        <path d="M 44,179 L 38,179 L 38,221 L 44,221" fill="none" stroke="#ea580c" stroke-width="1.5"/>
        <text x="32" y="204" font-size="10.5" fill="#c2410c" font-weight="700" text-anchor="end">Width: 1 unit</text>

        
        <rect x="200" y="152" width="94" height="18" rx="4" fill="#ea580c"/>
        <text x="247" y="164" font-size="10.5" fill="#ffffff" font-weight="700" text-anchor="middle" dominant-baseline="middle">90° Direct Angle</text>

        
        <path d="M 302,192 L 302,200 L 310,200" fill="none" stroke="#ea580c" stroke-width="1.5"/>

        
        <path d="M 311 179 A 210 210 0 0 0 311 221" fill="none" stroke="#fb923c" stroke-width="8" stroke-linecap="round" filter="url(#glow-hot)"/>

        
        <path d="M 313,220 Q 330,240 348,248" fill="none" stroke="#fdba74" stroke-width="1.5"/>
        <rect x="348" y="234" width="144" height="34" rx="6" fill="#0f172a" stroke="#ea580c" stroke-width="1.5"/>
        <text x="420" y="248" font-size="11" fill="#fdba74" font-weight="700" text-anchor="middle">TIGHT FOOTPRINT</text>
        <text x="420" y="261" font-size="10" fill="#ffffff" font-weight="600" text-anchor="middle">Concentrated into 1.0× Area</text>
      </g>
    </svg>
  </div>

  
  <div class="info-grid">
    <div id="cardCold" class="info-card cold">
      <div class="card-title cold">
        <span>❄️</span> Polar Beam (Diffused / Cold)
      </div>
      <div class="card-desc">
        Strikes at a shallow <strong>30° angle</strong>. Spreads the identical beam of solar energy over a <strong>wide area</strong>, resulting in lower temperature.
      </div>
    </div>

    <div id="cardHot" class="info-card hot">
      <div class="card-title hot">
        <span>☀️</span> Equator Beam (Concentrated / Hot)
      </div>
      <div class="card-desc">
        Strikes directly at <strong>90°</strong> perpendicular. Concentrates all solar energy into a <strong>tight footprint</strong>, resulting in maximum warmth.
      </div>
    </div>
  </div>

  <script>
    function setMode(mode) {
      const eqBeam = document.getElementById('equatorBeamGroup');
      const polBeam = document.getElementById('polarBeamGroup');
      const cardHot = document.getElementById('cardHot');
      const cardCold = document.getElementById('cardCold');
      const buttons = document.querySelectorAll('.tab-btn');

      buttons.forEach(btn => btn.classList.remove('active'));

      if (mode === 'equator') {
        buttons[0].classList.add('active');
        eqBeam.classList.remove('dimmed');
        polBeam.classList.add('dimmed');
        cardHot.classList.remove('dimmed');
        cardCold.classList.add('dimmed');
      } else if (mode === 'pole') {
        buttons[1].classList.add('active');
        polBeam.classList.remove('dimmed');
        eqBeam.classList.add('dimmed');
        cardCold.classList.remove('dimmed');
        cardHot.classList.add('dimmed');
      } else {
        buttons[2].classList.add('active');
        eqBeam.classList.remove('dimmed');
        polBeam.classList.remove('dimmed');
        cardHot.classList.remove('dimmed');
        cardCold.classList.remove('dimmed');
      }
    }
  </script>
</body>
</html>

OGS.9.ESS.4

Aligned learning resources

Related diagrams