Secret Messages with Mirrors
Guest post written by Sarah from Share it! Science. Sarah is a science educator with over 10 years of experience sharing science in nature and environmental centers, museums and schools. Follow Share it! Science on Facebook, Twitter, Pinterest and Google+!
This exploration of symmetry and mirrors is always a big hit whenever I try it with the kids. The set-up is simple and you only need a few supplies.
- A small mirror (plastic ones are best for small hands)
- Markers or other art supplies
- Index cards or scrap paper
- Ball of modeling clay or a can (optional)
First, explore how a mirror’s reflection can change an image. Kids can write letters, words, pictures or just scribbles and hold the mirror upright on top of their pictures. As they move the mirror around, what do they see?
We use either a ball of modeling clay to make a stand for the mirror, or attach a small can (tomato paste works great!) to the back of the mirror to help hold it up while we’re investigating.
Through this investigation kids will probably discover that mirror images are reversed in the direction perpendicular to the mirror’s surface. In other words, they appear reversed left or right. If the mirror is placed directly in the middle of a symmetrical image, you can reproduce the entire image, half on paper, half as a reflection.
A fun activity to try with this new knowledge is to make secret messages. Several letters of the alphabet are symmetrical. By drawing only half of the symmetrical letters you can create a secret code that can only be cracked by setting a mirror down next to the partial letters. Letters that are not symmetrical can be replaced by shapes that are symmetrical.
By creating a key and a paper with the “secret code” kids can create messages and trade them back and forth to solve.
Another fun activity is to draw a scribble or shape and move the mirror around to see how many different images can be made from it. Sometimes a hidden picture emerges. Kids can also draw half an image and have their friend guess what the picture is before solving the puzzle by using the mirror to see the entire picture.
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