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Laboratory Activity #2:PHYS
Energy Forms & Changes Virtual Lab
BIO BATCH 18
Introduction: You will use the PhET simulation Energy Forms & Changes to predict, experiment, discover and interpret the meaning of the material property known as Specific Heat Capacity. Warm-Up:
1. Describe what the following terms mean SOLUTION : Temperature - is a measure of the average kinetic energy of the particles in an object. When temperature increases, the motion of these particles also increases. It's not a terrible definition, but it's not the best either .... The temperature is related to the average kinetic energy not the total kinetic energy. Heat - - heat seen as a form of energy arising from the random motion of the molecules of bodies, which may be transferred by conduction, convection, or radiation.
2. Using your definition for temperature above, explain how a thermometer works to provide a visual representation of the temperature SOLUTION: A thermometer measures temperature through a glass tube sealed with mercury that expands or contracts as the temperature rises or falls ...... As temperatures rise, the mercury-filled bulb expands into the capillary tube. Its rate of expansion is calibrated on the glass scale. 3. Thermometers in the past were filled with mercury but most are now filled with alcohol instead due to safety reasons. Why do you think alcohol is used instead or water? SOLUTION: Most thermometers would use mercury, but some use because of its freezing points. Alcohol freezes at - 114 Celsius, while water freezes at 0 Celsius. If it was freezing outside, the water would freeze too, making the thermometer useless. The reason we use alcohol instead of water is that alcohol has a lower freezing point (-114°C) than water (0°C). Also, alcohol doesn't condensate on the top unlike water, which makes the reading of the thermometer easier to read. 4. The simulator allows you to add the same amount of heat energy to different materials e.g. water, oil, iron, brick. If you are 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. SOLUTION:
7. 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 SOLUTION : The block of iron has higher energy level than the brick block, as I apply heat to the two blocks (iron and the brick) I observed that the block of brick heats faster because the thermometer rise faster under the block of brick than the block of iron. Observation & Analysis : 8. Increase the temperature on the blocks and observe the thermometers and record observations SOLUTION : As we increase the temperature on the blocks I observe that the thermometer also rises. Brick block has lower internal energy than iron block. During heating, we observe that Brick block has a faster rate of increase in temperature than iron block as seen on the thermometer when both blocks are provided the same amount of heat 9. If you wanted to use these experiment to get quantitative observations and create a graph showing trends, list the variables in such an experiment
SOLUTION :
Independent - time Dependent – energy Control - temperature
10. Repeat the comparison done with the blocks above, this time comparing the two liquids. Record your observations. SOLUTION : Water has higher thermal energy level than the olive oil before increasing heat, but the temperature of the olive oil increases faster as the heat increases. 11. Repeat again this time comparing water and iron. Records your results. SOLUTION : The thermal Energy level of the water is higher than the block of wood. 12. What does your experiment tell you about water? SOLUTION : The experiment imply that water has higher specific heat capacity. Discussion: Specific Heat Capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass e.g. 1 g. It is essentially a property of a material that describes its ability to store heat. Different materials have different specific heat capacities.
SOLUTION :
A Iglo has an efficient choice for designing a shelter in a cold climate, Because ice's thermal conductivity is low, like the thermal conductivity of air, an igloo works by stopping heat being transferred into the surroundings, even when the temperature is really low. The ice and the still, unmoving air both act as highly effective insulators.
