Make a list of criteria for younger craters on the board. Students should use what they learned from the last trial and the list of criteria on the board, to determine the relative ages of the new craters. Have students view actual moon pictures and map out areas on the moon's surface where it is possible to determine the sequence of impact crater formation. If time and materials allow further investigation, a set of observations can be made from an object hitting the surface at an angle and traveling at low speed, like a cannonball. While this provides an interesting investigation, it is not relevant to impact craters.
Most meteorites explode upon impact with the Earth's surface.
This explains why most craters are circular. This assures that the marbles hit with the same amount of force. The amount of force applied will not be consistent, which makes comparison difficult and there are safety concerns. Hold the launch ramp at approximately a 45 degree angle to the table top so that the marble will land near the center of the pan. Release the marble 20 cm.