1. 8.4 – Temperature, Thermal Energy, and Heat
Do you have your chapter out on your desk??

2. Particles in motion – kinetic energy
Temperature is measure of how hot or cold something is compared to reference point.
It is related to the motion of the particles in an object
Kinetic Theory = Matter is composed of particles that are atoms, molecules, or ions that always are in random motion
Particles in motion – kinetic energy
Particles collide and energy is transferred
The faster the particles collide, the more heat(energy) is transferred.

3. Temperature
The temperature of a substance is a measure of the average kinetic energy of its particles
SI unit for temperature is the Kelvin (K)
Other temperature scales – Celsius & Fahrenheit

4. Thermal Energy
Total of the kinetic and potential energies of all the particles in an object
It depends on
Temperature
Number of particles
How particles are arranged
STOP! Complete p302

5. Heat
Heat is thermal energy that flows from something at a higher temperature to something at a lower temperature
Heat is a form of energy
measured in joules
STOP! Complete p303

6. Data Table Water Temperature Observations Room Temperature Hot water
Cold water

7. Heat Energy & Particle Movement Purpose: To demonstrate the motion of particles due to heat
Materials:
3 beakers Ice water Dark food coloring Room temp water
Hot water
Procedure:
1. Fill a small beaker about 2/3 full of room temperature water.
2. Place one drop of dark food coloring on the surface of the water. DO NOT STIR.
3. Observe & record your observations.

8. Fill a second beaker about 2/3 full of ice water.
5. Fill a third beaker 2/3 full of hot water.
6. Place the beakers with the hot and cold water side by side.
7. Wait a minute for the water to stop moving. Then add one drop of food coloring to
each beaker at the same time.
8. Observe and record.
Conclusion: In your own words, explain what happened.

9. Let’s Discuss…
Two glasses of water have the same thermal energy. Must they have the same temperature? Explain.
Describe what is meant by absolute zero (use your definitions).
Discuss the three things that determine thermal energy.

10. Challenging…
Object A has less thermal energy than Object B, but heat flows from Object A to Object B. What conditions would make this possible?
Answer: Object B must contain many more particles. This way it still has a greater thermal energy

11. 8.5 The Transfer of Heat
Let’s talk about My Planet Diary… p304

12. How Is Heat Transferred??
Remember: Heat moves from warmer areas to cooler areas through…
Convection
Conduction
Radiation

13. Convection
Convection is heat transfer that occurs only in fluids, such as water and air.
Heated air is less dense than cooler air, so it rises above the cooler air.
Cooler air is now forced down, where it is and then rises.
This flow is known as convection currents.
Can you think of examples??

14. Conduction
Conduction transfers heat from one particle of matter to another.
The fast moving particles collide with the slower moving particles causing them to speed up (heat up).
What are some examples??

15. Radiation
Radiation is the transfer of energy by electromagnetic waves.
It is the ONLY form of heat transfer that does NOT require matter.
What examples do we experience every day??
STOP!! Complete pp306 and 307

16. Let’s Discuss… Determine what type of heat is transferred…
1. an entire lake is heated by water from a hot spring at the bottom of the lake…
Convection
2. sunlight melts a wax crayon left outside…
Radiation

17. 3. a burner on a stove heats the bottom of a pan…
Conduction
4. the inside frame of your front door feels cold during winter…
5. a kite rises high above a hot, sandy beach…
Convection
6. you feel the warm glow of a bonfire…
Radiation