Question 11
Think like a scientist: Measuring angles of incidence and reflection
In this investigation, you will investigate the law of reflection.
Work in pairs or groups of three.
Make the room as dark as possible for this activity.
You will need:
• equipment shown in the diagram
Method
1 Set up the equipment as shown in the diagram.
2 Place the plane mirror vertically at one side of the white paper. Mark the position of the front of the mirror on the paper using a pencil.
3 Use the protractor to draw a normal line at the surface of the mirror.
4 Use the ray box to direct a ray of light onto the mirror where the normal meets the mirror surface.
5 Use a pencil to make marks on the paper for the positions of the incident and reflected rays, as shown in the diagram.
6 Turn the ray box off, remove the mirror and use the pencil marks to construct a ray diagram.
7 Measure and record the angle of incidence, i and the angle of reflection, r from your diagram.
8 Repeat this for at least four more different angles of incidence. Use a new piece of paper or a new area on the same piece of paper each time.
Record your results in a table with two columns: angle of incidence and angle of reflection. Remember to include the unit.
In this investigation, you will investigate the law of reflection.
Work in pairs or groups of three.
Make the room as dark as possible for this activity.
You will need:
• equipment shown in the diagram
Method
1 Set up the equipment as shown in the diagram.
2 Place the plane mirror vertically at one side of the white paper. Mark the position of the front of the mirror on the paper using a pencil.
3 Use the protractor to draw a normal line at the surface of the mirror.
4 Use the ray box to direct a ray of light onto the mirror where the normal meets the mirror surface.
5 Use a pencil to make marks on the paper for the positions of the incident and reflected rays, as shown in the diagram.
6 Turn the ray box off, remove the mirror and use the pencil marks to construct a ray diagram.
7 Measure and record the angle of incidence, i and the angle of reflection, r from your diagram.
8 Repeat this for at least four more different angles of incidence. Use a new piece of paper or a new area on the same piece of paper each time.
Record your results in a table with two columns: angle of incidence and angle of reflection. Remember to include the unit.
