Lab 8: Energy and Heat Online Version Introduction 1. Describe what the following terms mean: a. Temperature: b. Heat:

2. Using your definition for temperature above, explain how a thermometer works to provide a visual representation of the temperature.

3. The simulator allows you to add the same amount of heat energy to different materials (e.g. water, oil, iron, brick). If you were able to measure the temperature of these materials as you are heating them, would you predict that each will have the same temperature changes? Explain.

Part 1: Specific Heat For this part of the experiment, you will use the PhET simulation Energy Forms & Changes (https://phet.colorado.edu/sims/html/energy-forms-and-changes/latest/energy-forms-and- changes_en.html) to predict, experiment, discover and interpret the meaning of the material property known as specific heat.

1. Position the Iron block on one of the ring stands and move a thermometer to the block to measure the temperature of it. Then click the Energy Symbols tab and begin increasing the heat under the iron. Describe what you observe.

2. Predict what you would see if you are able to measure the temperature of the Iron block and Brick block as you supply the same amount of heat to each block.

3. Click the reset button, then drag the iron block on one stand and the brick block on the second stand. Again, put a thermometer in both blocks to measure the temperature of each. Click the Energy Symbols and Link Heaters tabs. Before adding any heat to the blocks, observe any differences in the blocks and provide a reason for this.

4. Increase the temperature on the blocks and observe the thermometers and record observations.

5. Repeat the comparison done with the blocks above, this time comparing the two liquids. Record your observations.

6. Repeat again this time comparing water and iron. Records your results.

7. What does your experiment tell you about water?

8. The specific heat (c) of an object tells us how much energy (J) it takes to increase the temperature of an object per kilogram per degree Celsius. We can find it from the question for heat = , where T is the change in temperature and m is the mass of the object. The specific heat of water is 4,184 J/kgC. If you had the temperature from this simulation, how could you find the specific heat of iron?

9. Based on your observations and analysis from above, explain what you would expect to see in this experience if you used copper instead of iron. The specific heat of iron is 460 J/kgC and the specific heat of copper is 376 J/kgC.

Part 2: Latent Heat For this part of the experiment, you will use the PhET simulation States of Matter, States and Phase Changes (https://phet.colorado.edu/sims/html/states-of-matter/latest/states-of- matter_en.html) to predict, experiment, discover and interpret the meaning of the material property known as latent heat.

1. Starting in States, begin with solid water and explain how to make water change to the liquid state and then to the gaseous state.

2. Now start with gaseous water (water vapor) and explain how to make the water change to the liquid state and then to the solid state (ice).

3. When you apply heat energy to a substance, where does the energy go? Think about the law of conservation of energy.

4. The latent heat (L) of an object tells us how much energy (J) per kilogram is necessary to change the phase of an object from solid to liquid (or vice versa) or from liquid to gas (or vice versa), = . The latent heat of fusion (transition from solid to liquid, Lf) of water is 334,000 J/kg, where the freezing temperature for water is 0C. The latent heat of vaporization (transition from liquid to gas, Lv) of water is 2,264,000 J/kg, where the vaporization temperature for water is 100C. If you had an initial mass of water in this experiment, how could you find the heat transferred during each of water's phase changes?

Reflection Questions 1. If you place 0C ice into 0C water in an insulated container, what will happen? Will some ice melt, will more water freeze, or will neither take place?

2. Putting a lid on a boiling pot greatly reduces the heat transfer necessary to keep it boiling. Explain why.

3. Substance A has twice the specific heat of substance B. Equal masses of the two substances, at different temperatures, are placed in thermal contact and allowed to come to equilibrium. a. What is the ratio QA/QB of the energy transferred to the samples? b. What is the ratio TA/TB of their temperature changes?

4. A tile floor may feel uncomfortably cold to your bare feet, but a carpeted floor in an adjoining room at the same temperature feels warm. Why?

5. On a very hot day, it's possible to cook an egg on the hood of a car. Would you select a black car or a white car on which to cook your egg? Why?

6. A person shakes a sealed, insulated bottle containing coffee for a few minutes. What is the change in the temperature of the coffee? a. a large decrease b. a slight decrease c. no change d. a slight increase e. a large increase