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Override for the tutor's lesson content generation calls. Auto uses the system default (Claude Sonnet 5 for lesson text, Opus 5 for diagrams).

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System default

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Tutoring abilities

Imagine pouring sweet apple juice into a clear cup on a warm afternoon. How do we describe how much juice is inside without guessing?

We use special words to describe how much a container is holding.

When a cup has nothing inside at all, we say it is **empty**.

When liquid fills the cup all the way to the top brim so no more can fit, it is **full**.

<!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;
      -webkit-tap-highlight-color: transparent;
      user-select: none;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: transparent;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      padding: 16px 8px;
    }

    .container {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 20px;
    }

    .cups-row {
      display: flex;
      justify-content: center;
      align-items: flex-end;
      gap: 16px;
      width: 100%;
    }

    .cup-card {
      flex: 1;
      max-width: 160px;
      background: #ffffff;
      border: 2px solid #e6e6e6;
      border-radius: 16px;
      padding: 16px 8px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 12px;
      cursor: pointer;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.04);
      transition: border-color 0.25s ease, box-shadow 0.25s ease;
    }

    .cup-card.active {
      border-color: #ff9233;
      box-shadow: 0 4px 12px rgba(255, 146, 51, 0.2);
    }

    /* Glass Cup Graphic */
    .cup-wrapper {
      position: relative;
      width: 64px;
      height: 110px;
      display: flex;
      justify-content: center;
      align-items: flex-end;
    }

    .cup-glass {
      position: relative;
      width: 100%;
      height: 100%;
      border-left: 3.5px solid #cbd5e1;
      border-right: 3.5px solid #cbd5e1;
      border-bottom: 5px solid #cbd5e1;
      border-top: none;
      border-radius: 0 0 10px 10px;
      background: rgba(241, 245, 249, 0.4);
      overflow: hidden;
      display: flex;
      flex-direction: column;
      justify-content: flex-end;
    }

    /* Guide line for half mark */
    .half-guide {
      position: absolute;
      top: 50%;
      left: 0;
      width: 100%;
      height: 1px;
      border-top: 1.5px dashed #94a3b8;
      pointer-events: none;
      z-index: 2;
      opacity: 0.7;
    }

    /* Liquid styling */
    .liquid {
      width: 100%;
      background: linear-gradient(180deg, #ffaa4d 0%, #ff8c26 100%);
      transition: height 0.4s ease;
      position: relative;
    }

    .liquid-surface {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 4px;
      background: #ffd199;
      opacity: 0.9;
    }

    .card-empty .liquid { height: 0%; }
    .card-half .liquid { height: 50%; }
    .card-full .liquid { height: 100%; }

    .cup-label {
      font-size: 15px;
      font-weight: 700;
      color: #475569;
      text-align: center;
      transition: color 0.25s ease;
    }

    .cup-card.active .cup-label {
      color: #e06d00;
    }

    .badge {
      font-size: 12px;
      font-weight: 600;
      padding: 3px 8px;
      border-radius: 20px;
      background: #f1f5f9;
      color: #64748b;
      transition: background 0.25s ease, color 0.25s ease;
    }

    .cup-card.active .badge {
      background: #ffe8d6;
      color: #d96200;
    }

    @media (max-width: 380px) {
      .cup-wrapper {
        width: 52px;
        height: 96px;
      }
      .cup-label {
        font-size: 13px;
      }
      .badge {
        font-size: 11px;
      }
    }
  </style>
</head>
<body>

  <div class="container">
    <div class="cups-row">
      
      <div class="cup-card card-empty" onclick="select(0)">
        <div class="badge">0%</div>
        <div class="cup-wrapper">
          <div class="half-guide"></div>
          <div class="cup-glass">
            <div class="liquid">
              <div class="liquid-surface"></div>
            </div>
          </div>
        </div>
        <div class="cup-label">Empty</div>
      </div>

      
      <div class="cup-card card-half active" onclick="select(1)">
        <div class="badge">½</div>
        <div class="cup-wrapper">
          <div class="half-guide"></div>
          <div class="cup-glass">
            <div class="liquid">
              <div class="liquid-surface"></div>
            </div>
          </div>
        </div>
        <div class="cup-label">Half-Full</div>
      </div>

      
      <div class="cup-card card-full" onclick="select(2)">
        <div class="badge">100%</div>
        <div class="cup-wrapper">
          <div class="half-guide"></div>
          <div class="cup-glass">
            <div class="liquid">
              <div class="liquid-surface"></div>
            </div>
          </div>
        </div>
        <div class="cup-label">Full</div>
      </div>
    </div>
  </div>

  <script>
    const cards = document.querySelectorAll('.cup-card');

    function select(index) {
      cards.forEach((card, i) => {
        if (i === index) {
          card.classList.add('active');
        } else {
          card.classList.remove('active');
        }
      });
    }
  </script>
</body>
</html>

What happens if you drink some juice until the level drops right to the middle?

When liquid reaches right to the middle of a container, we say it is **half-full**.

The amount of space filled with juice is the exact same size as the empty space left at the top.

<!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>Exploring Full, Half-Full, and Empty</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      padding: 16px;
      user-select: none;
    }

    .main-wrap {
      width: 100%;
      max-width: 440px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 16px;
    }

    /* Button Selector */
    .btn-group {
      display: flex;
      width: 100%;
      gap: 8px;
    }

    .state-btn {
      flex: 1;
      padding: 10px 4px;
      font-size: 14px;
      font-weight: 600;
      background: #ffffff;
      color: #64748b;
      border: 2px solid #e2e8f0;
      border-radius: 12px;
      cursor: pointer;
      transition: all 0.25s ease;
      text-align: center;
    }

    .state-btn.active {
      background: #8b5cf6;
      color: #ffffff;
      border-color: #8b5cf6;
      box-shadow: 0 4px 12px rgba(139, 92, 246, 0.25);
    }

    /* Glass Stage */
    .stage {
      position: relative;
      width: 100%;
      height: 240px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 20px;
    }

    /* Glass Container */
    .glass-outer {
      position: relative;
      width: 130px;
      height: 210px;
      background: #ffffff;
      border: 4px solid #cbd5e1;
      border-top: none;
      border-radius: 0 0 20px 20px;
      overflow: hidden;
      box-shadow: inset 0 -8px 16px rgba(0, 0, 0, 0.03);
    }

    /* Center line marker */
    .mid-line {
      position: absolute;
      top: 50%;
      left: 0;
      right: 0;
      border-top: 2px dashed #94a3b8;
      z-index: 5;
      pointer-events: none;
      opacity: 0.6;
    }

    /* Liquid fill */
    .liquid {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      background: linear-gradient(180deg, #a78bfa 0%, #8b5cf6 100%);
      transition: height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
      height: 50%;
    }

    .liquid-surface {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      height: 6px;
      background: #c4b5fd;
      border-radius: 50%;
      opacity: 0.8;
      transform: translateY(-50%);
    }

    /* Height Comparison Guides */
    .guides {
      position: relative;
      height: 210px;
      width: 110px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      transition: opacity 0.3s ease;
    }

    .guide-zone {
      flex: 1;
      display: flex;
      align-items: center;
      gap: 8px;
      color: #64748b;
      font-size: 13px;
      font-weight: 600;
      transition: opacity 0.3s ease, transform 0.3s ease;
    }

    .guide-zone.top {
      border-left: 3px solid #cbd5e1;
      padding-left: 8px;
      margin-bottom: 2px;
    }

    .guide-zone.bottom {
      border-left: 3px solid #8b5cf6;
      padding-left: 8px;
      margin-top: 2px;
      color: #7c3aed;
    }

    .equal-badge {
      position: absolute;
      top: 50%;
      left: -14px;
      transform: translateY(-50%);
      background: #8b5cf6;
      color: #ffffff;
      font-size: 12px;
      font-weight: 700;
      padding: 3px 8px;
      border-radius: 999px;
      white-space: nowrap;
      box-shadow: 0 2px 6px rgba(139, 92, 246, 0.3);
      transition: opacity 0.3s ease;
    }

    /* Hidden states for guides */
    .guides.hide-top .guide-zone.top {
      opacity: 0;
      transform: translateX(-4px);
    }
    .guides.hide-bottom .guide-zone.bottom {
      opacity: 0;
      transform: translateX(-4px);
    }
    .guides.hide-badge .equal-badge {
      opacity: 0;
      pointer-events: none;
    }
  </style>
</head>
<body>

  <div class="main-wrap">
    
    <div class="btn-group">
      <button class="state-btn" id="btn-empty" onclick="setLevel(0)">Empty</button>
      <button class="state-btn active" id="btn-half" onclick="setLevel(50)">Half-Full</button>
      <button class="state-btn" id="btn-full" onclick="setLevel(100)">Full</button>
    </div>

    
    <div class="stage">
      <div class="glass-outer">
        <div class="mid-line"></div>
        <div class="liquid" id="liquid">
          <div class="liquid-surface" id="surface"></div>
        </div>
      </div>

      
      <div class="guides" id="guides">
        <div class="guide-zone top" id="label-empty">Empty space</div>
        <div class="equal-badge" id="equal-tag">Equal</div>
        <div class="guide-zone bottom" id="label-juice">Juice</div>
      </div>
    </div>
  </div>

  <script>
    const liquid = document.getElementById('liquid');
    const surface = document.getElementById('surface');
    const guides = document.getElementById('guides');
    const btnEmpty = document.getElementById('btn-empty');
    const btnHalf = document.getElementById('btn-half');
    const btnFull = document.getElementById('btn-full');

    function setLevel(pct) {
      // Update liquid height
      liquid.style.height = pct + '%';
      surface.style.display = pct === 0 ? 'none' : 'block';

      // Update button active state
      btnEmpty.classList.toggle('active', pct === 0);
      btnHalf.classList.toggle('active', pct === 50);
      btnFull.classList.toggle('active', pct === 100);

      // Adjust comparison guides
      if (pct === 50) {
        guides.className = 'guides';
      } else if (pct === 0) {
        guides.className = 'guides hide-bottom hide-badge';
      } else if (pct === 100) {
        guides.className = 'guides hide-top hide-badge';
      }
    }

    // Initialize at Half-Full
    setLevel(50);
  </script>
</body>
</html>

What if the cup is not quite at the middle, but close to the top or bottom?

When juice is almost at the top with only a tiny gap left, the glass is **nearly full**.

When you have just a tiny sip left at the bottom, the glass is **nearly empty**.

<!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>
  :root {
    --water: #38bdf8;
    --water-top: #0284c7;
    --glass-border: #94a3b8;
    --active-bg: #f0f9ff;
    --active-border: #0284c7;
  }

  body {
    background: transparent;
    font-family: system-ui, -apple-system, sans-serif;
    color: #1e2945;
    padding: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    min-height: 100%;
    user-select: none;
    -webkit-user-select: none;
  }

  .glasses-grid {
    display: flex;
    justify-content: center;
    align-items: flex-end;
    gap: 8px;
    width: 100%;
    max-width: 600px;
    margin: auto 0;
  }

  .glass-card {
    flex: 1;
    min-width: 54px;
    max-width: 96px;
    display: flex;
    flex-direction: column;
    align-items: center;
    background: #ffffff;
    border: 2px solid transparent;
    border-radius: 12px;
    padding: 10px 4px 8px;
    cursor: pointer;
    transition: transform 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  }

  .glass-card:active {
    background-color: var(--active-bg);
  }

  .glass-card.active {
    border-color: var(--active-border);
    background-color: var(--active-bg);
  }

  .glass {
    position: relative;
    width: 36px;
    height: 90px;
    border: 3px solid var(--glass-border);
    border-top: 1px solid rgba(148, 163, 184, 0.4);
    border-radius: 0 0 8px 8px;
    background: rgba(248, 250, 252, 0.8);
    overflow: hidden;
    display: flex;
    align-items: flex-end;
  }

  .liquid {
    width: 100%;
    background: linear-gradient(180deg, #7dd3fc 0%, var(--water) 100%);
    transition: height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
  }

  .liquid::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--water-top);
    opacity: 0.8;
  }

  .glass-card:not(.has-water) .liquid::after {
    display: none;
  }

  .half-line {
    position: absolute;
    bottom: 50%;
    left: 0;
    right: 0;
    border-bottom: 1px dashed #cbd5e1;
    pointer-events: none;
  }

  .label {
    margin-top: 8px;
    font-size: 11px;
    font-weight: 700;
    text-align: center;
    line-height: 1.2;
    color: #475569;
    min-height: 26px;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .glass-card.active .label {
    color: var(--active-border);
  }

  .stepper {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 12px;
  }

  .btn {
    background: #ffffff;
    border: 1px solid #cbd5e1;
    border-radius: 8px;
    padding: 6px 14px;
    font-size: 13px;
    font-weight: 600;
    color: #1e2945;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
    transition: background 0.15s ease;
  }

  .btn:active {
    background: #f1f5f9;
  }

  @media (min-width: 480px) {
    .glass {
      width: 46px;
      height: 110px;
      border-width: 3px;
    }
    .label {
      font-size: 12px;
    }
    .btn {
      font-size: 14px;
      padding: 8px 18px;
    }
  }
</style>
</head>
<body>

<div class="glasses-grid">
  
  <div class="glass-card active" data-index="0">
    <div class="glass">
      <div class="half-line"></div>
      <div class="liquid" style="height: 0%;"></div>
    </div>
    <div class="label">Empty</div>
  </div>

  
  <div class="glass-card has-water" data-index="1">
    <div class="glass">
      <div class="half-line"></div>
      <div class="liquid" style="height: 15%;"></div>
    </div>
    <div class="label">Nearly<br>Empty</div>
  </div>

  
  <div class="glass-card has-water" data-index="2">
    <div class="glass">
      <div class="half-line"></div>
      <div class="liquid" style="height: 50%;"></div>
    </div>
    <div class="label">Half<br>Full</div>
  </div>

  
  <div class="glass-card has-water" data-index="3">
    <div class="glass">
      <div class="half-line"></div>
      <div class="liquid" style="height: 85%;"></div>
    </div>
    <div class="label">Nearly<br>Full</div>
  </div>

  
  <div class="glass-card has-water" data-index="4">
    <div class="glass">
      <div class="half-line"></div>
      <div class="liquid" style="height: 100%;"></div>
    </div>
    <div class="label">Full</div>
  </div>
</div>

<div class="stepper">
  <button class="btn" id="prevBtn">← Less</button>
  <button class="btn" id="nextBtn">More →</button>
</div>

<script src="{{VENDOR_CDN}}/classace-diagram.js"></script>
<script>
  const cards = $$('.glass-card');
  let currentIdx = 0;

  function selectIndex(idx) {
    currentIdx = (idx + cards.length) % cards.length;
    cards.forEach((card, i) => {
      if (i === currentIdx) {
        card.classList.add('active');
      } else {
        card.classList.remove('active');
      }
    });
  }

  cards.forEach((card, idx) => {
    onTap(card, () => selectIndex(idx));
  });

  onTap($('#prevBtn'), () => selectIndex(currentIdx - 1));
  onTap($('#nextBtn'), () => selectIndex(currentIdx + 1));
</script>
</body>
</html>

Next time you pour a glass of water or finish a bowl of soup, check the level to see which word fits best!

math

Exploring Full, Half-Full, and Empty Containers. Describe containers using the language of capacity: full, nearly full, half-full, nearly empty, and empty.

Early Level / KS1 Maths: What are Capacity and Volume?

Reception & Year 1 Measurement: Introduce Mass and Capacity (Full and Empty)

Primary Maths: Exploring and Describing Capacity with Everyday Containers

At Early Level (P1 / CfE MNU 1-11a), capacity learning is most effective when grounded in concrete, multisensory play and exploration (water trays, sandpits, dry pasta pouring). Teachers should explicitly model the 5-point continuum ('empty', 'nearly empty', 'half-full', 'nearly full', 'full') using clear, straight-sided containers first before introducing irregular shapes to avoid perceptual distortion. Use choral call-and-response, gestural anchors (hands wide apart for full, flat hand at chest for half-full, hands together for empty), and continuous provision role-play (e.g., 'Capacity Cafe') to secure vocabulary mastery.

Exploring Full, Half-Full, and Empty Containers

Empty and Full

Half-Full

Nearly Full and Nearly Empty