Secret Message Shapes

Make two mystery objects in advance. Tip: For the printable, use heavier paper if available.

Ask, "What’s the difference between 2-dimensional and 3-dimensional objects? Where else do we see 2-dimensional shapes being used to make 3-dimensional objects? (Examples include blueprints for structures, schematics for assembling household items, and some gift and storage boxes.)

Tell your child that she is going to make her own 3-dimensional object out of a 2-dimensional shape and use it to send a secret message! Show her the two irregular pyramids (mystery objects) you made ahead of time. Demonstrate different ways they can fit together, face to face. Say that you’ve figured out a way to write a secret message that can be read only when three or four of the objects are put together just right. But first, she has to make her own!

Have your child look at her “Mystery Object” printable. Ask, "What 2-dimensional shapes do you see? (Triangles, square.) What do you think the 3-dimensional object will look like?"

Have her cut out and begin assembling her pyramid. Help with the cutting and folding as needed. After the object is made, Ask, "Does your object look the way you thought it would?"

Consider giving your child a challenge. Say, "You can put three of these irregular pyramids together to make a cube or four together to make a regular pyramid. Or you can make something else by putting them face to face. Once you have made something new with three or four of these, I’ll show you how to write your secret message."

After a few minutes, demonstrate how to write with markers across the objects so the message can be read only when all the pieces are put together. When she’s written her message, your child should swap the disassembled objects with you to see if you can reassemble them and read her secret message!