Teacher Feature

Student Objectives:
Students will be able to relate shape and size of crater to size and speed of impactor, and surface composition

Background Information:
In previous sections, we examined images of the Galilean satellites taken by the Galileo spacecraft. Such images will be returned until the end of 1999, and scientists will be busy for years to come analyzing them. These data can be compared to what we already know about the Earth and the terrestrial planets, and we can use it to learn about the physical properties and geologic history of the satellites of Jupiter. We have previously examined the agents of change present on the Galilean satellites. However, there is much more we can tell about these worlds merely by carefully inspecting images of them. There are numerous things we can measure or determine by looking at images of craters of the surfaces of the Galilean satellites (or any planet). Crater depth and diameter provide information about the strength of surface materials, the impactor size and speed; crater shape relates to the structure of the surface material and its composition. The size distribution of craters within an image allows for estimations of the age of the surface.

Lesson Format:
worksheet and discussion

Introduction:
Have students summarize results of cratering lab: A. How are craters made?

Class Activity:
de"Terminator"

Type:
worksheet

Materials Needed:
copies of worksheet, cratering lab results

Procedures:
Have students complete worksheet (either individually or in groups).
Answers are then shared and defended.

Evaluations:
All students complete worksheet and can defend their answers

Other Activities, Misc. Information, etc.:
For younger students, move words to bottom and have students cut and paste
Create an 8-frame comic of de-Terminator showing the results of each type of determiner.