Yep, straight from syllabus, therefore important =)
Here is some info straight from my notes, hope it helps:
(1) Describe and evaluate the Michelson-Morley attempt to measure the relative velocity of the Earth through the aether
- Aim was to measure the earth’s speed relative to the aether, it was believed that if earth moved through the aether, an ‘aether wind’ should be able to be detected
- An inferometer was set up to race two beams of light, one with the aether wind (parallel to its direction relative to the earth) and another across it (perpendicular to its direction relative to the earth.)
- A single light beam was emitted from a light source, which was then split into two beams by a half-silvered mirror. The light beams travel perpendicular to one another until they are directed back to a telescope receiver by regular mirrors. The interference pattern caused by the differences in velocities of the two beams could then be observed.
- Because the direction of the earth through the aether was unknown, the whole apparatus was then rotated through 90° with a shift expected in the interference pattern, which could be used to calculate the earth’s speed relative to the aether. However, as the apparatus was rotated, there appeared to be no shift in the interference pattern. They obtained a null result.
- The apparatus had sufficient sensitivity according to the aether model but the experiment continued to produce null results despite changes in the time of day and year.
(2) Discuss the role of the Michelson-Morley experiments in making determinations about competing theories
- For a theory to be tested, predictions must be made that can be experimentally tested to determine the validity of the theory
- The Michelson Morely experiment produce a null result, which seemed to indicate that the aether didn’t exist
- New theories about the aether were made to compensate for the null results obtained, but these also failed when tested
- Einstein proposed his theory of relativity, which although it could not be tested at the time, explained the null results of the Michelson Morely experiment
- Some scientists accepted Einstein’s theory because there was no evidence against it, whereas there was a lot of evidence not in favour of the aether model
- Einstein’s theory has now been tested with all evidence in its favour, and is now accepted.
You probably should do more research, but to get you started...