Student Worksheet: Soil Sample Analysis

Answer these questions, based upon your observations of the two soil samples.

1. How can you tell that something you are looking at is alive?
2. How can you tell that something you are looking at is dead, but was once living?
3. How can you tell that something you are looking at was never alive?
4. What did adding water to the soil do? Did this make it easier for you to tell if life was present in some cases? Why?
5. How would your answers be different if you had only a single close-up photograph of soil to study, as may be the case with a spaceship? Would it help if the photograph was in color rather than black and white?
6. Based upon your observations of the two soil samples, is there life on Earth? Why?
7. If you had only seen Earth Sample # 1, and only looked at it when it was dry, would you have known that there was life on Earth? Why or why not?
8. As an extraterrestrial scientist, what can you conclude about life on planet Earth?
9. Which of the two soil samples you saw do you think is most like soil on Mars? (Neither? Both?) Why? Which is most like Venus? (Neither? Both?) Why?
10. From your recent experiences, speculate about Earth scientists' ability to detect life on Mars and Venus.