Your Reflection Moves with You

You smile at a mirror, and the face in front of you smiles too. You wiggle your nose, and that nose wiggles right along with yours. Why does the face in a mirror move when you move?

The answer starts with light, the brightness that lets you see things. During the day, the sun can send light through a window. A lamp can give you light too, so you can see even after sunset.

Some of that light reaches your face and bounces off it. Light bounces off your cheeks, your nose, and your chin in many directions. When you face a mirror, some of the light from your face travels toward it.

A mirror is smooth and shiny. Because it is smooth, it bounces light back neatly. That helps your eyes see a clear picture of your face.

Some of the light bounces from the mirror into your eyes, letting you see a reflection. A reflection is the picture you see in a mirror. Your reflection shows your own face because that light came from your face.

Here comes a little guessing moment. If you open your mouth wide in front of the mirror, what will your reflection do? Think about the light bouncing from your face.

Your reflection shows an open mouth too! When you move your mouth, light bounces off your face in a new way. The mirror bounces that light toward your eyes, so you see your mouth move.

The mirror does not keep an old picture of you. Light keeps reaching your face and bouncing toward the mirror as you move. That means your reflection shows your smile now, then your puffed cheeks, then your smile again.

Light comes back to your eyes so quickly that your reflection seems to move with you. There is no other person in the mirror. It is a picture that changes as your face moves.

Here is the path: light, your face, the mirror, your eyes, your reflection. The face in a mirror moves when you move because light bounces from your moving face to the mirror and back to your eyes.

The next time you share a quiet smile with your reflection, you will know how light brings that smile back to you.