1. Chapter 6- Heat 7th Grade Science
© Fall 2005, Pflugerville ISD, 8th Grade

2. Unit A : Chapter 1 : Section 1
Chapter 6- Heat
Section 1: What is Temperature?
Section 2: What is Heat?
Section 3: Matter & Heat
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3. What is Temperature? What Do You Think?
What happens when you use a thermometer to measure temperature?
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4. Temperature Depends on Kinetic Energy
Kinetic Energy is the energy of motion
The faster the particles of matter move, the more kinetic energy they have
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5. Unit A : Chapter 1 : Section 1
What is Temperature?
Measuring Temperature
Temperature is a measure of the Average Kinetic Energy of a substance
When you measure temperature, you are measuring the average motion of the atoms
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6. Unit A : Chapter 1 : Section 1
What is Temperature?
Temperature is expressed by one of 3 scales:
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7. Unit A : Chapter 1 : Section 1
What is Temperature?
Thermal Expansion- As temperature rises, volume increases
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8. Unit A : Chapter 1 : Section 1
What is Temperature?
Thermal Expansion
When the metal rails in this picture heated up, they increased in length and volume
Thermal Expansion caused the rails to buckle and bend
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9. Unit A : Chapter 1 : Section 1
What is Temperature?
Thermal Expansion
The asphalt in the road expands when heated and contracts when cooled
This results in cracks and potholes due to Thermal Expansion
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10. Unit A : Chapter 1 : Section 1
What is Heat?
Heat- A Transfer of Energy
Heat is the transfer of energy between objects or particles that are at different temperatures
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11. Unit A : Chapter 1 : Section 1
What is Heat?
Heat- A Transfer of Energy
Energy moves from the warmer object to the cooler object until both are the same temperature
This is known as Thermal Equilibrium
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12. Unit A : Chapter 1 : Section 1
What is Heat?
Reaching Thermal Equilibrium
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13. Unit A : Chapter 1 : Section 1
What is Heat?
Energy is Transferred by 3 Methods:
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14. Unit A : Chapter 1 : Section 1
What is Heat?
Conduction is the transfer of thermal energy through direct contact
Hold a metal wire in a flame and energy travels from atom to atom until it burns your hand
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15. Unit A : Chapter 1 : Section 1
What is Heat?
Convection
Convection is the transfer of thermal energy by the movement of a liquid or a gas
Convection is seen as hot material rises and cool material sinks
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16. Unit A : Chapter 1 : Section 1
What is Heat?
Radiation
Radiation is the transfer of energy through matter or space as EM waves, such as visible light and infrared waves
Radiation is the only type of energy transfer where the objects don’t have to touch
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17. Unit A : Chapter 1 : Section 1
Matter & Heat
What Do You Think?
When you get overheated and start to sweat, your body begins to cool off.
Why?
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18. Unit A : Chapter 1 : Section 1
Matter & Heat
States of Matter
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19. Unit A : Chapter 1 : Section 1
Matter & Heat
Ice Crystal
Particles of a solid do not move fast enough to pull apart, so they vibrate in place
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20. Unit A : Chapter 1 : Section 1
Matter & Heat
Melting of Ice
Energy must be transferred to a solid to make it become liquid
The water will remain the same temperature until all of the ice has melted
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21. Unit A : Chapter 1 : Section 1
Matter & Heat
Evaporation of Water
Transfer more energy to the water and its particles move even faster
When the liquid water molecules move fast enough, they become a gas
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22. Unit A : Chapter 1 : Section 1
Matter & Heat
Sweat Cools You Down
When your body gets too hot, you perspire
The liquid sweat uses energy from your body to evaporate water molecules
You get cooler!
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23. Unit A : Chapter 1 : Section 1
Let’s Review!
- 1 -
What is temperature?
Explain what happens when you use a thermometer to measure temperature…
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24. How is radiation different from conduction and convection?
Let’s Review!
- 2 -
How is radiation different from conduction and convection?
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25. Unit A : Chapter 1 : Section 1
Let’s Review!
- 3 -
When water evaporates, the air near the water’s surface becomes cooler.
Why?
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26. Unit A : Chapter 1 : Section 1
Web Sites to Visit:
Harcourt Science: States of Matter
BBC: Science
BrainPop: States of Matter
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27. Unit A : Chapter 1 : Section 1
Pre-AP Extensions
You should be able to explain Thermal Conductivity and Specific Heat Capacity.
You should know what a Calorimeter is and the difference between a calorie (cal) and a Calorie (C)
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