How Batteries Store Energy

What this Spark covers

• A tiny energy lunchbox
  Big idea A battery is an energy lunchbox 🔋 Your torch, your toy car, your parent's phone — none of them are plugged into the wall. So where does the energy come from? From a battery. A battery is like a lunchbox, but instead of packing rice and chicken, it packs energy — ready to be used later. battery = lunchbox In this lesson you will find out how the energy gets packed in, where it hides, and how it comes back out to make things move, glow and beep. Tap Next to open the lunchbox. 👉
• Chemical energy: the hidden kind
  Step 1 The energy hides as chemicals Here is the surprise: a battery does not store electricity inside it, the way a bottle stores water. A battery stores chemical energy — energy locked up inside special powders and pastes. When you switch on your torch, the chemicals start changing, and that change makes electricity. Tap each energy card and sort it: is it energy that is stored (waiting), or energy that is doing something right now? Shuffle again ↺ Sorted: 0 / 6 Food, petrol and batteries are all in the same family: they hold stored chemical energy, quietly, until we need it. That is why a b
• Inside a battery
  Step 2 What's inside? Tap and find out 👆 Cut a battery open (never do this at home — the paste inside can hurt you!) and you would find three main parts. + tap tap – tap Tap a coloured part of the battery to learn its job. Parts found: 0 / 3 The two ends are called terminals: the + end and the – end. The goo in the middle is the electrolyte — a big word that just means "the wet chemical bit that lets tiny charged pieces travel across".
• Electrons take a walk
  Step 3 Energy comes out when electrons take a walk 🚶‍♂️⚡ Inside the battery live billions of electrons — pieces far too small to see. At the – end they are packed tight and eager to move. But there is a rule: electrons can only travel along a complete loop. That loop is called a circuit. No loop, no journey, no energy out. Tap the gap in the wire to close the circuit and watch the electrons walk. – + 💡 switch When the loop is closed, electrons stream out of the – end, through the bulb (where they give up energy as light and heat), and back into the + end. Meanwhile the chemicals inside the bat
• Why batteries go flat
  Step 4 Why does a battery go flat? 🪫 The chemicals inside are like a stack of biscuits. Every second the torch shines, a few more get used up. When the useful chemicals have all changed, the pushing stops — the battery is flat. The energy did not vanish. It left the battery as light, sound, movement and heat. Hold the button to run the torch. Watch the chemicals turn and the energy bar drop. 🔦 Hold to shine Fresh battery ↺ Energy left: 100% 🔵 fresh chemicals → 🔴 used-up chemicals A rechargeable battery is special: plugging it in pushes the chemicals backwards, turning the used ones back into f
• Build the energy story
  Step 5 Build the energy story 🧩 Energy never disappears — it just changes form. Scientists call this an energy change. For a torch, the story goes in a straight line. Tap a card, then tap a slot to build the energy story of a torch. Start over ↺ Hint: think about what the battery holds, what travels along the wire, and what your eyes finally see.
• Bigger store, longer play
  Step 6 Big battery, small battery 📏 Why does a torch take fat D batteries while a TV remote takes skinny AAA ones? Because a bigger battery holds more chemicals — and more chemicals means more stored energy, so it lasts longer before it goes flat. Tap a battery to see how long it can keep a toy car running. Tap one of the three batteries above. Careful though — a bigger battery does not always mean "more powerful". It mostly means lasts longer, because the store is bigger. 🕒
• Battery safety
  Step 7 Handle with care 🧑‍🔬 The chemicals that store the energy are useful — but they are not toys. Here is what every young scientist in Singapore should know. Never open or cut a battery. The paste inside can burn skin and eyes. Never heat a battery or throw it in a fire. Heat makes the chemicals react too fast, and it can burst. Never put a battery in your mouth. Tiny button batteries are extremely dangerous if swallowed — tell an adult at once. Don't mix old and new batteries in the same toy — it makes them leak. Recycle used batteries at the e-waste bins in many Singapore malls and HDB bl
• You've got it!
  🔋⚡🎉 You now know how batteries store energy! The whole story in five lines A battery is an energy lunchbox — it packs energy for later. The energy is stored as chemical energy, not as electricity sitting in a tank. Inside are two terminals (+ and –) and a chemical electrolyte. Close the circuit and electrons walk round the loop: chemical → electrical → light, sound, movement and heat. When the useful chemicals are used up, the battery is flat. Rechargeables push the chemicals backwards; the rest get recycled. ♻️ Try this at home 🏠 Go on a battery hunt! Count how many things in your home run on

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