An experiment with a torch
Part 1.

For this experiment you need a rectangular pocket mirror, a torch, a peg and a slice of thick paper which has a crack (1-2mm) towards the end of the slice. This slice should be twice the length of the mirror but shorter as twice the height of the mirror. (Example: If the mirror is 7cm long and 10cm high the slice of paper should be 14cm long but must be shorter than 20cm. A length of 17-18cm would be perfect.)
Shade the room in which you are conducting this experiment.

Set up the experiment as shown in the picture above. The mirror is set vertically. The slice of paper should be parallel towards the mirror. Try to focus the light of the torch through the crack in order to hit the right edge of the mirror. There the light should be reflected and hit the right edge of the paper (see image above). Maybe you might have to arrange the paper a little bit towards the left or right in order to succeed.

The slice of paper remains at this place. Rearrange the torch so that the light hits the crack and the left edge of the mirror. There the light should be reflected and hit the paper. Mark the spot where the light hits the paper with a pen. The distance between the right edge of the paper and the mark on the paper show the size of the paper that the mirror can picture in this position. Measure the size of this distance.
Compare the size of the mirror and the size of the distance on your paper. What can you say about that?

The distance on the paper is exactly...

...the size of the mirror!
...twice the size of the mirror!
...half the size of the mirror!