Heat transfer online pdf activity - Free Printable

Let's solve this step-by-step.

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Part 1: Fill in the blanks using words from the word box

Word Box:
- faster
- hot
- less
- solid
- fluid
- conduction
- more
- convection
- energy
- emit
- warmer
- matter
- transfer
- absorb
- temperature
- radiation
- contact
- cold
- vibrate
- waves

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Paragraph:

> All matter has heat. Heat is a form of energy caused by particles in an object that vibrate. The more the particles of an object vibrate, the hotter the object will be. Because particles of an object are always moving, heat transfer is always happening. Heat always flows in the same direction: from hot to cold. Heat transfer will stop once two objects reach the same temperature. This is known as equilibrium.

> There are three key ways that heat transfers. With solid objects, heat transfers when the objects come into direct contact with other things. This is known as conduction. Liquids and gases are different. Because these two states of matter flow, or are fluid, heat transfer happens when warmer, less dense particles rise and cooler, more dense particles sink. This ongoing process is known as a convection current. Heat can also be transferred through space (distance) in the form of waves. This process is known as radiation. All objects give off, or emit, some heat. All objects also take in, or absorb, heat.

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✔ Completed Paragraph with Answers:

All matter has heat. Heat is a form of energy caused by particles in an object that vibrate. The more the particles of an object vibrate, the hotter the object will be. Because particles of an object are always moving, heat transfer is always happening. Heat always flows in the same direction: from hot to cold. Heat transfer will stop once two objects reach the same temperature. This is known as equilibrium.

There are three key ways that heat transfers. With solid objects, heat transfers when the objects come into direct contact with other things. This is known as conduction. Liquids and gases are different. Because these two states of matter flow, or are fluid, heat transfer happens when warmer, less dense particles rise and cooler, more dense particles sink. This ongoing process is known as a convection current. Heat can also be transferred through space (distance) in the form of waves. This process is known as radiation. All objects give off, or emit, some heat. All objects also take in, or absorb, heat.

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Part 2: Identify the method of heat transfer in each illustration

Now let’s analyze each image:

#### 1. Microwave oven
- A microwave heats food using electromagnetic waves (microwaves).
- This is radiation.
- ✔ Answer: Radiation

#### 2. Hair dryer drying hair
- The hair dryer blows warm air, which moves and transfers heat via air currents.
- Warm air rises and circulates — this is convection.
- ✔ Answer: Convection

#### 3. Pan on stove with handle
- The pan is heated from the bottom, and heat travels through the metal to the handle.
- This is conduction (direct contact through a solid).
- ✔ Answer: Conduction

#### 4. Person drinking hot coffee
- The person holds a cup of hot coffee; heat transfers from the cup to their hand.
- This is conduction (direct contact between the hand and the cup).
- ✔ Answer: Conduction

#### 5. Campfire
- The fire emits heat that warms the surrounding area without direct contact.
- This is radiation (heat travels through space as infrared waves).
- ✔ Answer: Radiation

#### 6. Refrigerator with arrows showing circulation
- The arrows show air circulating inside the fridge — cool air sinks, warm air rises.
- This is convection (movement of air due to temperature differences).
- ✔ Answer: Convection

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✔ Final Answers for Images:

1. Radiation
2. Convection
3. Conduction
4. Conduction
5. Radiation
6. Convection

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📝 Summary of Key Concepts:

- Conduction: Heat transfer through direct contact (solids).
- Convection: Heat transfer through fluids (liquids/gases) via movement of particles.
- Radiation: Heat transfer through electromagnetic waves (no medium needed).

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