CRATER EXPERIMENT

Strategy

Aim: The aim of this experiment is to discover the relationship between the height of the marble being dropped and the diameter of the crater produced.

The input variable (what I will measure) is the height that the marble is being dropped from. The output variable (what I will measure) will be the size of the crater produced.

The science behind this experiment is quite simple. The higher you drop the marble the bigger the diameter of the crater will be. Gravity and drag forces are involved in the dropping of the marble, and then as it hits the sand, a small amount of kinetic energy is created. The higher I drop the marble the more gravitational force and the more kinetic energy, therefore increasing the diameter of the crater. There is also drag in this experiment which could limit the speed of the marble being dropped, therefore decreasing the diameter of the crater.

Change in Gravitational Potential Energy = Mass x Gravity x Change in Height

Kinetic energy = ½ x Mass x Velocity2

Equipment

Marble – I decided to use a small marble for my experiment as it is very convenient. I have chosen to use a marble because it is perfectly rounded without any jagged edges, which will make the almost perfect semi-sphere for a crater. This will make my results all the more reliable and accurate.

Meter Ruler

As you can see I have averaged out every two measurements to make my results very accurate. From this table of results, it is quite simple to spot a trend. As you increase the height of the marble being dropped from, the diameter of the crater increases too. Any outliers are highlighted in red; this helps me distinguish accurate results to inaccurate results. By this I can decide not to use these outliers for my averages and my graphs, but as they are not that major and wouldn’t make much a difference to the trend that is being spotted.

I also took my measurements in millimetres, which is an accurate scale to use in this type of experiment, however this could be improved by using tenths of millimetres or an even smaller scale.

The flattening of the disturbed sand was probably the most inaccurate part of the experiment, and could be improved. After I had dropped the marble and took my results, I had to shake the tin, until the sand was flat (in my eye). However I cannot be 100% sure that it was flat, and this is why it was the most inaccurate and unreliable part of the experiment. If I were to repeat the experiment I would use a machine or a flat surfaced object to smear the surface of the sand until it is flat.

I have thought about these precautions greatly and have decided that certain aspects of the experiment could have been improved. However, on the whole, I believe that I done everything to a precise degree of accuracy and to my best ability. This effort has given me a very accurate conclusion and reliable graphs and results, which corresponded greatly to my hypothesis and the science behind the experiment.

Jake Jeal