# We can work on Prelab

Answer these questions:1. What factors could affect an impact crater’s shape and size? Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.

2. What effect do you expect varying these factors will have on the craters? Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.

3. Explain how you could test these hypotheses. Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.

One look at the surface of the Moon should convince you that “empty space” is not so empty after all. There is actually a wide range of objects floating between the planets, from tiny particles to asteroids that can be a hundred miles across, debris left behind when the planets were formed. These objects can be perturbed from their orbits (by a close passage by a planet, a passing star, any number of things) and onto paths that cross ours — or any other planet or moon. When that happens, a collision occurs and an impact crater is formed.The size and shape of the crater depend on the impactor: its size, shape, speed, and the angle is hits the ground with. Specifically, the size of the crater depends on the energy of the impactor. However, the relationship is not linear, but rather is a power law:Â Â where D is the diameter, E is the energy of the impactor when it hits the ground, n is the power, and k is a constant.The energy when the impactor strikes the ground is all kinetic,Â where m is the mass of the impactor, and v is the speed it’s going when it hits the sand. Unfortunately, v is inconvenient to measure in our classroom. Fortunately, energy is conserved, so we can give the impactor a known energy and know it will hit the sand with that amount of energy. The total energy of a falling object is the sum of the kinetic and potential energy. If you drop the impactor so it starts with v = 0, the total energy is just potential (called gravitational potential energy):Â where m is still the mass, g is the acceleration due to gravity = 9.81m/s2 at the surface of the Earth, and h is the height above the ground.

Activity #1 Questions:Â 1. As you dropped the marbles from different heights, how did the ejecta (material tossed out of the crater) change?Â Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.

2. When you dropped non-spherical objects, or threw the marble at an angle, how did the shape and ejecta change? How does this relate to craters seen on other planets/moons? Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.

3. If you change the velocity at which an abject is thrown down, how does it impact the crater depth? Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.

4. Describe the transformation of energy that takes place during the formation of an impact crater (from approach of the meteorite to after the crater is formed). Answer based on an appropriate formula/equation. Without the support of the formula, any answer is worthless, and will be graded as â0â.