Grade 4 (age 9-10)

Heat Transfer

Heat always moves from a hotter spot to a cooler one. Leave a metal spoon in hot soup and its handle heats up, as heat travels through the solid by conduction. Warm water and air rise and loop as convection, and sunlight reaches you by radiation with no matter. Tap the buttons to compare all three.

How does heat move?

🔥 Heat transfer: Conduction

①Conduction: heat passes through the object

②A spoon in hot water heats up at the handle

③Mostly in solids

④Metals conduct heat better than wood

Summary

3 Modes of Heat Transfer

Conduction (solid) / Convection (liquid·gas) / Radiation (works in vacuum)

Heat always moves from hot to cold

🎯 Key Points

①Heat moves hot → cold

②Conduction: through objects (solids)

③Convection: by flow (liquids, gases)

④Radiation: works without matter (space)

⑤Insulators are materials that block heat transfer

Examples and Unit Test

Example 1

A metal spoon left in hot soup became hot all the way to its handle. Which method of heat transfer is this?

Conduction is heat passing along an object from the hotter side to the colder side.

Heat traveled along the metal from the part in the soup to the handle.

▸ Conduction

Conduction mainly moves heat along a solid object.

Example 2

Water at the bottom of a kettle warms and rises; sunlight reaches the Earth. Which transfer method is each?

A flow where warmed liquid or gas rises and the cooler part sinks is convection.

Across the near-empty space between the Sun and Earth, heat still reaches us, so that is radiation.

▸ Boiling water = convection / sunlight = radiation

Convection is the flow of liquids and gases; radiation carries heat even without matter.

Unit-test style

Which statement about heat transfer is correct?

①Heat moves from a cold place to a hot place

②Radiation transfers heat even without matter

③Conduction mainly happens in gases

④Convection happens well in solids

⑤Wood transfers heat better than metal

▸ ② Radiation transfers heat even without matter

Like the heat from the Sun, radiation transfers heat even through empty space where there is no matter.

Heat moves from hot to cold (①), conduction occurs in solids (③), convection occurs in liquids and gases (④), and metal transfers heat better than wood (⑤).

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