PURPOSE: To illustrate how a crater forms as a result of an impact or a blast from below.

DESCRIPTION: (1) Drop a steel ball onto a dish of sand. The ball becomes partially buried and a crater forms.

(2) Bury the end of the hose from a can of compressed air in the sand and smooth out the sand. Give a blast of air from the can and notice the crater that forms.

A generation ago there was a debate among geologists and astronomers as to the origin of lunar and terrestrial craters. This demonstration illustrates two ways in which craters can form.


REFERENCES: (PIRA 8A20.20, 8A30.10)

EQUIPMENT: Dish of fine sand, steel ball, tube attached to compressed air, video camera for TV projection if necessary.

SETUP TIME: 5 min.

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