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Mirror, Mirror

We’re all used to seeing ourselves in the mirror many times each day, but are we seeing ourselves exactly as we are?”

What is a mirror image, anyway? This game introduces the idea of mirror images through fun, physical action. 

Mirrors and Light

Light is a type of energy that we can see, and mirrors are a great way to teach the properties of light. When light meets the surface of an object, three things can happen. The light can be bounced (reflected), bent (refracted), or absorbed.

Reflection

When light from an object hits a flat, shiny surface, nearly all of it bounces off (is reflected) in a predictable way. The light bounces back at the same angle it came in at. When your eye catches the light, it appears as though it came from behind the mirror. 

However, this is not really the best way to describe the reflection of a light ray. Light rays have a wave nature. Waves are often described as “turning back” rather than “bouncing” when they reflect.

When you look in a flat mirror, you see a reflection of yourself that is the same size as you but reversed.

Right and left are reversed in the image because a light ray coming off your right hand bounces off the mirror, and into your eye. To your eye and brain, the light ray appears to have come from the left hand of someone who looks just like you, standing on the other side of the mirror. Because the image is “behind” the mirror, your right hand is their left one. 

We may describe a reflected image as “switched from side to side”. But really, a mirror only changes the direction the object is facing into and out of the mirror. That is, back to front or front to back . 

Objectives

  • Explain properties of visible light.

  • Describe how light rays can change direction.

  • Demonstrate how visible light is reflected.

Materials

  • Per Class or Group:
    classroom or outdoor play area
    whistle (or equivalent noisemaker)

Key Questions

  • What was the same about you and your “mirror image”?
  • What was different about your movements? For example, when you moved your right hand, which hand did your “mirror image” move?
  • On what side does your hair part? What side does your mirror image’s hair part?
  • How would you describe the image you see in the mirror? Backwards? Reversed? Opposite?

What To Do

  1. Ask students how many times a day they look in a mirror. What is special about the image they see (their reflection)? Discuss what they already know about reflected images.
  2. Pair students up and ask them to face each other.
  3. Each pair chooses one student to be the main image and one to be the reflection.
  4. The reflection has to copy everything the main image does (as if they were a reflection in a mirror).
  5. Encourage the main images to make funny faces, turn to the side or all the way around, jump up and down, and so on.
  6. After a minute or so, ask students to swap roles.
  7. Repeat steps 5 and 6 for another minute.
  8. (Optional) Choose the strongest pair of “main image and reflection” to perform for the class.