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In this exploration, children build sandcastles to experience how water and sand interact with each other. Water clings to grains of sand to "glue" them together and make a great building material!

Wet and Dry printable guide.

This activity was developed and tested with preschool and kindergarten educators as part of Science World's Big Science For Little Hands program. 


  • Build structures out of sand.

  • Compare and evaluate using dry versus wet sand.


  • Per Class or Group:
    a tarp for the floor, or suitable outdoor space
    small buckets and containers, e.g. yogurt containers
    small shovels
    spray bottles

Key Questions

  • Does dry or wet sand make a better sandcastle?

What To Do

  1. On a tarp or outside, have children fill buckets with dry sand and turn them over to try to make sandcastles.
  2. Show them how to spray the sand and make it damp before trying another sandcastle.


  • Leave sandcastles made from wet sand in the sun to dry. What happens to the sand when the water evaporates?
  • Spray walls or windows with water and see if you can "glue" paper to the wet surface.