Extend students' understanding by conducting one or more of the following activities.
Follow-up Discussion |
All Sciences    |
Hold a debriefing session in which students share their impressions of the exhibition, their results from their investigations, and the answers they found to the questions they had. Suggest that students use Internet resources to investigate any additional questions. (Refer to the resources section for suggested Web sites.)
Impacts and Cratering |
Physical Science |
This photo of the asteroid Eros was taken by the NEAR spacecraft.
©NASA NEAR
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Students can create impact craters by varying the velocity or mass of a dropped object, and observing and measuring its effects. Place a large shallow baking pan or box on the floor. Fill with 2 inches of flour. Sprinkle a thin layer of cocoa powder over the surface. Drop a marble straight into the pan near the center. Remove the marble and have students examine the crater that was formed and the material that was ejected. Then drop a golf ball and a Superball in different parts of pan from the same height as the marble. Have students compare the craters that result. Fill over the holes and cover with more cocoa if needed. Have students explore cratering by varying the angle and velocity of the balls. Point out that impact craters are formed by the kinetic energy that is released when a moving mass (ball) hits a stationary body (pan). The formula for determining kinetic energy (K) is half the mass (M) of an object times the velocity (v) squared: K=Mv2. The formula for the velocity of the dropped objects is: v = √2gh, where g is gravity and h is the height from which the object was dropped. For the Earth, gravity is constant at 980cm/sec2. Have students calculate the mass of the balls and the kinetic energy that is released when each is dropped.
Heading Off Impacts |
All Sciences |
An artistıs rendering of what might occur when a massive asteroid hits the Earth.
©NASA, Don Davis
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Pose this hypothetical scenario to students: An asteroid (2 km in diameter) is headed to the Earth and will most likely strike the planet in 10 years. You and your team have been asked to prepare a plan to deflect the asteroid. Since the hit would cause immense catastrophe, you have unlimited funds. Have students work in teams to prepare their plans and present them to the class. The class can discusse the merits of each plan and can vote to select the best plan. Students can visit the Nasa Web site Asteroid and Impact Hazards (http://impact.arc.nasa.gov/index.html) to learn what steps are being taken to deter asteroid impacts.
