i believe u juz need to able to describe wat they did, wat they tried to find, and wat was the outcome.
according to the NSW hsc online website:
perform an investigation and gather first-hand or secondary data to model the Michelson-Morley experiment
Perform the investigation that may be planned by your teacher, by carrying out the procedures efficiently and safely.
Any model of the Michelson-Morley experiment will need to compare the speeds of two identical moving objects by racing them. One of the objects is to move back and forth along a current or wind, and the other is to move back and forth across the current or wind. Suitable objects might be model sailing boats or cars, or perhaps model motorboats racing on a creek. When a comparison of this sort is done properly, the gathered data should show that the object that moves across the current always wins the race.
Michelson and Morley performed a similar comparison between two light rays. They were trying to detect the presence of an aether wind that should exist according to the aether model. However, they found that the light rays always finished their race together, with no clear winner, so that they had failed to find the aether wind. This is described as a null result.
The Michelson-Morley experiment , a web page of the Department of Physics, University of Virginia, that describes the Michelson-Morley experiment in some detail.
describe and evaluate the Michelson-Morley attempt to measure the relative velocity of the Earth through the aether
The Michelson-Morley experiment was devised to detect the aether using light and an effect called interference.
As the Earth was supposed to be moving through a stationary aether, there should have been an apparent aether wind. The speed of light was supposed to be constant in the aether, so this aether wind should slow down light heading into it, as seen by us. The Michelson-Morley experiment compared the speed of such a light ray with another light ray directed across the aether wind. The two rays were compared using an interferometer, a device that displays interference effects. No significant difference was found between the two light rays.
The experiment was of sufficient sensitivity according to the aether model, yet failed to detect any presence of the aether. No matter who did the experiment, where it was done or when it was done, no one was able to physically demonstrate the interference effect that would prove the existance of the aether.
discuss the role of the Michelson-Morley experiments in making determinations about competing theories
From theory come predictions that can be tested. Experiments are performed to test the predictions, and from the results of the experiments, judgements can be made regarding the validity of the theory. The Michelson-Morley experiments were performed to test the prediction, based on the aether model, that an aether wind should exist.
The Michelson-Morley experiments were performed in 1887 and had null results, despite satisfying all requirements regarding sensitivity. This did not, however, disprove the theory.
Various modifications of the aether theory were offered over the following years. Each modified theory resulted in new predictions to be tested. Each test failed.
Almost twenty years after the Michelson-Morley experiments, Einstein proposed the theory of relativity, in which the aether model was not needed. The theory of relativity produced its own set of predictions, not all of which were testable at that time. As technology has improved, the predictions have been tested and found to be correct.
The choice for scientists was as follows: continue to follow a theory for which no predictions proved true (aether) OR follow an alternative theory for which prediction do prove true (relativity).
or for furthur info:
http://galileo.phys.virginia.edu/classes/109N/lectures/michelson.html
