Aim
Investigate the reflection of light by different types of surfaces and the refraction of light by different substances.
Equipment List
- Ray box Suitable power supply
- Collimating slit and lens
- Several transparent blocks made from different materials - glass, perspex, plastic.
- 30cm ruler
- Protractor
- Sheets of plain A3 paper
Method
- Slot the collimating slit into the ray box and turn on, producing a narrow ray of light.
- Place the first block of material on top of a piece of paper. Trace around the block using a pencil.
- Draw a normal to the block (a line at 90° to the surface of the block). Align the incident ray of light with the meeting point between the normal and the surface of the block.
- Draw the reflected ray and refracted ray, as shown in the diagram below. Remove the block and draw a straight line between the point of reflection and the refracted ray on the other side of the block.
- Using the protractor, measure:
- The angle of incidence - The angle between the incident ray and the normal.
- The angle of reflection - The angle between the reflected ray and the normal.
- The angle of refraction - The angle within the material between the normal and the refracted ray.
- Repeat the experiment, using a new piece of paper for each different material of block.
Safety Precautions
- Be careful of dropping materials like glass that could shatter
- Room has to be darkened so be careful of surroundings
- Ray box could heat up