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1. Arrange two small mirrors so that they form a straight line (1). The angle between these mirrors is 180º.

2. Place a colourful object (such as a light stick or a golf tee) in front of the two mirrors. You will see one image of the object.

3. Change the angle between the mirrors to 120º (2). How many images do you see now?

4. Change the angle to 90º (3). Count the images.

5. Try an angle of 60º (4). Count the images.

6. Gradually, make the angle between the mirrors smaller and smaller. What happens to the number of images?

7. Arrange two mirrors so that they face each other, as they would if they were on opposite sides of a room. Place a colourful object between these two mirrors. Look over the top edge of one of the mirrors and try to count how many images you see.

Challenges

Can you figure out a rule that permits you to predict the number of images you will see in a pair of hinged mirrors, for any of the angles in the diagrams above? Hint: There are 360º in a circle.

Will your rule work for these angles? 45º,40º,30º,20º,10º

Try it!

Extra! Make a ‘mirror box’, and place a small flashlight or light stick inside it. (You will need at least 5 small mirrors.) Can you count the images you see when you look over the top edge of one side