It is hard to get the bars to be parallel in this experiment. explain why the bars tend to be so wiggly that happens because there is not match friction between the glass plates and it makes it hard to move them gradually relatively to each other, plus the surfaces of the glass plates are not entirely even which makes the friction vary in different areas of the glass plates and their movement even less predictable 2. explain why it is necessary to use a special sodium vapor lamp for this experiment rather than an ordinary white lamp ordinary white light is not monochromatic therefore it is not suitable for this experiment (the pattern of interference wouldn't be clear with non monochromatic ight). sodium vapor lamp serves us as a source of monochromatic light 3. explain how the number of bars to be counted would be affected if the lamp were changed to a different source producing red light. would this make the uncertainty in the experiment smaller or greater? each color corresponds to a different wavelength. while the thickness of the film at a certain location may not allow red light to emerge from the film in phase, it may be just perfect to allow yellow light wave to emerge in phase. thus yellow light wave goes through constructive interference and becomes brighter than the other colors. using the a red light source would make the readings harder and increase the uncertainty 4. explain why it is better to place the hair as far as possible from the contact point of the glass plates. because we want the plates as close to being parallel as possible, in the first at of ourderivation we 4. explain why it is better to place the hair as far as possible from the contact point of the glass plates. because we want the plates as close to being parallel as possible, in the first part of our derivation we assume that the plates are parallel and to minimize the error we should make them as parallel as possible. 5. how would dust and oil on the glass plates affect the results? the presence of dust and oil makes the result of the experiment less accurate. dust and oil absorb reflect and refract light rays changing the destructive/constructive interference pattern and making the readings less accurate. 6. what percentage error would result from miscounting the bars by one? difference in experimental and actual value % error=- actual value the difference in experimental and actual value is 1, if we let actual value to be n, then 100 %error== % 7. how would the data and results of the experiment be affected if instead of glass we had used a different transparent material for the plates?