IMPACT CRATERS

Today I did a lab with Emma S. and Lilly. The goal was to see how Gravitational Potential Energy and Kinetic Energy, affected the size of a crater, as well as width nad weight of the asteroid.

We had a box of flour about 1' by 1' with the flour spread about 5 inches deep. We dropped three different sized balls, each ball five times from 2 inches up, 4 inches up, 6 inches up, 8 inches up, and 10 inches up. The three different types of ball we used were ping-pong ball. a marble-like ball, and a golf ball.



Here, the marble, the golf ball, and the ping-pong ball are shown.
Dimensions of the balls:

Ping-Pong: 4 cm. in diameter and 3g. in weight
Marble-like: 2 1/2 cm. in diameter and 10g. in weight
Golf Ball: 4 cm. in diameter and 45g. in weight

These are the kinds of impact craters different balls made, just to give you a sense of how much the flour gave in:



Here are the tables of the sizes of the craters with different balls:







Ping-Pong:

Height Dropped From: Depth of Crater: Diameter of Crater:
2 inches 1 cm. 2 1/2 cm.
4 inches 1 1/4 cm. 3 cm.
6 inches 1 1/2 cm. 3 cm.
8 inches 1 3/4 cm. 3 cm.
10 inches 1 1/2 cm. 3 cm.

Marble-Like Ball:

Height Dropped From: Depth of Crater: Diameter of Crater:
2 inches 2 3/4 cm. 3 cm.
4 inches 2 1/8 cm. 3 1/4 cm.
6 inches 2 3/16 cm. 3 1/2 cm.
8 inches 2 1/2 cm. 3 3/4 cm.
10 inches 3 cm. 3 1/2 cm.

Golf Ball:

Height Dropped From: Depth of Crater: Diameter of Crater:
2 inches 2 1/2 cm. 4 cm.
4 inches 2 3/4 cm. 4 1/2 cm.
6 inches 3 1/4 cm. 4 cm.
8 inches 3 1/2 cm. 4 1/2 cm.
10 inches 3 3/4 cm. 4 3/4 cm.

Here are the (in order) marble-like ball, ping-pong ball, and golf ball height versus diameter of crater and depth of crater graphs. (I couldn't figure out how to change the color line, but for each graph, the line for the diameter is the one with higher y -numerical value):





Energy:

This it true for any object under these circumstances. Before the ball is dropped, as in it is being held in the air, it is all gravitational potential energy (GPE), and any time after that, until the very end, it is a mix of GPE and Kinetic Energy (KE), the sum adding up to the amount of Joules of the GPE at the top. At the split second before it hits the ground, the ball has all KE. GPE is converted into KE by the force of gravity.

When the ball hits the flour, it has all KE, and since KE is the energy of motion, it hits the flour with motion. I think that Newton's Third Law ties into this, "For every action there is an equal and opposite reaction" because as the ball hits the crater, the reaction is flour moving up around the ball causing a deeper crater. The craters are deeper when the ball is dropped from higher, because we know that GPE depends on the height, the higher it was dropped from, the more energy, both GPE and KE it will have. Because it has more energy, it will have larger velocity. When things have a large velocity, they will cause a bigger crater because there is they displace more. (I am a little confused). The diameter also has to do with the velocity at which the ball is landing, but also it just has to do with how wide the ball is. If the ball is dropped from just the right height, half the ball will be buried under the flour, which is the largest diameter you can have. (This is why the diameter on the graph goes up then down.)

I would like to do some kind of lab where we can measure the speed of the object, find the average, and use it to find the amount of GPE and KE the ball has.