1. Warm-Up Exercise Week 2 1/16/13
You walk into the bathroom in your bare feet. The temperature in there is 23 degrees Celsius. You step onto the tile floor and it feels very cold. Quickly, you step onto the throw rug in front of the sink, and the rug feels warmer.
Is the floor really colder than the rug?
Why do they seem to be at different temperatures when your bare feet touch them?

2. How is heat transferred through matter and space?
Essential Question
How is heat transferred through matter and space?

3. Ice-Cold Lemonade
It was a hot summer day. Mattie poured herself a glass of lemonade. The lemonade was warm, so Mattie put some ice in the glass. After 10 minutes, Mattie noticed that the ice was melting and the lemonade was cold. She had 3 different ideas. Which idea do you think best explains why the lemonade got cold?
The coldness from the ice moved into the lemonade.
The heat from the lemonade moved into the ice.
The coldness and the heat moved back and forth until the lemonade cooled off.

4. ANSWER B The heat from the lemonade moved into the ice.
As the molecules in the warmer lemonade came in contact with the molecules in the cooler ice, heat energy flowed into the ice from the lemonade.
This process cooled the lemonade and melted the ice.

5. High-Low Song High-Low, High-Low, That’s the way the heat will flow.
(whistle)

6. Thermal Energy
All matter is made up of constantly moving particles. All moving things possess kinetic energy.

7. Temperature
Temperature is a measure of the average kinetic energy of the particles in a sample of matter.

8. Temperature
As the particles in a sample move faster and faster, the kinetic energy becomes greater and the temperature of the object rises.

9. Temperature

10. Thermal Energy
Thermal energy is the total energy of the particles in a material. This total includes:
Kinetic energy – vibrations and movement within and between particles
Potential energy – forces that act within or between the particles (bonds)

11. Thermal Energy Thermal energy depends on:
Mass – the greater the mass, the larger the number of moving particles
Temperature – the higher the temperature, the faster the particles are moving

12. Thermal Energy
Example – Temperature as a factor

13. Thermal Energy
Example –Mass as a factor

14. HEAT
Heat is the thermal energy that flows from something with a higher temperature to something with a lower temperature. In most cases, heat flows from warmer to cooler materials.

15. HEAT
Thermal energy travels as heat from a material of higher temperature to a material of lower temperature.
Energy is transferred from your back to the stethoscope because your back has a higher temperature (about 37°C) than the stethoscope (probably room temperature, about 20°C) has. This energy is transferred quickly, so the stethoscope feels cold to you.

16. What is the difference between Temperature & Heat?
Heat vs. Temperature Video

17. Heat vs. Temperature Temperature Heat Degree of Hotness
Based on Speed of molecules
Heat
Quantity of Hotness
Based on Speed and Mass

18. Warm-up (Week 2) 1/20/12
In 3 sentences, write what is happening when your hand touches the table as it relates to HEAT TRANSFER..

19. Warm-up Activity (Week 2) 1/20/12
Copy the following statements and write True or False
1. Thermal Energy depends partly on the temperature of a substance.
2. A cup of water at 283 K and a pot of water at 283 K have the same thermal energy.

20. Transfer by Collisions
Methods of
Thermal Energy Movement
Method #1
Conduction – transfer of thermal energy through matter by direct contact of particles
Transfer by Collisions

21. Thermal Energy Movement
Methods of
Thermal Energy Movement
Conduction can take place in solids, liquids and gases.

22. Thermal Energy Movement
Methods of
Thermal Energy Movement
Matter must be present for conduction to take place!

23. Thermal Energy Movement
Methods of
Thermal Energy Movement
Examples:
Heating a pan on a stove (pan heats up by conduction) or place a spoon in a bowl of soup (spoon heats up by conduction)
The end of this spoon will warm up because conduction, the transfer of energy through direct contact, occurs all the way up the handle.

24. Thermal Energy Movement
Methods of
Thermal Energy Movement
Method #2
Convection – transfer of thermal energy by bulk movement of matter

25. Method #2
Transfer by currents

26. Thermal Energy Movement
Methods of
Thermal Energy Movement
Convection can take place in fluids (materials that flow). Liquids and gases are fluids. Currents carry less dense, warmer material up while cooler, denser material sinks.

27. Thermal Energy Movement
Methods of
Thermal Energy Movement
Matter must be present for convection to take place!

28. Thermal Energy Movement
Methods of
Thermal Energy Movement
Examples:
Ocean currents, wind, boiling water
The repeated rising and sinking of water during boiling are due to convection.

29. Thermal Energy Movement
Methods of
Thermal Energy Movement
Method #3
Radiation – transfer of thermal energy in the form of waves.

30. Thermal Energy Movement
Methods of
Thermal Energy Movement
Energy that travels by radiation is often called radiant energy. Only radiant energy that is absorbed changes into thermal energy.
Examples: Microwave heating food, sun’s energy heating a sidewalk
The coils of this portable heater warm a room partly by radiating visible light and infrared waves.

31. Thermal Energy Movement
Methods of
Thermal Energy Movement
Different materials absorb radiant energy differently.
Material Effect
Shiny ________________
Dull ________________
Dark colors ________________
Light colors ________________

32. Thermal Energy Movement
Methods of
Thermal Energy Movement
Different materials absorb radiant energy differently.
Material Effect
Shiny Reflects radiant energy
Dull Absorbs radiant energy
Dark colors Absorbs radiant energy
Light colors Reflects radiant energy

33. Thermal Energy Flow
Conductor – material with many free electrons that can easily transport kinetic energy.
Examples: Metals

34. Thermal Energy Flow
Insulator – material that does not allow heat to move easily through it
Examples: Wood, plastic, air

35. The End