At Home Activity: Sink or Float

An image of water with two red arrows, one pointing up, one pointing down.

Sink... or float? 

And no, we’re not talking about how we feel right now—we're talking about today’s at home activity for your kids, which happens to be all about trial and error.  

It’s a good way to encourage kids to experiment, test, adjust, and test again.  

Perseverance is more important now than ever—and activities like this one let you practice it with your little ones.  

Sink or Float 

Goals

  • Explore how surface area helps something float 

  • Test, fix, and retest 

Children will: 

  • Create a boat out of aluminum foil  

  • Test how much their boat can carry 

  • Redesign their boat based on their test 

What you’ll need: 

  • Large flat-bottomed container that will hold water 

  • Water 

  • Aluminum foil  

  • A quantity of something heavy like marbles, washers, or pennies 

How to: 

  • Fill the container with water. If you don’t have a container large enough the bathtub or sink work too!  

  • Cut a piece of aluminum foil to roughly 6 by 10 inches and shape it into a boat. When constructing your boat ask yourself: What does a boat look like? What makes a boat float? 

  • Place your boat in the tub of water and make sure it floats 

  • Now add your cargo one by one, and take a guess how many your boat can hold: How many pennies do you think the boat will carry without sinking? Let’s see! 

  • Try making your boat a different way. Does it hold more or less cargo?