An impact site may also be surrounded by an ejector blanket. This is a layer of material thrown out by the formation of a crater.
Lighter bits of ground material
If the material is light, e.g. sand, the crater walls may collapse – dependant on the ball size.
Top view: -
There may be several rings formed, I will measure the diameter from the edges of the crater.
Variables: - The variables I could have changed during the experiment must be kept constant throughout;
- The weight of the ball must be the same for each drop, to ensure this happened; the same ball was used every time.
- For the test to be fair, no force should be applied to the ball when dropped. I dropped the ball using the same technique each time, making sure minimal force was subjected to the ball.
- When the ball has been dropped it must be treated the same every time. I very carefully removed the ball from the crater every time, without affecting the size of the diameter. I also measured the crater from top to bottom throughout, so my results were fair.
- Similarly, the sand must be treated the same every time the crater had been measured. Using a ruler I flattened the sand until it was smooth and level.
The variable that I am going to change during the investigation is;
- The height of the ball when dropped, this way I am able to see what the affects are when the ball is dropped from greater distances.
Apparatus: - The apparatus consists of;
- A sand box
- A metre ruler
- A ball
- A small ruler to measure results
- A clamp stand
Diagram: -
Prediction:- I predict that the higher the point in which the ball is dropped, the larger the size of the crater. This is because at a higher point there is more gravitational potential energy. When the ball hits the ground all of the potential energy is converted into kinetic energy. If the potential energy is bigger, therefore the kinetic energy is bigger when the ball reaches the sand, resulting in the crater having a large size diameter.
Also, when the ball is dropped from a higher point, there is more time for the object to increase in speed and velocity. This increase in speed will cause the ball to hit the ground harder. As the sand is pushed down it has nowhere else to go but out, this means the diameter of the crater increases.
To calculate the speed in which the marble ball hits the ground. I would use the formula:
V = 2 x g x h. Where V = velocity, 9 = 10 and h = height.
The ball has relatively small potential energy, meaning the kinetic energy at the surface is small therefore the crater is small.
The ball has a high greater potential energy and kinetic energy at the ground meaning the diameter of the crater will be bigger.
Method:- The method I will use is as follows:
- Collect all of the apparatus and set up the equipment as shown in the diagram.
- Hold the ball at the specific height in which you intend to begin the experiment at, in this case 10 cm.
- Drop the ball without applying any force. This is very difficult and needs to be done with great care.
- Again, being very careful, remove the ball from the crater ensuring the diameter is not affected in any way.
- Using a small ruler, measure the diameter of the crater from top to bottom, measuring from the outer edges that have been formed.
- Record the results on a table.
- After each drop, smooth the sound down before dropping again.
- Drop the ball from the ruler, going up 10 cm each time, following the same procedures.
- Repeat the experiment to get a wide range of results.
Results:-
First set:
Conclusion:- As I predicted, both my graph and results show the higher the drop point the larger the diameter of the crater. This is due to the gravitational potential energy being bigger at a higher point. All of the gravitational potential energy is converted into kinetic energy when the ball reaches the surface, resulting in a larger crater. If the crater is larger, the diameter is bigger. Due to the gravitational potential energy being lower at a smaller height, the kinetic energy at the ground is less. Consequently the crater is relatively small compared to one created from a higher dropped ball.
Evaluation:- I feel my investigation went well, with both my experiments my results followed a pattern which agreed with my prediction, giving me a clear conclusion. The minority of results that didn’t fit the trend my have been due to:
- Accidental force placed on the ball when dropped.
- There is more air resistance at a high point that a low point.
- The temperature, the ball will travel slightly faster in cold weather.
If I repeated the experiment again, I would change the angle in which the ball is dropped, to see what affects it has on the size of the crater.
