Ship Shape Math Fun

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Ship Shape Math Fun

July 23, 2014

Ahoy, mateys! My buccaneers love to play with water and the recent Float Your Boat printable got us thinking more about water crafts. Is there a reason we don’t see round or triangular pirate ships? We are going to explore this, so grab your pirate hat and let’s get started.


The Math Behind Buoyancy

When you drop a penny into a cup of water it sinks. So how does a boat made from copper-coated zinc not sink? The tendency of an object to float in water is called buoyancy.  Buoyancy is also defined as the power of a fluid (we usually think of water) to exert an upward force on something that is placed in that fluid. Shape is an important factor that affects buoyancy. Density, an object’s mass in relation to its volume, is also significant. You can read more about this at Science Buddies.

Little pirates don’t need a shipyard to learn more about buoyancy; they can experiment right in the bathtub. Or in the backyard. But we don’t recommend trying this in a bathtub in your backyard!

Shape Your Own Boat

Building your own pirate ships and testing them will require the following items:

  • aluminum foil
  • scissors
  • ruler
  • container with water (kiddie pool, sink, or bathtub)
  • pennies, marbles, or other items for cargo
  • paper towels

Give each of your buccaneers their own 12-inch square of aluminum foil. Design a boat with a large surface area and sides that will allow you to add as much cargo as possible. Set the ships into water and make sure they float and there are no leaks. Now load your cargo onto the boat, slowly and carefully, one item at a time.

Can your crew predict how many items the will be able to hold before it sink?

Add more weight to the ship until it’s time to send an SOS distress signal because the vessel is sinking or leaking. Count up the items and keep track. If you want to be more accurate, dry them off and weigh them. After all, pirates do like to keep track of their prized possessions.

Keep trying different shapes and sizes of the foil. We made square, rectangular, triangular, and circular ships. Older kids will notice how the surface area of the boat makes a difference in the ability to haul more weight.

If your family of pirates wants to continue to test ships, try making ships that are the same shape, but made of different materials like duct tape. Pirates also set sail in salty seas. Add salt to your water and note how that affects your ship’s capabilities.

Argh, we just found a bit of buried treasure! Set sail for math success with this archived Bedtime Math problem.

Photo courtesy of Beth Levine

Print Friendly, PDF & Email

About the Author

Beth Levine

Beth is a mom of two young boys in the Capital Region area of New York. She blogs at and can be found on Twitter via @TheAngelForever. Beth is a lifelong learner and educator that is always looking for new and fun ways to get kids thinking.

More posts from this author