Mirrors
You are in the middle of two mirrors set at an angle of 50°. Your eyes are 1 meter from the vertex and you can see 6 images of yourself. The problem is to determine how far away from you each of those images are. This is a curious problem, but it is rich and engaging. And there’s a wonderful surprise at the end.
A number of students will have trouble understanding what the problem asks. “Aren’t the images simply on the mirror? But once they look in the mirror, they will see that some of the images of their face are much smaller than others. And what we are after is that “apparent distance”.
So you ask them how the image gets to your eye. Look in the mirror at your nose? How can you see your nose; how does that information travel? Somehow there must be a ray of light that travels from your nose to your eye. How can that happen? And wouldn’t the distance of the image be the length of that light ray?
