Advanced

Tutor model

i62 💰:9.4

i52 💰:7.9

🏆 i67 💰:62.5

i70 💰:125.0

i68 💰:125.0

🏆 i66 💰:75.0

i65 💰:125.0

i63 💰:62.5

i61 💰:75.0

i60 💰:9.4

i60 💰:37.5

i58 💰:62.5

i57 💰:22.5

i57 💰:37.5

i56 💰:45.0

⚡ i55 💰:11.25

i55 💰:37.5

i54 💰:62.5

i52 💰:35.0

i51 💰:37.5

i49 💰:15.0

i49 💰:62.5

i48 💰:11.3

i47 💰:7.5

i44 💰:25.0

i43 💰:37.5

i42 💰:187.5

i40 💰:5.0

i39 💰:100.0

i38 💰:37.5

i37 💰:11.0

i36 💰:187.5

i34 💰:12.5

i33 💰:37.5

i30 💰:1.0

i29 💰:1.5

i28 💰:150.0

i23 💰:20.0

i20 💰:4.0

i18 💰:1.0

i16 💰:25.0

i13 💰:1.5

Keep session private

What would you like to learn?

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

Lesson generation model

System default

i58 💰:18.8

i31 💰:11.0

i25 💰:31.3

Tutoring abilities

When you stretch a rubber band, drop an apple, or light a match, where does the energy actually go?

In physics, energy is not a physical liquid or substance—it is a calculated property of a **system** (any object or collection of objects you choose to study) that tells us how much work it can do.

GCSE physics classifies all stored energy into exactly **eight primary energy stores**.

How do we group these eight stores to make them instantly recognizable in any exam problem?

## The Mechanical Stores: Motion and Position

The first three stores depend on how whole objects move, stretch, or change position in a gravitational field.

The **Kinetic Energy Store** ($E_k$) is the energy held by any moving object, given by $E_k = \frac{1}{2}mv^2$, where $m$ is mass and $v$ is velocity.

The **Gravitational Potential Energy Store** ($E_p$) is energy stored when an object is raised in a gravitational field, calculated as $E_p = mgh$, where $g$ is gravitational field strength and $h$ is height change.

The **Elastic Potential Energy Store** ($E_e$) is stored in materials that are temporarily stretched, compressed, or distorted from their equilibrium shape, given by $E_e = \frac{1}{2}ke^2$ (where $k$ is spring constant and $e$ is extension).

The **Elastic Potential Energy Store** ($E_e$) is energy stored in materials that are temporarily stretched, compressed, or distorted from their equilibrium shape, given by $E_e = \frac{1}{2}ke^2$ (where $k$ is spring constant and $e$ is extension).

<!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: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8f9fa;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      padding: 16px;
    }

    .app-wrap {
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .visual-box {
      background: #ffffff;
      border-radius: 12px;
      padding: 16px;
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
      position: relative;
    }

    svg {
      width: 100%;
      height: 150px;
      display: block;
    }

    .spring-path {
      fill: none;
      stroke: #22b7ff;
      stroke-width: 4;
      stroke-linecap: round;
      stroke-linejoin: round;
      transition: d 0.2s ease-out;
    }

    .ref-line {
      stroke: #94a3b8;
      stroke-dasharray: 4 4;
      stroke-width: 1.5;
    }

    .extension-line {
      stroke: #f59e0b;
      stroke-width: 2;
    }

    .metric-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
    }

    .card-tile {
      background: #ffffff;
      border-radius: 12px;
      padding: 12px 14px;
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .tile-label {
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }

    .tile-val {
      font-size: 20px;
      font-weight: 700;
      color: #1e2945;
    }

    .bar-bg {
      height: 8px;
      background: #e2e8f0;
      border-radius: 4px;
      overflow: hidden;
      margin-top: 2px;
    }

    .bar-fill {
      height: 100%;
      background: #22b7ff;
      border-radius: 4px;
      width: 0%;
      transition: width 0.15s ease-out;
    }

    .bar-fill.energy {
      background: #0284c7;
    }

    .controls {
      display: flex;
      flex-direction: column;
      gap: 8px;
      background: #ffffff;
      border-radius: 12px;
      padding: 12px 16px;
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
    }

    .slider-row {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .slider-label {
      font-size: 14px;
      font-weight: 600;
      min-width: 90px;
      color: #475569;
    }

    input[type="range"] {
      flex: 1;
      accent-color: #22b7ff;
      cursor: pointer;
      height: 6px;
    }

    .preset-btns {
      display: flex;
      gap: 8px;
      margin-top: 4px;
    }

    .btn {
      flex: 1;
      padding: 8px 4px;
      font-size: 13px;
      font-weight: 600;
      background: #f1f5f9;
      border: none;
      border-radius: 8px;
      color: #334155;
      cursor: pointer;
      transition: background 0.15s;
    }

    .btn:active, .btn.active {
      background: #22b7ff;
      color: #ffffff;
    }
  </style>
</head>
<body>
  <div class="app-wrap">
    
    <div class="visual-box">
      <svg viewBox="0 0 360 140">
        
        <rect x="15" y="20" width="10" height="90" fill="#cbd5e1" rx="2" />
        <line x1="15" y1="20" x2="15" y2="110" stroke="#94a3b8" stroke-width="2" />
        <line x1="10" y1="35" x2="15" y2="30" stroke="#94a3b8" stroke-width="1.5" />
        <line x1="10" y1="60" x2="15" y2="55" stroke="#94a3b8" stroke-width="1.5" />
        <line x1="10" y1="85" x2="15" y2="80" stroke="#94a3b8" stroke-width="1.5" />
        <line x1="10" y1="105" x2="15" y2="100" stroke="#94a3b8" stroke-width="1.5" />

        
        <line x1="120" y1="15" x2="120" y2="120" class="ref-line" />
        <text x="120" y="132" font-size="10" fill="#94a3b8" text-anchor="middle" font-weight="600">e = 0</text>

        
        <path id="spring" class="spring-path" d="" />

        
        <g id="block" transform="translate(120, 0)">
          <rect x="0" y="38" width="34" height="54" rx="6" fill="#1e2945" />
          <circle cx="17" cy="65" r="5" fill="#ffffff" />
        </g>

        
        <g id="extGroup" opacity="0">
          <line id="extArrow" x1="120" y1="25" x2="120" y2="25" class="extension-line" marker-end="url(#arrow)" />
          <line x1="120" y1="20" x2="120" y2="30" stroke="#f59e0b" stroke-width="1.5" />
          <line id="extEndTick" x1="120" y1="20" x2="120" y2="30" stroke="#f59e0b" stroke-width="1.5" />
        </g>
      </svg>
    </div>

    
    <div class="metric-row">
      <div class="card-tile">
        <div class="tile-label">Extension (e)</div>
        <div class="tile-val" id="extVal">0.0 m</div>
        <div class="bar-bg">
          <div class="bar-fill" id="extBar"></div>
        </div>
      </div>
      <div class="card-tile">
        <div class="tile-label">Energy Store (Ee)</div>
        <div class="tile-val" id="energyVal">0 J</div>
        <div class="bar-bg">
          <div class="bar-fill energy" id="energyBar"></div>
        </div>
      </div>
    </div>

    
    <div class="controls">
      <div class="slider-row">
        <span class="slider-label">Stretch Spring</span>
        <input type="range" id="extSlider" min="0" max="2" step="0.1" value="0">
      </div>
      <div class="preset-btns">
        <button class="btn active" onclick="setPreset(0)">0 m</button>
        <button class="btn" onclick="setPreset(1)">1 m (1×</button>
        <button class="btn" onclick="setPreset(2)">2 m (4× Ee)</button>
      </div>
    </div>
  </div>

  <script>
    const slider = document.getElementById('extSlider');
    const spring = document.getElementById('spring');
    const block = document.getElementById('block');
    const extGroup = document.getElementById('extGroup');
    const extArrow = document.getElementById('extArrow');
    const extEndTick = document.getElementById('extEndTick');
    const extVal = document.getElementById('extVal');
    const extBar = document.getElementById('extBar');
    const energyVal = document.getElementById('energyVal');
    const energyBar = document.getElementById('energyBar');
    const buttons = document.querySelectorAll('.preset-btns .btn');

    const k = 50; // Spring constant N/m
    const x0 = 25; // fixed wall attachment
    const baseEqX = 120; // x position at e = 0
    const scalePx = 95; // 1m extension = 95px

    function generateSpringPath(startX, endX, y, coils) {
      const width = endX - startX;
      const step = width / (coils * 2 + 2);
      let d = `M ${startX} ${y} L ${startX + step} ${y}`;
      
      for (let i = 0; i < coils; i++) {
        const x1 = startX + step * (2 * i + 2);
        const y1 = y - 18;
        const x2 = startX + step * (2 * i + 3);
        const y2 = y + 18;
        d += ` L ${x1} ${y1} L ${x2} ${y2}`;
      }
      
      d += ` L ${endX - step} ${y} L ${endX} ${y}`;
      return d;
    }

    function update(e) {
      const currentBlockX = baseEqX + e * scalePx;
      spring.setAttribute('d', generateSpringPath(x0, currentBlockX, 65, 7));
      block.setAttribute('transform', `translate(${currentBlockX}, 0)`);

      // Extension lines
      if (e > 0.02) {
        extGroup.setAttribute('opacity', '1');
        extArrow.setAttribute('x1', baseEqX);
        extArrow.setAttribute('x2', currentBlockX);
        extEndTick.setAttribute('x1', currentBlockX);
        extEndTick.setAttribute('x2', currentBlockX);
      } else {
        extGroup.setAttribute('opacity', '0');
      }

      // Values
      const energy = 0.5 * k * (e * e);
      const maxEnergy = 0.5 * k * (2 * 2); // 100 J

      extVal.textContent = `${parseFloat(e).toFixed(1)} m`;
      energyVal.textContent = `${Math.round(energy)} J`;

      extBar.style.width = `${(e / 2) * 100}%`;
      energyBar.style.width = `${(energy / maxEnergy) * 100}%`;

      // Preset button highlight
      buttons.forEach(btn => btn.classList.remove('active'));
      if (Math.abs(e - 0) < 0.05) buttons[0].classList.add('active');
      else if (Math.abs(e - 1) < 0.05) buttons[1].classList.add('active');
      else if (Math.abs(e - 2) < 0.05) buttons[2].classList.add('active');
    }

    function setPreset(val) {
      slider.value = val;
      update(val);
    }

    slider.addEventListener('input', (evt) => {
      update(parseFloat(evt.target.value));
    });

    update(0);
  </script>
</body>
</html>

What happens when we zoom in past whole objects down into atoms and chemical bonds?

## The Microscopic Stores: Bonds, Nuclei, and Heat

Meanwhile, the **Nuclear Energy Store** holds energy directly within atomic nuclei, released during nuclear fission or fusion.

The next three stores describe energy held inside microscopic structures and atomic interactions.

The **Chemical Energy Store** is energy stored within the chemical bonds of atoms and molecules; found in fuels, food, metabolic reserves, and chemical batteries.

By contrast, the **nuclear store** is energy held directly within atomic nuclei and released during nuclear fission, fusion, or radioactive decay.

The **Thermal Energy Store** is energy associated with the random motion, kinetic energy, and microscopic arrangement of particles within a substance; higher temperature corresponds to greater thermal store.

<!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: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: #f8f9fa;
    color: #1e2945;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    padding: 12px;
    height: 100%;
    min-height: 380px;
    user-select: none;
    -webkit-user-select: none;
  }

  .nav-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    width: 100%;
    max-width: 480px;
  }

  .store-btn {
    background: #ffffff;
    border: 2px solid #e5e7eb;
    border-radius: 10px;
    padding: 8px 4px;
    font-size: 13px;
    font-weight: 600;
    color: #4b5563;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    transition: all 0.2s ease;
  }

  .store-btn.active {
    border-color: #22b7ff;
    background: #f0f9ff;
    color: #0284c7;
    box-shadow: 0 2px 8px rgba(34, 183, 255, 0.2);
  }

  .stage-box {
    width: 100%;
    max-width: 480px;
    flex: 1;
    margin: 10px 0;
    background: #ffffff;
    border-radius: 12px;
    border: 1px solid #e5e7eb;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
  }

  canvas {
    width: 100%;
    height: 100%;
    display: block;
  }

  .controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 480px;
    padding: 2px 4px;
  }

  .pill {
    font-size: 12px;
    font-weight: 700;
    color: #0284c7;
    background: #e0f2fe;
    padding: 4px 12px;
    border-radius: 20px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
  }

  .slider-wrap {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    font-weight: 600;
    color: #4b5563;
  }

  input[type=range] {
    -webkit-appearance: none;
    width: 110px;
    height: 6px;
    border-radius: 3px;
    background: #e5e7eb;
    outline: none;
  }

  input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #22b7ff;
    cursor: pointer;
    border: 2px solid #ffffff;
    box-shadow: 0 1px 4px rgba(0,0,0,0.2);
  }
</style>
</head>
<body>

  <div class="nav-grid">
    <button class="store-btn active" data-store="0">🔥 Thermal</button>
    <button class="store-btn" data-store="1">💨 Kinetic</button>
    <button class="store-btn" data-store="2">📈 Gravitational</button>
    <button class="store-btn" data-store="3">🏹 Elastic</button>
    <button class="store-btn" data-store="4">🧪 Chemical</button>
    <button class="store-btn" data-store="5">⚛️ Nuclear</button>
  </div>

  <div class="stage-box">
    <canvas id="viewCanvas"></canvas>
  </div>

  <div class="controls">
    <span class="pill" id="paramLabel">Store Level</span>
    <div class="slider-wrap">
      <span id="minText">Low</span>
      <input type="range" id="levelRange" min="1" max="5" value="3" step="1">
      <span id="maxText">High</span>
    </div>
  </div>

<script>
  const canvas = document.getElementById('viewCanvas');
  const ctx = canvas.getContext('2d');
  const buttons = document.querySelectorAll('.store-btn');
  const slider = document.getElementById('levelRange');
  const paramLabel = document.getElementById('paramLabel');

  let currentStore = 0;
  let animId;
  let t = 0;

  const labels = [
    "Temperature",
    "Velocity",
    "Height",
    "Stretch",
    "Bond Energy",
    "Nuclear Binding"
  ];

  function resize() {
    const rect = canvas.getBoundingClientRect();
    canvas.width = rect.width * window.devicePixelRatio;
    canvas.height = rect.height * window.devicePixelRatio;
    ctx.scale(window.devicePixelRatio, window.devicePixelRatio);
  }
  window.addEventListener('resize', resize);
  resize();

  // Thermal particles
  const particles = Array.from({ length: 25 }, () => ({
    x: 0.25 + Math.random() * 0.5,
    y: 0.25 + Math.random() * 0.5,
    vx: (Math.random() - 0.5) * 0.003,
    vy: (Math.random() - 0.5) * 0.003
  }));

  function drawThermal(w, h, lvl) {
    ctx.fillStyle = '#fff7ed';
    ctx.fillRect(w * 0.15, h * 0.15, w * 0.7, h * 0.7);
    ctx.strokeStyle = '#fdba74';
    ctx.lineWidth = 2;
    ctx.strokeRect(w * 0.15, h * 0.15, w * 0.7, h * 0.7);

    const speedMult = lvl * 1.5;
    particles.forEach(p => {
      p.x += p.vx * speedMult;
      p.y += p.vy * speedMult;
      if (p.x < 0.18 || p.x > 0.82) p.vx *= -1;
      if (p.y < 0.20 || p.y > 0.80) p.vy *= -1;

      const px = p.x * w;
      const py = p.y * h;

      // Particle
      ctx.beginPath();
      ctx.arc(px, py, 6 + lvl, 0, Math.PI * 2);
      ctx.fillStyle = lvl > 3 ? '#ef4444' : (lvl > 1 ? '#f97316' : '#38bdf8');
      ctx.fill();

      // Motion streak
      ctx.beginPath();
      ctx.moveTo(px, py);
      ctx.lineTo(px - p.vx * 3000 * (lvl/3), py - p.vy * 3000 * (lvl/3));
      ctx.strokeStyle = 'rgba(239, 68, 68, 0.4)';
      ctx.lineWidth = 2;
      ctx.stroke();
    });
  }

  function drawKinetic(w, h, lvl) {
    const groundY = h * 0.7;
    // Ground
    ctx.strokeStyle = '#cbd5e1';
    ctx.lineWidth = 3;
    ctx.beginPath();
    ctx.moveTo(w * 0.05, groundY);
    ctx.lineTo(w * 0.95, groundY);
    ctx.stroke();

    const speed = lvl * 0.008;
    const carX = ((t * speed) % 0.8 + 0.1) * w;
    const carY = groundY - 24;

    // Motion lines
    ctx.strokeStyle = 'rgba(34, 183, 255, 0.4)';
    ctx.lineWidth = 3;
    for (let i = 1; i <= lvl; i++) {
      ctx.beginPath();
      ctx.moveTo(carX - i * 16, carY + 10);
      ctx.lineTo(carX - i * 16 - 20, carY + 10);
      ctx.stroke();
    }

    // Moving Mass
    ctx.fillStyle = '#0284c7';
    ctx.beginPath();
    ctx.roundRect(carX, carY, 48, 24, 6);
    ctx.fill();

    // Wheels
    ctx.fillStyle = '#1e293b';
    ctx.beginPath();
    ctx.arc(carX + 12, groundY, 6, 0, Math.PI * 2);
    ctx.arc(carX + 36, groundY, 6, 0, Math.PI * 2);
    ctx.fill();
  }

  function drawGravitational(w, h, lvl) {
    const groundY = h * 0.8;
    // Ground
    ctx.strokeStyle = '#94a3b8';
    ctx.lineWidth = 3;
    ctx.beginPath();
    ctx.moveTo(w * 0.1, groundY);
    ctx.lineTo(w * 0.9, groundY);
    ctx.stroke();

    const maxH = h * 0.55;
    const curH = (lvl / 5) * maxH;
    const boxY = groundY - curH - 30;
    const boxX = w * 0.5 - 20;

    // Height indicator line
    ctx.strokeStyle = '#22b7ff';
    ctx.setLineDash([4, 4]);
    ctx.lineWidth = 2;
    ctx.beginPath();
    ctx.moveTo(w * 0.35, groundY);
    ctx.lineTo(w * 0.35, boxY + 15);
    ctx.stroke();
    ctx.setLineDash([]);

    // Arrows on height line
    ctx.fillStyle = '#0284c7';
    ctx.beginPath();
    ctx.moveTo(w * 0.35, boxY + 10);
    ctx.lineTo(w * 0.35 - 5, boxY + 20);
    ctx.lineTo(w * 0.35 + 5, boxY + 20);
    ctx.fill();

    // Mass
    ctx.fillStyle = '#0369a1';
    ctx.beginPath();
    ctx.roundRect(boxX, boxY, 40, 30, 6);
    ctx.fill();

    // Weight label
    ctx.fillStyle = '#ffffff';
    ctx.font = 'bold 12px sans-serif';
    ctx.textAlign = 'center';
    ctx.fillText('m', boxX + 20, boxY + 19);
  }

  function drawElastic(w, h, lvl) {
    const wallX = w * 0.15;
    const groundY = h * 0.65;

    // Wall
    ctx.fillStyle = '#64748b';
    ctx.fillRect(wallX - 10, h * 0.25, 10, h * 0.45);

    const baseLen = w * 0.25;
    const stretch = (lvl / 5) * (w * 0.35);
    const endX = wallX + baseLen + stretch;
    const coils = 10;
    const step = (endX - wallX) / coils;

    // Spring coils
    ctx.strokeStyle = '#0284c7';
    ctx.lineWidth = 3;
    ctx.beginPath();
    ctx.moveTo(wallX, groundY - 20);
    for (let i = 0; i < coils; i++) {
      const cx = wallX + i * step + step / 2;
      const cy = (i % 2 === 0) ? groundY - 35 : groundY - 5;
      ctx.lineTo(cx, cy);
    }
    ctx.lineTo(endX, groundY - 20);
    ctx.stroke();

    // Attached block
    ctx.fillStyle = '#0ea5e9';
    ctx.beginPath();
    ctx.roundRect(endX, groundY - 35, 30, 30, 4);
    ctx.fill();

    // Arrow showing tension
    ctx.strokeStyle = '#ef4444';
    ctx.lineWidth = 2;
    ctx.beginPath();
    ctx.moveTo(endX + 15, groundY - 45);
    ctx.lineTo(endX + 15 - lvl * 6, groundY - 45);
    ctx.stroke();
  }

  function drawChemical(w, h, lvl) {
    const cx = w * 0.5;
    const cy = h * 0.5;
    const bondDist = 35 + lvl * 6;

    // Chemical bonds (spring/line)
    ctx.strokeStyle = '#10b981';
    ctx.lineWidth = 4 + lvl;
    
    const atoms = [
      { x: cx - bondDist, y: cy, r: 18, col: '#059669', label: 'C' },
      { x: cx + bondDist, y: cy, r: 18, col: '#059669', label: 'C' },
      { x: cx, y: cy - bondDist, r: 14, col: '#3b82f6', label: 'H' },
      { x: cx, y: cy + bondDist, r: 14, col: '#3b82f6', label: 'H' }
    ];

    atoms.forEach(a => {
      ctx.beginPath();
      ctx.moveTo(cx, cy);
      ctx.lineTo(a.x, a.y);
      ctx.stroke();
    });

    // Central bond halo
    ctx.beginPath();
    ctx.arc(cx, cy, 8 + lvl * 3, 0, Math.PI * 2);
    ctx.fillStyle = 'rgba(16, 185, 129, 0.2)';
    ctx.fill();

    // Atoms
    atoms.forEach(a => {
      ctx.beginPath();
      ctx.arc(a.x, a.y, a.r, 0, Math.PI * 2);
      ctx.fillStyle = a.col;
      ctx.fill();

      ctx.fillStyle = '#ffffff';
      ctx.font = 'bold 12px sans-serif';
      ctx.textAlign = 'center';
      ctx.textBaseline = 'middle';
      ctx.fillText(a.label, a.x, a.y);
    });
  }

  function drawNuclear(w, h, lvl) {
    const cx = w * 0.5;
    const cy = h * 0.5;
    const count = 4 + lvl * 3;

    // Binding field
    ctx.beginPath();
    ctx.arc(cx, cy, 25 + lvl * 6 + Math.sin(t * 0.05) * 3, 0, Math.PI * 2);
    ctx.fillStyle = 'rgba(168, 85, 247, 0.15)';
    ctx.fill();
    ctx.strokeStyle = '#a855f7';
    ctx.lineWidth = 1.5;
    ctx.stroke();

    // Nucleons (protons + neutrons)
    for (let i = 0; i < count; i++) {
      const angle = (i / count) * Math.PI * 2 + t * 0.01;
      const dist = (i % 2 === 0 ? 12 : 22) * (lvl > 3 ? 1.1 : 0.9);
      const nx = cx + Math.cos(angle) * dist;
      const ny = cy + Math.sin(angle) * dist;

      ctx.beginPath();
      ctx.arc(nx, ny, 10, 0, Math.PI * 2);
      ctx.fillStyle = i % 2 === 0 ? '#ef4444' : '#64748b'; // Proton (red), Neutron (grey)
      ctx.fill();

      ctx.fillStyle = '#ffffff';
      ctx.font = 'bold 10px sans-serif';
      ctx.textAlign = 'center';
      ctx.textBaseline = 'middle';
      ctx.fillText(i % 2 === 0 ? '+' : 'n', nx, ny);
    }
  }

  function render() {
    t++;
    const rect = canvas.getBoundingClientRect();
    const w = rect.width;
    const h = rect.height;

    ctx.clearRect(0, 0, w, h);

    const lvl = parseInt(slider.value, 10);

    switch (currentStore) {
      case 0: drawThermal(w, h, lvl); break;
      case 1: drawKinetic(w, h, lvl); break;
      case 2: drawGravitational(w, h, lvl); break;
      case 3: drawElastic(w, h, lvl); break;
      case 4: drawChemical(w, h, lvl); break;
      case 5: drawNuclear(w, h, lvl); break;
    }

    animId = requestAnimationFrame(render);
  }

  buttons.forEach(btn => {
    btn.addEventListener('click', () => {
      buttons.forEach(b => b.classList.remove('active'));
      btn.classList.add('active');
      currentStore = parseInt(btn.dataset.store, 10);
      paramLabel.textContent = labels[currentStore];
    });
  });

  paramLabel.textContent = labels[0];
  render();
</script>
</body>
</html>

That accounts for six stores—what about the invisible force fields that push and pull from a distance?

The **Magnetic Energy Store** is energy stored in interacting magnetic poles or configurations of magnetic dipoles attracting or repelling across space.

The final two stores hold energy when interacting charges or magnetic poles are pushed together or pulled apart.

The **Electrostatic Energy Store** is energy stored when two or more separated electric charges exert attractive or repulsive forces on one another.

<!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;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      background: #f8f9fa;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

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

    .nav-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 6px;
    }

    .store-btn {
      background: #ffffff;
      border: 1px solid #e6e6e6;
      border-radius: 8px;
      padding: 8px 4px;
      font-size: 13px;
      font-weight: 600;
      color: #6b7280;
      cursor: pointer;
      text-align: center;
      transition: all 0.2s ease;
      box-shadow: 0 1px 2px rgba(0,0,0,0.03);
    }

    .store-btn.active {
      background: #22b7ff;
      color: #ffffff;
      border-color: #22b7ff;
      box-shadow: 0 3px 8px rgba(34, 183, 255, 0.35);
    }

    .stage-container {
      background: #ffffff;
      border: 1px solid #e6e6e6;
      border-radius: 12px;
      height: 220px;
      position: relative;
      overflow: hidden;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    }

    .scene-view {
      position: absolute;
      inset: 0;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease;
    }

    .scene-view.active {
      opacity: 1;
      pointer-events: auto;
    }

    .cue-label {
      position: absolute;
      bottom: 12px;
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      background: #f1f5f9;
      padding: 4px 12px;
      border-radius: 20px;
      border: 1px solid #e2e8f0;
    }

    /* Kinetic Scene */
    .speed-lines {
      display: flex;
      align-items: center;
      gap: 12px;
      animation: carDrift 1.8s ease-in-out infinite alternate;
    }
    .car-icon { font-size: 48px; }
    .motion-trail {
      display: flex;
      flex-direction: column;
      gap: 4px;
    }
    .trail-bar {
      height: 4px;
      background: #22b7ff;
      border-radius: 2px;
    }

    @keyframes carDrift {
      from { transform: translateX(-30px); }
      to { transform: translateX(30px); }
    }

    /* Gravitational Scene */
    .gpe-scene {
      display: flex;
      flex-direction: column;
      align-items: center;
      height: 140px;
      justify-content: space-between;
    }
    .ball-height {
      font-size: 36px;
      animation: bobHeight 2s ease-in-out infinite alternate;
    }
    .height-arrow {
      height: 60px;
      width: 2px;
      border-left: 2px dashed #22b7ff;
      position: relative;
    }
    .ground-line {
      width: 140px;
      height: 4px;
      background: #64748b;
      border-radius: 2px;
    }

    @keyframes bobHeight {
      from { transform: translateY(0px); }
      to { transform: translateY(-40px); }
    }

    /* Chemical Scene */
    .chem-scene {
      display: flex;
      gap: 16px;
      align-items: center;
      font-size: 44px;
    }
    .spark {
      font-size: 28px;
      animation: pulseGlow 1.2s ease-in-out infinite alternate;
    }

    @keyframes pulseGlow {
      from { transform: scale(0.85); opacity: 0.5; }
      to { transform: scale(1.15); opacity: 1; }
    }

    /* Elastic Scene */
    .spring-scene {
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .spring-coils {
      font-size: 32px;
      letter-spacing: -3px;
      color: #3b82f6;
      animation: stretchSpring 1.5s ease-in-out infinite alternate;
    }

    @keyframes stretchSpring {
      from { transform: scaleX(0.7); letter-spacing: -6px; }
      to { transform: scaleX(1.3); letter-spacing: 1px; }
    }

    /* Thermal Scene */
    .thermal-scene {
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
    }
    .cup-icon { font-size: 50px; }
    .heat-waves {
      display: flex;
      gap: 8px;
      font-size: 20px;
      color: #ef4444;
      animation: waveRise 1.4s ease-in-out infinite;
    }

    @keyframes waveRise {
      0% { transform: translateY(6px); opacity: 0.2; }
      50% { opacity: 1; }
      100% { transform: translateY(-12px); opacity: 0; }
    }

    /* Magnetic Scene */
    .mag-scene {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .magnet {
      display: flex;
      border: 2px solid #1e2945;
      border-radius: 4px;
      overflow: hidden;
      font-weight: 800;
      font-size: 16px;
    }
    .pole-n { background: #ef4444; color: #fff; padding: 10px 14px; }
    .pole-s { background: #3b82f6; color: #fff; padding: 10px 14px; }
    .mag-force {
      font-size: 20px;
      color: #64748b;
      animation: fieldPulse 1.2s ease-in-out infinite alternate;
    }

    @keyframes fieldPulse {
      from { transform: scale(0.8); }
      to { transform: scale(1.2); }
    }

    /* Electrostatic Scene */
    .elec-scene {
      display: flex;
      align-items: center;
      gap: 30px;
    }
    .charge {
      width: 46px;
      height: 46px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 26px;
      font-weight: bold;
      color: #ffffff;
    }
    .pos-charge { background: #ef4444; box-shadow: 0 0 12px rgba(239, 68, 68, 0.4); }
    .neg-charge { background: #3b82f6; box-shadow: 0 0 12px rgba(59, 130, 246, 0.4); }

    /* Nuclear Scene */
    .nuc-scene {
      position: relative;
      width: 100px;
      height: 100px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .nucleus {
      font-size: 42px;
      z-index: 2;
      animation: coreVibe 0.2s linear infinite alternate;
    }
    .orbit-ring {
      position: absolute;
      width: 90px;
      height: 90px;
      border: 2px dashed #94a3b8;
      border-radius: 50%;
      animation: spinOrbit 4s linear infinite;
    }

    @keyframes spinOrbit {
      to { transform: rotate(360deg); }
    }
    @keyframes coreVibe {
      from { transform: scale(0.96); }
      to { transform: scale(1.04); }
    }

    /* Stepper Controls */
    .controls {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 8px;
    }
    .ctrl-btn {
      background: #ffffff;
      border: 1px solid #e6e6e6;
      border-radius: 6px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 600;
      color: #1e2945;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .ctrl-btn:active { background: #f1f5f9; }

    .dots-row {
      display: flex;
      gap: 6px;
    }
    .step-dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      transition: background 0.2s;
    }
    .step-dot.active {
      background: #22b7ff;
      transform: scale(1.2);
    }
  </style>
</head>
<body>
  <div class="main-layout">
    <div class="nav-grid" id="navGrid">
      <button class="store-btn active" data-idx="0">Kinetic</button>
      <button class="store-btn" data-idx="1">Gravitational</button>
      <button class="store-btn" data-idx="2">Chemical</button>
      <button class="store-btn" data-idx="3">Elastic</button>
      <button class="store-btn" data-idx="4">Thermal</button>
      <button class="store-btn" data-idx="5">Magnetic</button>
      <button class="store-btn" data-idx="6">Electrostatic</button>
      <button class="store-btn" data-idx="7">Nuclear</button>
    </div>

    <div class="stage-container">
      
      <div class="scene-view active" id="scene-0">
        <div class="speed-lines">
          <div class="motion-trail">
            <div class="trail-bar" style="width: 24px;"></div>
            <div class="trail-bar" style="width: 38px;"></div>
            <div class="trail-bar" style="width: 18px;"></div>
          </div>
          <div class="car-icon">🚗</div>
        </div>
        <div class="cue-label">Speed & Motion</div>
      </div>

      
      <div class="scene-view" id="scene-1">
        <div class="gpe-scene">
          <div class="ball-height">⚽</div>
          <div class="height-arrow"></div>
          <div class="ground-line"></div>
        </div>
        <div class="cue-label">Height Above Ground</div>
      </div>

      
      <div class="scene-view" id="scene-2">
        <div class="chem-scene">
          <span>🔋</span>
          <span class="spark">⚡</span>
          <span>🍎</span>
        </div>
        <div class="cue-label">Bonds in Fuel & Food</div>
      </div>

      
      <div class="scene-view" id="scene-3">
        <div class="spring-scene">
          <span>🧱</span>
          <div class="spring-coils">⟿⟿⟿⟿</div>
          <span>📦</span>
        </div>
        <div class="cue-label">Stretched or Squashed</div>
      </div>

      
      <div class="scene-view" id="scene-4">
        <div class="thermal-scene">
          <div class="heat-waves">
            <span>~</span><span>~</span><span>~</span>
          </div>
          <div class="cup-icon">☕</div>
        </div>
        <div class="cue-label">Temperature & Heat</div>
      </div>

      
      <div class="scene-view" id="scene-5">
        <div class="mag-scene">
          <div class="magnet">
            <div class="pole-n">N</div>
            <div class="pole-s">S</div>
          </div>
          <div class="mag-force">⇄</div>
          <div class="magnet">
            <div class="pole-n">N</div>
            <div class="pole-s">S</div>
          </div>
        </div>
        <div class="cue-label">Separated Magnetic Poles</div>
      </div>

      
      <div class="scene-view" id="scene-6">
        <div class="elec-scene">
          <div class="charge pos-charge">+</div>
          <div class="mag-force">⇄</div>
          <div class="charge neg-charge">−</div>
        </div>
        <div class="cue-label">Separated Electric Charges</div>
      </div>

      
      <div class="scene-view" id="scene-7">
        <div class="nuc-scene">
          <div class="orbit-ring"></div>
          <div class="nucleus">⚛️</div>
        </div>
        <div class="cue-label">Atomic Nucleus</div>
      </div>
    </div>

    <div class="controls">
      <button class="ctrl-btn" id="prevBtn">◀ Prev</button>
      <div class="dots-row" id="dotsRow">
        <div class="step-dot active" data-idx="0"></div>
        <div class="step-dot" data-idx="1"></div>
        <div class="step-dot" data-idx="2"></div>
        <div class="step-dot" data-idx="3"></div>
        <div class="step-dot" data-idx="4"></div>
        <div class="step-dot" data-idx="5"></div>
        <div class="step-dot" data-idx="6"></div>
        <div class="step-dot" data-idx="7"></div>
      </div>
      <button class="ctrl-btn" id="nextBtn">Next ▶</button>
    </div>
  </div>

  <script>
    let currentIdx = 0;
    const total = 8;
    let autoTimer = null;

    const navButtons = document.querySelectorAll('.store-btn');
    const scenes = document.querySelectorAll('.scene-view');
    const dots = document.querySelectorAll('.step-dot');

    function showStore(idx) {
      currentIdx = (idx + total) % total;
      
      navButtons.forEach((btn, i) => {
        btn.classList.toggle('active', i === currentIdx);
      });
      scenes.forEach((scene, i) => {
        scene.classList.toggle('active', i === currentIdx);
      });
      dots.forEach((dot, i) => {
        dot.classList.toggle('active', i === currentIdx);
      });
    }

    function resetTimer() {
      clearInterval(autoTimer);
      autoTimer = setInterval(() => {
        showStore(currentIdx + 1);
      }, 3500);
    }

    navButtons.forEach(btn => {
      btn.addEventListener('click', () => {
        showStore(parseInt(btn.getAttribute('data-idx')));
        resetTimer();
      });
    });

    dots.forEach(dot => {
      dot.addEventListener('click', () => {
        showStore(parseInt(dot.getAttribute('data-idx')));
        resetTimer();
      });
    });

    document.getElementById('prevBtn').addEventListener('click', () => {
      showStore(currentIdx - 1);
      resetTimer();
    });

    document.getElementById('nextBtn').addEventListener('click', () => {
      showStore(currentIdx + 1);
      resetTimer();
    });

    resetTimer();
  </script>
</body>
</html>

How do you identify these eight stores in a complex real-world exam scenario?

## Worked Example: A Battery-Powered Drone

Consider a battery-powered drone that lifts off from the grass, accelerates upward, and warms up slightly as its motors spin.

To solve this, list the stores that change: the battery loses **chemical energy**, while the drone gains **gravitational potential energy** (rising higher), **kinetic energy** (moving faster), and **thermal energy** (in the warmed-up motors).

<!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>Drone Energy Stores</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      user-select: none;
    }

    body {
      background: #f8f9fa;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 16px;
      gap: 12px;
    }

    /* Controls */
    .controls {
      display: flex;
      gap: 8px;
      width: 100%;
      max-width: 480px;
    }

    .btn-step {
      flex: 1;
      padding: 8px 4px;
      font-size: 14px;
      font-weight: 600;
      border: 2px solid transparent;
      border-radius: 8px;
      background: #ffffff;
      color: #6b7280;
      cursor: pointer;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
      transition: all 0.25s ease;
      text-align: center;
    }

    .btn-step.active {
      background: #22b7ff;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(34, 183, 255, 0.4);
    }

    /* Main Display */
    .stage-container {
      display: flex;
      width: 100%;
      max-width: 480px;
      gap: 16px;
      height: 260px;
    }

    /* Drone Sky Canvas */
    .sky-box {
      flex: 1.1;
      background: linear-gradient(180deg, #dbeafe 0%, #eff6ff 70%, #e2e8f0 100%);
      border-radius: 12px;
      position: relative;
      overflow: hidden;
      display: flex;
      justify-content: center;
      box-shadow: inset 0 0 8px rgba(0,0,0,0.04);
    }

    .ground-line {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 14px;
      background: #94a3b8;
    }

    .drone-wrap {
      position: absolute;
      bottom: 16px;
      left: 50%;
      transform: translateX(-50%);
      transition: bottom 0.6s cubic-bezier(0.34, 1.2, 0.64, 1);
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .drone-body {
      font-size: 40px;
      line-height: 1;
      filter: drop-shadow(0 4px 6px rgba(0,0,0,0.15));
      position: relative;
    }

    .heat-glow {
      position: absolute;
      inset: -6px;
      border-radius: 50%;
      background: radial-gradient(circle, rgba(239, 68, 68, 0.5) 0%, rgba(239, 68, 68, 0) 70%);
      opacity: 0;
      transition: opacity 0.5s ease;
      pointer-events: none;
    }

    .motion-lines {
      opacity: 0;
      display: flex;
      gap: 6px;
      margin-top: -2px;
      transition: opacity 0.4s ease;
    }

    .motion-lines span {
      width: 3px;
      height: 12px;
      background: #3b82f6;
      border-radius: 2px;
      opacity: 0.6;
    }

    /* Energy Stores Column */
    .stores-column {
      flex: 1.3;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      gap: 8px;
    }

    .store-card {
      background: #ffffff;
      border-radius: 10px;
      padding: 8px 10px;
      display: flex;
      flex-direction: column;
      gap: 5px;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    }

    .store-label {
      font-size: 13px;
      font-weight: 600;
      color: #1e2945;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .store-bar-track {
      width: 100%;
      height: 8px;
      background: #f1f5f9;
      border-radius: 4px;
      overflow: hidden;
    }

    .store-bar-fill {
      height: 100%;
      border-radius: 4px;
      transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    }

    /* Store specific fill colors */
    .fill-chemical { background: #10b981; }
    .fill-gravitational { background: #22b7ff; }
    .fill-kinetic { background: #f59e0b; }
    .fill-thermal { background: #ef4444; }

    /* Bottom Status */
    .status-badge {
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      display: flex;
      align-items: center;
      gap: 6px;
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="btn-step active" onclick="setStep(0)">Ground</button>
    <button class="btn-step" onclick="setStep(1)">Climbing</button>
    <button class="btn-step" onclick="setStep(2)">High Flight</button>
  </div>

  
  <div class="stage-container">
    
    <div class="sky-box">
      <div class="drone-wrap" id="drone">
        <div class="heat-glow" id="droneHeat"></div>
        <div class="drone-body">🚁</div>
        <div class="motion-lines" id="droneMotion">
          <span></span><span></span><span></span>
        </div>
      </div>
      <div class="ground-line"></div>
    </div>

    
    <div class="stores-column">
      <div class="store-card">
        <div class="store-label">
          <span>🔋 Chemical</span>
          <span id="txt-chem">100%</span>
        </div>
        <div class="store-bar-track">
          <div class="store-bar-fill fill-chemical" id="bar-chem" style="width: 100%;"></div>
        </div>
      </div>

      <div class="store-card">
        <div class="store-label">
          <span>⬆️ Gravitational</span>
          <span id="txt-grav">0%</span>
        </div>
        <div class="store-bar-track">
          <div class="store-bar-fill fill-gravitational" id="bar-grav" style="width: 0%;"></div>
        </div>
      </div>

      <div class="store-card">
        <div class="store-label">
          <span>💨 Kinetic</span>
          <span id="txt-kin">0%</span>
        </div>
        <div class="store-bar-track">
          <div class="store-bar-fill fill-kinetic" id="bar-kin" style="width: 0%;"></div>
        </div>
      </div>

      <div class="store-card">
        <div class="store-label">
          <span>🔥 Thermal</span>
          <span id="txt-therm">0%</span>
        </div>
        <div class="store-bar-track">
          <div class="store-bar-fill fill-thermal" id="bar-therm" style="width: 0%;"></div>
        </div>
      </div>
    </div>
  </div>

  <div class="status-badge" id="summary">
    <span>✦</span><span>Stores Transform</span>
  </div>

  <script>
    const stepsData = [
      { bottom: 16, chem: 100, grav: 0, kin: 0, therm: 0, heat: 0, lines: 0 },
      { bottom: 110, chem: 60, grav: 45, kin: 85, therm: 25, heat: 0.4, lines: 1 },
      { bottom: 195, chem: 20, grav: 90, kin: 95, therm: 60, heat: 0.9, lines: 1 }
    ];

    function setStep(idx) {
      // Update buttons
      const btns = document.querySelectorAll('.btn-step');
      btns.forEach((b, i) => b.classList.toggle('active', i === idx));

      const d = stepsData[idx];

      // Update Drone position & effects
      document.getElementById('drone').style.bottom = d.bottom + 'px';
      document.getElementById('droneHeat').style.opacity = d.heat;
      document.getElementById('droneMotion').style.opacity = d.lines;

      // Update Bars & Labels
      document.getElementById('bar-chem').style.width = d.chem + '%';
      document.getElementById('txt-chem').textContent = d.chem + '%';

      document.getElementById('bar-grav').style.width = d.grav + '%';
      document.getElementById('txt-grav').textContent = d.grav + '%';

      document.getElementById('bar-kin').style.width = d.kin + '%';
      document.getElementById('txt-kin').textContent = d.kin + '%';

      document.getElementById('bar-therm').style.width = d.therm + '%';
      document.getElementById('txt-therm').textContent = d.therm + '%';
    }

    // Auto cycle through steps calmly
    let current = 0;
    setInterval(() => {
      current = (current + 1) % 3;
      setStep(current);
    }, 3200);
  </script>
</body>
</html>

A common mistake on exams is writing 'electricity', 'light', or 'sound' as an energy store.

Light, sound, and electrical currents are **energy pathways** (ways of transferring energy between systems), not static stores where energy sits over time.

In the 1840s, English physicist **James Prescott Joule** proved through paddle-wheel experiments that mechanical work transforms directly into thermal energy, formalizing our modern rule that energy can be stored in different forms but never created or destroyed.

Whenever you look at any physical system, ask yourself two questions: *What is moving or positioned?* and *What is interacting at the atomic or field level?*

science

Identifying Energy Stores in GCSE Physics. Identify the eight primary energy stores (kinetic, gravitational potential, elastic potential, chemical, thermal, electrostatic, magnetic, and nuclear) in physical systems.

GCSE Physics: Energy Stores and Transfers

Key Stage 4 Physics: Energy Stores and Changes in Systems

AQA GCSE Physics Revision Notes: Energy Stores & Pathways

When teaching energy stores at GCSE, strictly enforce the post-2015 Institute of Physics (IOP) energy model terminology. Emphasize using the noun 'store' (e.g., 'energy in the kinetic store' rather than 'kinetic energy as a substance'). Explicitly contrast 'stores' (where energy resides in a static or steady state) with 'pathways/transfers' (the mechanisms through which energy shifts, such as forces, electric currents, heating, and radiation) to prevent widespread confusion. Utilize the 'C-K-G-E-T-M-E-N' mnemonic (Chemical, Kinetic, Gravitational, Elastic, Thermal, Magnetic, Electrostatic, Nuclear) for student retrieval practice.