reflection and refraction

• aim - investigate the reflection of light by different types of surface and the refraction of light by different substances
• 1 - use a ray box, a lens and a slit. this produces a narrow ray of light
• 2 - take a piece of A3 paper and draw a straight line down the centre using a ruler
• 3- use a protector to draw a line at right angles. this is the normal , label it N
• 4 - Place a glass block against the first line so that the normal is near the centre of the block
• 5- draw around the glass block and turn the lights off. use the ray box to direct a ray of light so it hits the block at the normal. this is the incident ray. the angle between the incidence ray and the normal is the angle of incidence
• 6- adjust ray box to change the angle of incidence. we can see a ray reflect from the surface of the block. we can also see another ray leaving the block from the opposite side. this is the transmitted ray
• 7 - mark a path of the incident ray and the reflected ray with crosses and mark the path of the transmitted ray
• 8 - switch off ray box and remove glass box, draw incident ray and reflected ray. draw in transmitted ray so it meets the position of the block . draw a line to show the both of the transmitted ray through the glass block
• 9- use a protector to measure important angles, the angle of incidence and angle of reflection. measure angle of refraction (which is the angle between the normal and bath of the transmitted ray)
• 10 - repeat experiment using a block made from different material
• you should find the the angle of incidence and reflection are the same for both material. that is because the angle of incidence and reflection do not depend on the material
• however the angle of refraction will be different with different materials.