Characters from Cyber Chase: Inez and Jackie

Estimate Height With Shadows

Measure the length of shadows to estimate the height of something very tall.

Before You Play

Start a discussion with your child about shadows. Ask, "What can you tell me about your shadow?" Their response might include that shadows are attached to feet, resemble body shapes and sometimes longer or shorter. This activity works best mid-morning or mid-afternoon when shadows are longer than the height of the objects casting them.


  • Tape measure
  • Ball of string
  • 2 objects about 4 feet and 2 feet tall that can be used to cast shadows outside. (A child can be the 4-foot tall object).
  • Pencil or pen
  • Scissors
  • Printable: Shadow Math (PDF)


  1. While outside, stand the 4-foot tall object and the 2-foot tall object side-by-side in direct sunlight. Ask your child, "What can you tell me about these two shadows?" (Answers could include: The taller object casts the longer shadow. One shadow looks to be about twice the length of the other shadow).
  2. Have your child measure the 4-foot and 2-foot tall objects to confirm that one is twice as tall as the other.
  3. Now, have your child cut 2 pieces of string to the lengths of the shadows cast by these objects. Use these string lengths to demonstrate that one is twice as long as the other. Ask, "What can you tell me about the relationship between the two shadows and the two heights?” (Answers could include: They are each twice as tall or twice as long as the other. The objects and their shadows share the same relationship.)
  4. Take your child to the tall object you’ve selected. Ask, "How could we measure the height of this?" Then ask, "How can we use what we just learned about objects and their shadows to estimate the height of this object?"
  5. Give your child a copy of the printable, pencil, tape measure, string and scissors. Review the printable together. Explain that they should measure shadow lengths in as straight of line as possible to keep measurements accurate.
  6. Allow time for your child to do the activity, then discuss the results.

This activity comes to you from the creators of Cyberchase.

Iowa PBS STEAM Activities and Crafts provided by PBS KIDS Parents.