Preschool science project: Floating and boating

© 2009 Gwen Dewar, Ph.D., all rights reserved

These activities allow kids to explore the concept of buoyancy. The first preschool project is that old standby — “floaters and sinkers.” The two that follow introduce children to the more complex activity of boat-building.

To help kids develop a deeper understanding on the subject, tackle these activities in the order given. And let kids take their time. The activities can extend over a period of many days.

Preschool science project #1: Floaters and sinkers

Give kids a bowl of water and a variety of objects to test. What sinks? What floats? Supervise kids so they don’t put the objects in their mouths, and beware of choking hazards for kids under 3 years (e.g., aluminum foil, buttons, coins, stones, etc.).

Here are some suggested objects to try:

  • Aluminum foil (for older kids only)
  • Bark
  • Coconut flakes
  • Crayons
  • Keys
  • Leaves
  • Pine needles
  • Plastic bottles (empty and capped; also full of water and capped)
  • Plastic cards
  • Plastic dishes
  • Plastic toys
  • Rice grains
  • Sand
  • Soap bars
  • Stones and rocks (too large to be swallowed)
  • Sunflower seeds

Preschool science project #2: How does shape influence whether or not an object can float?

Let kids test the effects of shape on an objects “floatability.”


  • Clay (for younger kids) and/or aluminum foil (for older kids)
  • A large container of water


Create a variety of shapes from clay or aluminum foil. Make sure you make at least one ball (of clay or of wadded up foil). Try creating other shapes that are “boat shaped.” Then test your shapes in a bowl or tub of water. What happens to the balls? Can you create shapes that float?

Preschool science project #3: Making boats

In this open-ended preschool science project, kids create their own boats from recycled materials and test their boats in the water.

Suggested materials

  • Water-proof tape
  • Rubber bands
  • Pipe cleaners
  • Glue
  • Miscellaneous recycled materials, including milk cartons, egg cartons, pie tins, plastic cups, plastic drinking straws, Styrofoam containers, corks, popsicle sticks, string, plastic bottles, modeling clay, etc.


Before attempting this stage of the preschool science project, kids should have experience with floating and sinking (stages 1 and 2). Kids might also benefit from free play with ready-made toy boats in a tub of water.

In addition, read together about different kids of water craft. Check out these titles for preschoolers:

Busy Boats (Amazing Machines) by Tony Mitton and Ant Parker, and Boats (Picture Puffin Books) by Anna Rockwell.


Avoid telling kids how to build a boat. Let kids create their own designs-—however goofy! If you want, you can guide by example. Participate as a peer, quietly making your own simple boat.

When the boats are finished, try floating them in a tub or wading pool. Watch what happens and encourage kids to analyze why some models work better than others. Can kids use what they learned to design their next boat?

More ideas For tips on choosing an preschool science project for your child, see this article on preschool science activities.