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When you come in…
1. Complete entry ticket
2. Copy down today’s homework
3. Take out the Greenhouse effect worksheet, heat study guide and heat technology poster
You park your car outside on a hot summer day. When you put on your seat belt, what do you feel?
The metal part gets hot enough
to burn you! The cloth stays
cool.
Specific Heat Capacity
Textbook definition: The amount of energy needed to change the temp. of 1 kg of a substance by 1˚ C.
In my own words: How easily something changes temperature.
High specific heat = hard to change its temp.Low specific heat = easy to change its temp.
Which one has the highest specific heat capacity?
Substance Specific Heat Capacity (J/kg °C)Lead 128
Gold 129
Silver 234
Metal of seat belt 500
Aluminum 899
Sand 800
Cloth of seat belt 1,340
Wood 1,760
Water 4,184
Example of specific heat capacity:
Why is it cooler at the beach in the summer?
Hint: Which has the higher specific heat capacity: the water or the sand?
Answer: Water has a high specific heat capacity, so the water stays cool longer than the land.
Heat Technology Refrigerators- Cooling
Takes Energy!
The refrigerator transfers thermal energy from inside the refrigerator to the condenser coils at the back.
This is why the back of a refrigerator feels warm!
Heat PumpsDevices that move thermal energy
from one location to another.
Example: Air Conditioner
Moves thermal energy from inside the house to the
outside
Wait? Doesn’t that go against the rule that heat always moves from hotter to colder?
Air conditioner
Answer: Yes, so it takes energy to do it!
Heat Engines – Machines that use heat to do work. They convert thermal energy into kinetic energy.
Heat Engines
Internal External
Internal Combustion Engine- Fuel burns inside the engine in chambers called cylinders.
Example: car engine