Welcome to this experimental science test. We hope that you will find it interesting and worthwhile. Carefully read through these directions and the directions on the next page before you begin to work.

You may be part of a group for the first part of this exercise. Each group should carry out the experiment and collect the data together, but each student must record the data in his or her own booklet. Be sure to record the data exactly as you observe them. After the data have been collected, each student should answer the questions independently.

After you have finished your experiment and have recorded all of the data, you will be asked to answer some questions about the experiment and the data you recorded. Your answers must be written in this test booklet in the space provided. Make sure that you understand each question before you begin to write. At any time while you are writing your answers, you may look back at the directions for the experiment and the data you collected. Be sure that your answers are written as clearly and neatly as possible.

Before you turn the page, read the list of materials given below and check to make sure that your group has everything listed.

You and your lab team have been hired by a group of architects to help them design a solar home. The architects have asked you to help them select the material that will be used as the heat mass. The heat mass is a large amount of material, usually in a wall or on the roof, that is efficient in converting sunlight into heat energy. The heat energy is stored in the wall and then slowly reradiated into the home during the cool evening hours. The architects have asked your lab team to test the following materials: water, sand, gravel, and Styrofoam. You will conduct the tests as a group but each member of the group will individually record and analyze the data and make a recommendation to the architects.

You will be working with three other students to collect data. Each member of the team will collect data for a different material: water, sand, gravel, or Styrofoam. Each student must record the data for all four materials in his or her own booklet.

1. Fill your 250 ml cup with one of the four substances. The material should be level with the top of the cup.

2. Insert a thermometer into the material. The thermometer will remain in the material throughout the experiment. DO NOT REMOVE IT! The thermometer's mercury or alcohol level must extend above the material, so that you can read the temperature during the experiment, as shown in Figure 1 below. DO NOT TURN ON THE LAMP!

3. Each cup should be placed on one of the Xs that is marked on the workbench. The four Xs are the same distance from the bulb. The bulb should be about 30 cm above the table top.

4. Measure and record the temperature of your material (the initial temperature) in Table 1. (Note: Each thermometer in the four cups should be pushed down to the same depth).

5. Turn on the bulb and leave it on for 10 minutes.

6. After 10 minutes, turn off the bulb and immediately record the temperature inside your cup. This temperature will be designated T0.

7. Allow each of the materials to cool naturally. Two minutes after the lamp is turned off, measure the temperature (T2) and record it in Table 1. To obtain temperatures T4, T6, T8, and T10, record the temperatures every 2 minutes after the lamp is off. This should take 10 minutes.

8. Each member of the group must record the data in his or her own booklet.

Please answer the following questions by yourself.

1. Using a different colored pencil for the graph of each material, plot the data for water, gravel, sand, and Styrofoam. If you do not have colored pencils, use different kinds of lines, e.g., dashes, dots, or squares, for each graph (- - - - n n n n  H H H H  s s s s).

2. How many degrees (°C) did each substance cool during the 10-minute cool down period?

Water: _____________ ;  Sand: _____________ ;  Gravel: _____________ ;  Styrofoam: _____________

Which material cooled the fastest? __________________________________________________________

Which material cooled the slowest? _________________________________________________________

3. Based on the data, which material would you recommend for use as the heat mass of this solar home? Explain to the architect why you have selected this material.