Lesson 5: RP: Reflection/ Refraction

Question 1

What is the method for investigating how the reflection and refraction of light depends on the type of material the wave passes through?

Answer 1

1.) Take A3 piece of paper/ draw straight line down centre using a ruler.
2.) Use a protractor to draw a line at right angles to the straight line, this is the normal.
3.) Place a glass block against the straight line so the normal is at the centre of the block.
4.) Draw around the glass block. Switch off room lights.
5.) Use a ray box to direct a ray of light at the point where the normal meets the block. Adjust the ray box so that you can see a reflected ray/ transmitted ray from the glass block.
6.) Mark the path of the ray of incidence, ray of reflection and transmitted ray with crosses
7.) Switch on lights/ switch off ray block and join up the crosses for each ray.
8.) Draw a line to show the pathway of the transmitted wave through the glass block.
9.) Repeat the whole experiment using a block made of a different material ie. Perspex.

Question 2

Once we have drawn all the rays and the line showing the pathway of the ray through the glass block, what are the last 2 things we must do?

Answer 2

1.) Label the rays with their scientific names.
2.) Use a protractor to measure: angle of incidence, angle of reflection and angle of refraction.

Question 3

If you change the material of the block, do the angles of incidence/ reflection change?

What DOES change?

Answer 3

• No.
• Angles of incidence and reflection don’t depend on the type of material used.
• The angle of refraction DOES change. The angle of refraction is different depending on which material the ray is passing through.