Conduction, convection or radiation worksheet - Free Printable

Let's solve this step-by-step by identifying whether each image represents conduction, convection, or radiation. Here's a quick recap of the three methods of heat transfer:

- Conduction: Heat transfer through direct contact between materials (usually solids).
- Convection: Heat transfer through fluids (liquids or gases) via circulation (e.g., warm air rising).
- Radiation: Heat transfer through electromagnetic waves (e.g., sunlight, fire glow), does not require a medium.

Now let’s go through each image:

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1. Toaster
- The bread is heated by electric heating elements that touch the bread.
→ Conduction

2. Hairdryer
- Heats air and blows it out to dry hair. Warm air moves around.
→ Convection

3. Iron
- Heats up and touches fabric directly to remove wrinkles.
→ Conduction

4. Campfire
- Fire emits heat and light; you feel warmth without touching it.
→ Radiation (also some convection, but primarily radiation)

5. Space heater
- Heats air near it, which rises and circulates room air.
→ Convection

6. Person sunbathing
- Sunlight warms the person through electromagnetic waves.
→ Radiation

7. Grill (barbecue)
- Food is cooked by heat from below, often with flames or hot coals.
→ Conduction (from grill grates) and Radiation (from fire/heat source). But since it's a grill, the primary method is Conduction from the hot metal, though Radiation also plays a role.
→ Mainly Conduction & Radiation — but for simplicity in such exercises, often Radiation if it's an open flame, or Conduction if the food touches the grill.
However, since it's a charcoal grill, and heat comes from below and radiates upward, Radiation is significant. But the food also touches the grate → Both, but typically labeled as Radiation due to infrared heat from fire.

→ Radiation (commonly accepted answer for grills)

8. Oven (with bread baking)
- Oven heats air inside, which circulates and cooks food.
→ Convection (and some radiation from oven walls)

9. Cup of coffee
- Steam rising indicates heat loss through air. The cup transfers heat to your hand when held.
→ Conduction (when holding the cup), but the steam shows convection (hot air rising).
However, the question is about how the coffee loses heat? It's mainly Convection (air above gets warm), and Radiation too.
But if the focus is on the cup warming your hands, it's Conduction.
Since it's just a steaming cup, likely the emphasis is on Convection (steam rising).

→ Convection

10. Frying pan on fire
- Pan is heated by direct contact with flame.
→ Conduction (pan conducts heat from flame)

11. Heat gun
- Blows hot air to shrink wrap or dry things.
→ Convection

12. Air conditioner (or air cooler)
- Shows cold air coming down, hot air going up.
→ Convection (air circulation)

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Final Answers:

1. Toaster → Conduction
2. Hairdryer → Convection
3. Iron → Conduction
4. Campfire → Radiation
5. Space heater → Convection
6. Sunbathing → Radiation
7. Grill → Radiation (or Conduction & Radiation — but usually Radiation)
8. Oven → Convection (and radiation, but Convection is dominant in modern ovens)
9. Cup of coffee → Convection (steam rising)
10. Frying pan → Conduction
11. Heat gun → Convection
12. Air conditioner → Convection

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Summary Table:

| # | Image | Method |
|---|-------------------|----------------|
| 1 | Toaster | Conduction |
| 2 | Hairdryer | Convection |
| 3 | Iron | Conduction |
| 4 | Campfire | Radiation |
| 5 | Space heater | Convection |
| 6 | Sunbathing | Radiation |
| 7 | Grill | Radiation |
| 8 | Oven | Convection |
| 9 | Coffee cup | Convection |
|10 | Frying pan | Conduction |
|11 | Heat gun | Convection |
|12 | Air conditioner | Convection |

✔ Answer Key:
1. Conduction
2. Convection
3. Conduction
4. Radiation
5. Convection
6. Radiation
7. Radiation
8. Convection
9. Convection
10. Conduction
11. Convection
12. Convection

Let me know if you'd like this formatted as a printable worksheet!