Name Class Date
Thermal Energy “Heat” Lab
Background information: Temperature is the measure of how much thermal energy there is in a substance and thermometers are instruments used to measure this energy. Heat is the transfer of thermal energy from one substance to another. This transfer always travels from the warmer substance to the cooler substance. The transfer of thermal energy can occur in three ways: by conduction, by convection, or by radiation. Conduction is a transfer of thermal energy by direct contact, or touching. Convection is a transfer of thermal energy by the movement of fluids, like water or air. Radiation is the transfer of thermal energy by electromagnetic waves, such as energy from the sun. Conductors are materials that allow thermal energy to be transferred easily while insulators do not allow thermal energy to be transferred easily.
Objective: To identify and measure heat transfers during the boiling of a liquid.
To determine what happens to the heat transfer as substances are added to liquids.
To determine what happens to liquids when they reach the boiling point.
Hypothesis: If a substance, such as salt, is placed in a liquid then the boiling point of the liquid will (increase/decrease/remain the same) because
Materials: (Fill in list of materials used)
Procedure: 1. Follow all SAFETY RULES.
2. Assemble equipment according to the diagram on the board. Draw and label a diagram of your setup below.
3. In a beaker place exactly 200 mL of water.
4. Insert thermometer, wait 2 minutes, and record starting temperature of water sample.
5. Turn hot plate on to setting of 10 and record temperature every minute until rapid boiling occurs. Also record any observations you make.
6. Continue to record the temperature for another 5 minutes after boiling starts.
7. Turn off hot plate.
8. Repeat steps 3 through 7 for your second water sample containing a solute (salt water).
9. Graph your data in a double line graph.
10. Formulate your conclusion.
11. Answer questions.
12. Write summary.
Data:
Starting Temperature of liquids:
Water Salt water
Time (in minutes) / Temperature of Water (in oC) and Observations / Temperature of Salt Water (in oC) and Observations0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Boiling point temperature:
Water Salt water
Conclusion: (State if your hypothesis’ were correct or not and support your conclusion).
Conclusion Questions:
1. Where in your setup was their conduction of thermal energy?
2. In your diagram of the set up label where you have conduction.
3. Where in your setup was their convection of thermal energy?
4. In your diagram of the set up label where you have convection.
5. Where in your setup was their radiation of thermal energy?
6. In your diagram of the set up label where you have radiation.
7. Describe what happened when you placed the cold dye into the warm water.
8. Describe the energy transfers involved with the water and the dye.
9. Describe what happens to the temperature of the liquid when it reaches the boiling point?
10. Based on your results, explain what adding a solute (salt) does to the boiling point of a liquid and why you think this occurs.
11. Why are the boiling points of water and salt different?
12. Look at your graph. Identify which time frame on your graph shows increasing kinetic energy and explain how you can tell.
Summary: (Write a 3 paragraph summary using our standard format).
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