Here's a fun way to sneak in some work in math that covers measuring, counting and shape recognition.
Background: A tessellation is tiling a flat surface with shapes so that there are no gaps or overlaps. This activity uses equilateral triangles and rhombuses (diamonds) to create designs that tessellate.
Print the triangle and rhombus nets from http://www.familymathnight.com/pdf/saltdoughtessellations.pdf. Glue onto cardboard, cut out and tape together. Be sure to tape the edges as this will help prevent the cardboard from getting moist.
Make the salt dough:
2 cups all-purpose flour
1 cup fine salt
¾ -1 cup water
Have your child help you measure out the flour and salt into a bowl. Add ¾ cup of water and mix. Mixing with hands is messy but a lot of fun. Add water as needed until dough is firm but still workable.
The math: Which is more, one cup of salt or two cups of flour? How many more cups of flour did we put in compared to the salt? If we doubled the recipe, how many cups of flour would we need? How many total cups of ingredients did we add to the bowl?
Roll out the dough to a thickness of about ¼ inch.
The math: Can you use this ruler to help me find ¼ of an inch. Do you think it's going to be more than on inch or less than one inch? Advanced: How many ¼ inches are in one inch?
3. Use the cookie cutter triangle and rhombus to make shapes.
The math: How many triangles did you make? How many rhombuses (also called parallelograms) did you make ? How many total shapes did you make? Which shape did you make more of? How many more/less does the triangle have than the rhombus? How do you know this is a triangle? What can you tell me about the lengths of the sides of this triangle (they are all the same)? A triangle with all sides the same length is called an equilateral triangle. What can you tell me about the rhombus?
4. Bake shapes at 200 degrees for 20 – 30 minutes. (An option is to let them air dry which takes about 2 days. Turn over periodically to allow for even drying.)
The math: Can you help me find 200 on the oven (or however your oven works so that there is an opportunity to discuss '200'.) Advanced: If we put them in for 20 minutes and we have 15 minutes to go, how much time have they been in the oven?
Paint the shapes, including the sides, and let dry.
Use the shapes to make designs that tessellate. Note: The shapes may not fit together perfectly. That's okay and part of the charm of the activity. When the designs are made and without picking up the pieces, glue the edges together using white glue or a hot glue gun. Colored glue can be made by adding food coloring to white glue or using colored glue for the hot glue gun.
Left-over shapes can be used as refrigerator magnets!