Examples of conduction convection radiation worksheet | Live ... - Free Printable

Let's go through each example on the worksheet and identify whether the heat transfer is conduction, convection, or radiation. I'll explain each one clearly.

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🔹 Definitions:

- Conduction: Heat transfer through direct contact between materials (especially solids).
- Convection: Heat transfer through fluids (liquids or gases) via circulation currents.
- Radiation: Heat transfer through electromagnetic waves (no medium needed, e.g., sunlight).

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✔ Answers with Explanations:

1) Warming hand over a radiator.
→ Radiation
*Explanation:* The radiator emits infrared radiation (heat waves), which warm your hand without touching it. Even though the radiator is hot, the warming happens through radiation in the air. (Note: Some conduction might occur if you touch it, but here it’s "over" the radiator, so radiation is best.)

2) Eggs cooking in a frying pan.
→ Conduction
*Explanation:* The heat from the stove transfers to the pan, then directly to the eggs through direct contact. This is conduction.

3) Snowman melting in the sun.
→ Radiation
*Explanation:* The Sun heats the snowman via electromagnetic waves (sunlight). No contact or fluid motion—just radiation.

4) Water boiling in a kettle.
→ Convection
*Explanation:* The bottom of the kettle heats up, water at the bottom gets hotter, rises, cooler water sinks, creating convection currents. Also involves conduction from the kettle to water, but the *boiling* process relies on convection.

5) Warmth from the fireplace circulating through the house.
→ Convection
*Explanation:* The hot air rises from the fireplace, circulates around the room, and warms the space. This is convection current in air.

6) Tongue freezing to a metal pole.
→ Conduction
*Explanation:* When the tongue touches the cold metal, heat is rapidly conducted away from the tongue into the metal, causing freezing. Direct contact = conduction.

7) Newt boiling in a hot caldron.
→ Conduction & Convection
*Explanation:* The fire heats the pot (conduction), then the liquid inside heats up and circulates (convection). But since the question asks for the best fit, and the newt is submerged in liquid that’s boiling due to heat transfer through the liquid, convection is the dominant process. However, the heat initially comes from conduction to the pot.
✔ Best answer: Convection (since the boiling and heating of the liquid is primarily by convection currents).

8) Ice melting on a hotplate.
→ Conduction
*Explanation:* The ice is in direct contact with the hot surface, so heat flows from the hotplate to the ice via conduction.

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📝 Final Answers:

1) Radiation
2) Conduction
3) Radiation
4) Convection
5) Convection
6) Conduction
7) Convection
8) Conduction

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✔ Summary Table:

| # | Situation | Heat Transfer |
|---|---------|---------------|
| 1 | Warming hand over radiator | Radiation |
| 2 | Eggs cooking in pan | Conduction |
| 3 | Snowman melting in sun | Radiation |
| 4 | Water boiling in kettle | Convection |
| 5 | Fireplace warmth circulating | Convection |
| 6 | Tongue freezing to pole | Conduction |
| 7 | Newt boiling in caldron | Convection |
| 8 | Ice melting on hotplate | Conduction |

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