Purpose: To investigate the heat absorption and transfer properties of various soils. You will experiment with Earth soils inside and outside. Your results from the outside soil experiment should be compared with data from the Mars Viking Lander 1. You may notice there is not enough information to reach a firm conclusion about the Mars soil measurements. After your Earth soils experiments you will design your own experiment that could be carried on a future Mars mission.

Do this experiment in your classroom under controlled conditions. Heat the soil samples with light bulbs and record the soils' temperatures over time. (This lab is the same as the Outside Soil Test, only done inside the classroom) You will use the Scientific Method to gather information about the possibility of living on Mars.

Observe the soil samples and develop your hypothesis based on your observations and experience with soils. A Data Sheet that you can fill out is also available.

Study the variables so that you will be better able to maintain the controlled variables and keep the experiment valid.

Variables:

• Independent:
• elapsed time (number of minutes)
• type of soil:
• sand
• potting soil
• top soil
• clay
• fill dirt
• Dependent:
• temperature of the soil
• Controlled:
• size of sample
• size of sample containers
• type of sample container
• heat source
• distance from heat source
• depth of thermometer
• type of thermometer
• time between measurements

Materials:

• soil samples
• Styrofoam cups
• plastic wrap
• rubber bands
• thermometer
• light source
• data sheet
• pencil
• stop watch

Procedure:

Set up:

1. Collect soil samples.
2. Fill each cup to the top with a separate sample.
3. Cover tightly with plastic wrap and rubber band.
4. Adjust light source so that each soil sample being heated is the same distance from the light (20 cm is recommended).

Experimentation:

1. Insert thermometer into the side of the cup sample so that the tip of the thermometer is four centimeters from the top surface. Shield the exposed end of the thermometer from the light.
2. Wait until you are certain the thermometer reading stabilizes.Measure and record the starting temperature of the sample.
3. Move the sample under the light source and check the distance from the light to the soil.
4. Turn the light on and start stop watch.
5. Record on Data Sheet the soil temperature every two minutes for at least thirty minutes (15 measurements). You should record until the temperature no longer increases. This may take up to an hour.
6. Repeat for each of the samples.

Results:

Graph your data such that time is on the horizontal axis and temperature is on the vertical axis. Compare your graphs with the graphs of Martian soil.

Conclusion: Now, compare your results with the initial hypotheses.

The second hypothesis WAS/ WAS NOT supported

Explain how the results of this test support, weaken or otherwise affect the initial hypotheses.

What other information about Martian soil would you like to know?

Design an experiment for future Mars missions that would provide additional information about Martian soil that you think would be helpful: