In this activity, students look for symmetry in letters of the alphabet.

Mirror (or reflection) symmetry divides a figure or design into halves that are mirror images. In other words, objects are the same on both sides of a line (usually in the middle). This center line or axis can be located either vertically or horizontally.

We experience symmetry every day. Butterflies are good examples of mirror symmetry in nature. In fact, most animals and plants exhibit some form of symmetry in their body shape and their markings. Mirror symmetry is found in manufactured objects, too.

### Objectives

• Demonstrate how visible light is reflected.

### Materials

• Per student:
small hand mirror
Capital letters  (write your own with thick marker on paper or print out template)
Pencil

### Key Questions

• What makes a letter or object symmetrical?
• What are examples of symmetry in nature?
• What are examples of symmetrical manufactured objects?
• How can you test for symmetry?

### What To Do

Preparation

Review the definition of symmetry and ask the class to suggest examples of symmetry in the natural and the manufactured world (for example: human faces, butterflies, a bookshelf, maybe even the school building).

Activity

1. Print out the alphabet card template or write the alphabet (capital letters) in thick marker on paper and cut the letters out.
2. Use a mirror to find the letters that have a horizontal axis of symmetry (letters that have the same shape on top as on the bottom, like E, I and O).
3. Create symmetrical words using these letters (for example, BOB). Write just the top half or bottom half of the word and ask a partner to read it, using a mirror. Can your partner solve the word without using a mirror?
4. Now search for the letters with a vertical axis of symmetry (letters that have the same shape on the left as on the right, like M, A and O).
5. Can you create words and sentences with vertically symmetrical letters? Create puzzles by using half-letters to spell out words for a partner to solve, with or without a mirror.

Hint: These words will have to be written vertically to solve with a mirror.

Solution
Horizontal symmetry can be found in the letters B, C, D, E, H, I, K, O, and X. This means that the bottom of the letters is a reflection of the top. Some horizontally symmetrical words are: CHEEK, BIKE, BOX, BOOK, HIDE, X-BOX

Vertical symmetry is found in the letters A, H, I, M, O, T, U, V, W, X and Y. This means that the right side is a reflection of the left.Some vertically symmetrical words are:

### Extensions

• Try to find symmetry in lowercase letters.
• Did some letters change from being symmetrical to non-symmetrical, or vice versa?
• Explain that rotational symmetry, seen daily by the students when they look at flowers, domes, round grates and many other objects in their surroundings. A kaleidoscope is a good example of rotational symmetry.

### Other Resources

Science World | Alphabet Symmetry Template PDF

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