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Heat Transfer? Can you Measure it? How is it Done?

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Author: Dr. Muriel Gerhard
Topics: High School, Physics

Grade Level: 9th - 12th; Type: Physics

Objective:

To determine how one can measure the transfer of heat?

Research Questions:

  • In your experiment, why is it important to use foam cups? In your experiment, what are some possible sources of heat loss?
  • How can they affect your results?

On the information level, this experiment serves to acquaint students with basic information on the process of heat transfer and the conditions under which the transfer will occur. It becomes evident that heat is energy that flows between two objects as a result of a difference in temperature. In brief, heat flows from a warmer body to a cooler body. Heat also moves as a result of direct contact as well as by processes such as convection and radiation. The student also learns about the specific heat of different materials. When heat flows into an object its thermal energy increases and so does its temperature. The amount of heat depends on the size of the object and the material of which it is made. The student is learning about the specific heat of the various materials used in this project recognizing that the specific heat of any substance is defined as the amount of energy that must be added to the material to raise the temperature of a unit mass by one temperature unit. In performing this experiment the concepts are being internalized. They are “seeing” the specific heat of different materials.

This science fair experiment also serves to acquaint students with the essential processes of sciencing such as the importance of the use of a control when required, of identifying dependent and independent variables, of selecting a large enough sample of subjects when applicable to the objective, of accurate and organized data collection, of pictorial and or graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. They take on the role of scientists and in the process they learn to act as scientist.

Materials:

  • 2 plastic foam cups
  • a pen
  • a pencil
  • a thermometer(Celsius)
  • tongs
  • a Bunsen burner or a large can of sterno
  • a large pot
  • a bolt
  • a paper clip
  • a clock with a second`s hand

These materials can readily be obtained from a local hardware store and from home.

Experimental Procedure:

  1. Gather all of the materials that you need for your project.
  2. Put on your safety glasses, apron and gloves.
  3. Reproduce the chart provided on the next page so that you can readily record your observations.
  4. Exercise care if you are using a Bunsen burner in lieu of a stove and have long hair tie it back!
  5. Start with the cups and label them #1 and #2.
  6. Using the graduated cylinder, Start by measuring 75 mol of tap water and and put it into the cup#1
  7. With a sharp pencil make a small hole on the rim of cup#2.Place the thermometer carefully into the hole.
  8. Now place cup # 2 upside down on top of cup#1 so that the rims meet and matctch. Make certain that the thermometer is in the water in cup #1.
  9. Record the temperature of the water in your data chart.
  10. Light the Bunsen burner or the large sterno can. Take the bolt, use tongs, and hold it in the flame for ten seconds.
  11. Now, carefully, remove cup#2 and put the hot bolt gingerly into the water in cup#1 and cover with cup#2. Read the temperature of the water.
  12. Wait for 30 seconds, read the temperature again. Record the temperature that was the highest in your data chart.
  13. Replace the water in cup#1 with tap water. Start again repeat steps 8 through 12 using the nut and then the paper clip.
  14. Use the formula heat = mass of the water X temperature change X specific heat. With the specific heat of water being 4186 J/kg times degrees C.
  15. Review your data. Explain why the temperature of the water rose. What were your results with the nut and the paper clip? How do you explain these results?
  16. Write up your report. Make certain that you include your research and your bibliography.                                                    

                                                        Chart for Data Collection 

Objects Heated Mass of H2O Initial Temp Final Temp Change in Temp Heat Transferred
Iron bolt          
Iron nut          
Paper clip          

 

Terms/Concepts: Heat, thermal energy, specific heat, conduction, convection, radiation.

References:

Lafferty,Peter. Burning and Melting . New York: Gloucester Press, 1990 Heat.Mac, Dos. ESI.

 

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