Topic 2:Measuring Temperature

Some good resources:

How thermometers work

Temperature conversion table

1. What are all substances made of?
2. What happens to a substance when thermal energy (heat) is added ?
3. Explain what you think would happen when thermal energy is removed from a substance?
4. Draw 3 boxes of the same size. Using the simulation of Temperature and kinetic energy, draw what is happening to particles at 0 degrees Kelvin, 500 degrees Kelvin and 990 degrees Kelvin. Arrows might help to indicate what is happening.
5. Describe in your own words what kinetic energy is.
6. Either describe or draw how particles are arranged for a solid, a liquid and a gas.
7. Describe the particle model of matter (page 203 in SciencFocus 7).

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• James Joule
• Anders Celcius
• Lord Kelvin

4. How is thermal energy different from temperature? (Hint: you have studied three answers to this question so far - a) definitions b) which can be measured directly and which can not? c) what are the SI units of measure for thermal energy and temperature?)

5. Modern scientists do not use Lavoisier's "caloric fluid" theory (page 204). If this theory is wrong, why do you suppose it is discussed in many science text books?

6. Can energy be created or destroyed? Give reasons for your answer.

• energy redefined (page 204)
• thermal energy (page 205): see notes below
• kinetic energy
• particle theory
• states of matter: see review notes below
• expansion
• contraction
• volume
• joules (page 205)
• temperature redefined (page 204)

Statements about the Particle Theory of Matter:

1. All particles of the same substance behave the same way.

2. The particles are in constant motion (except at -273 degrees Celsius), that is, they have kinetic energy.

3. There are spaces between the particles:

• the spaces increase with the addition of heat creating an increase in volume.
• the spaces decrease with the removal of heat creating a decrease in volume.

4. Attractive forces (bonds) exist between particles.

• bonds decrease or break with the addition of heat.
• bonds increase with the removal of heat.

Example of Total Kinetic Energy

Heat energy discribes the kinetic energy of particles of matter. To understand how matter changes temperature and what this change means, we should use the scientific meaning of the terms thermal energy, heat and temperature.

The thermal energy of substance is the total kinetic energy of all the particles the substance contains. If you measure the thermal energy of a cup of hot water, for example, you would be measuring the total amount of kinetic energy of all the water particles in the cup. If you have a large pot of hot water, and you measure the temperature, it may be the same as the cup of water, but the pot of hot water has MORE thermal energy because the amount of volume is more and therefore there are more particles. If you added up the kinetic energy of all water particles in the pot, you would find that it was greater than the total kinetic energy of the particles in the cup.