Heat and Temperature: Year 3 Study Guide
Heat makes things warmer and always travels from a hotter place to a cooler one.
Heat is a form of energy. It comes from sources such as the Sun, fire, electric heaters, friction (rubbing your hands together) and living things. We feel heat as warmth, and we measure how hot something is with a thermometer in degrees Celsius (°C). Water freezes at 0 °C and boils at 100 °C.
Heat always moves from something hotter to something cooler. A hot cup of tea warms your hands because heat flows from the cup to your skin, not because cold flows the other way.
Conductors and insulators
A conductor lets heat travel through it easily. Metals such as copper and aluminium are good conductors, which is why saucepans are made of metal. An insulator slows heat down. Wood, plastic, wool and air are insulators. That is why saucepan handles are plastic, and why a woolly jumper keeps you warm: it traps air close to your body.
| Material | Conductor or insulator? | Used for |
|---|---|---|
| Copper | Conductor | Cooking pots |
| Plastic | Insulator | Handles, lunch boxes |
| Wool | Insulator | Jumpers, blankets |
| Aluminium foil | Conductor | Baking trays |
Investigate: which keeps water warm?
A fair test changes one thing and keeps the rest the same.
Which material is best at keeping a cup of warm water warm?
I think wool will keep it warmest.
Wrap identical cups in wool, foil and paper. Pour in the same amount of warm water.
Record the temperature every five minutes.
Compare results with your prediction.
Heat in the real world
In Australia, houses are designed to stay cool in summer and warm in winter. Light-coloured roofs reflect the Sun's heat, and insulation in the ceiling slows heat flow. Bushfire safety also depends on understanding heat: clearing dry material around a home reduces what can burn.
Worked examples and common mistakes
Example: Why does an ice cube melt in your hand? Heat flows from your warm hand to the cold ice. Example: Why do we put a metal spoon in hot soup and find the handle gets hot? Metal is a conductor. A common idea is that jumpers 'make' heat; in fact, they trap the heat your body already makes. Never touch hot items; use an adult for anything that needs heat.
Check your understanding: model answers
1. Plastic and wood are insulators, so the handle stays cool enough to hold. 2. Wrap identical cups in different materials, pour in the same amount of warm water, and record the temperature at the same times. Change only the material. 3. Wool traps air close to the body. That slows the heat leaving, but the heat comes from your body.
✨ Key Takeaways
- Heat is energy that makes things warmer; it comes from the Sun, fire, friction and more.
- Heat moves from hot to cold.
- Conductors let heat flow easily; insulators slow it.
- Fair tests change only one thing.
💬 Questions for Discussion & Reflection
- Why are saucepan handles often made of plastic or wood?
- Plan a fair test to find which cup keeps a drink warm the longest.
- Why does a wool blanket keep you warm without making its own heat?
Print a science observation log →