Exploring different ways of measuring distances, especially by using their own bodies, is fascinating for children.
When you're outside, have your child pick an interesting landmark (not too far away!) and count out loud how many steps your child takes to get there. Then, figure out how many adult footsteps it takes.
Ask your child: Do you think it will be the same number if you make giant steps? What if you make tiny baby steps? Invite your child to try it and see. Talk together about what you find out.
If you feel really adventurous, and you have a group of children, try measuring distances in children. First, make sure it's a warm day! Then, choose a landmark and have the children lie down head to toe until they reach it. How many children did you need? Pick some other landmarks and try it again.
Do you have any ideas about why some distances required more children and some required fewer?