Physics

Is the refractive index of west lake’s water different from distilled water?
 * Research Question**


 * Ideas**
 * Checking the refractive index of west lake's water at different spots of the lake (near vegetation and where there is no vegetation) and compare them.


 * Material Required**
 * 2-4 bottles for collecting water
 * laser pointer
 * diffraction grating with 200 to 500 lines per 1 mm.
 * transparent vessel (a rectangular shaped one)
 * two clips for hanging clothes
 * adhesive tape (the best will be an insulating tape)
 * scissors
 * tracing paper (or any other semi-transparent paper),
 * book (to be used as a stand for laser).

a rectangular vessel example (can be fully opened from the top)

> the opposite wall stick a diffraction grating. > location of a zero fringe and two fringes of the first row. > interference fringes. > beam goes through water than when it goes through air.
 * Procedure**
 * Cut a part of a tracing paper with scissors and stick it to one of the external walls of a vessel. To
 * Into a ready-made vessel pour water or other liquid which refractive index you want to measure.
 * Place laser in such a way to make its beam go through the liquid and mark on the screen
 * Change the height of laser to make its beam go above the liquid surface. Again mark location of
 * Distances between fringes of the first row marked on the screen should be shorter when laser