Purpose: To investigate the heat absorption and transfer properties of various soils. You will experiment with Earth soils. You will compare your results with the Mars observations. ( You may notice there is not enough information to formulate a good hypothesis or reach a firm conclusion. ) The Martian data included here were collected under different conditions and for a different purpose. After your Earth soils experiments you will design your own experiment that could be carried on a future Mars mission.

Do this experiment outside under controlled conditions. Select a day when clear skies are forecast. Place the cups in a location which is not shaded during the day one day prior to reading the temperatures. Read the temperatures at the same intervals as the inside experiment. Begin as early in the morning and continue until as late as possible. (This lab is similar to the Inside Soil Test, only done outside 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. Find a place outside for each sample so they will be exposed to the sunshine throughout the entire day.

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 direct sunlight.
2. Take the samples outside but keep them shaded from the Sun. Wait until you are certain the thermometer reading stabilizes. Read and record the starting temperature of the sample.
3. Expose the soils to the Sun and record the time.
4. Record on Data Sheet the soil temperature at regular intervals (about twenty to sixty minutes). Record for at least three days.
5. 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: