The NASA SCIence Files™
Great Balls of Fire!

Purpose: Students will investigate meteor impacts on the Earth’s surface

Materials

Procedure

  1. Place the pan on the floor and fill the pan with sand.
  2. Use a balance to find the mass of each ball and record in the data chart below.
  3. Use the meter stick to measure a height of 30 cm from the top of the sand.
  4. Hold the golf ball at the 30 cm mark and drop it into the sand.
  5. Observe the impact made by the golf ball and record your observations in your science journal.
  6. Carefully remove the golf ball and measure the diameter of the circle created in cm. Record in the data chart below.
  7. Use the side of the ruler to flatten and level the surface of the sand.
  8. Repeat steps 2-6 for two more trials. Make sure the dropping height remains constant.
  9. Repeat steps 2-7 for the other two balls.
  10. Find the average diameter for each ball.
  11. Create a graph or spreadsheet showing the results for each ball.
  12. Repeat steps 2-11 but increase the height to 100 cm (1 m) that the balls are dropped from.
  13. Compare and contrast the results for each of the balls at the different heights.
  14. Discuss the results with the class.

Data Chart

Conclusion

  1. When you compare and contrast the sizes of the craters made by the different objects what similarities and differences are there?
  2. What happens to the size of the crater when you change the height of the object that was dropped? Why?
  3. Do you think it is possible to predict how big a crater will be if you know the size of the meteorite that will be landing on the surface? Why?
  4. Since meteorites often explode at or near the surface, how would the explosion affect impact crater formation?

Extension

  1. Note: A dust mask should be used when sprinkling paint. Using a strainer or sifter, sprinkle a thin layer of red powdered tempera paint over the sand. Place another very thin layer of flour or other dry material over the top of the tempera paint, just enough to conceal the paint. The tempera paint and flour represent the loose soil above the bedrock and it will allow the students to better observe the impact crater and its ejecta and rim. Look for patterns in the dispersion of the paint and flower upon impact. Have students sketch what they see in their science journal.
  2. If time permits, discuss rocks and how to determine their relative age in a crater. Note that the older rocks would be found deep within the crater while the younger rocks would be around the rim of the crater. Ask the students to explain why.
  3. Use three same sized objects that are of different masses and compare the impact craters or use different objects such as marbles or ball bearings.
  4. To simulate what happened on the Moon and Earth’s surface millions of years ago, drop many different sized objects at various heights and angles. Do not level the sand after each drop. After completing all the impacts, discuss how the surface looks and compare the surface of the Moon today compared to the surface of the Earth. Note that Earth’s craters have eroded over time while the Moon does not experience erosion since there is no atmosphere on the Moon.