Build and test a cardboard boat
Why do some things float and others don’t? Learn about a predictor for buoyancy, and how to size and build a boat out of cardboard. Want to have some fun? Build a surfboat! Or, build something smaller that you can test in your bathtub. Your creativity is the limit!
cardboard boat Project!
It all began with a real cardboard boat race…
Then the threat of “Battle Boats” prompted a unique design concept… CARDBOARD TUBE TRUSSES! And the unsinkable surfboat was born!
This makes a fantastic team or family project! Adult supervision / help needed for cutting the cardboard.
Printables included so you can award medals and participation badges! Just add ribbon!
Buoyancy - submarine simulation
How does a huge cruise ship stay afloat? Yet a penny sinks?
Your mission, should you choose to accept it, is to discover a predictor for whether something will sink or float.
- Is it weight?
- Is it size?
- Is it density?
We’re going to try and test each of these hypotheses. Your job is to figure out a simple experiment to try and disprove each one, until we get to the one that works!
Along the way, we’ll try to simulate a submarine… the ultimate machine that can control when it sinks and when it floats. If we can unlock those secrets, we can design a boat that will float!
Think like an engineer / buoyancy experiment
This experiment complements the buoyancy / build a cardboard boat project from my second book, The Buoyancy Project: Putney Hicks Inventor Adventures – Book 2.
The videos immediately below give an introduction to a simple problem-solving process. We have 3 hypotheses or “guesses” about a predictor for why some things float and others don’t, then conduct simple experiments to test each hypothesis in turn.
Once we can predict whether something will sink or float, we can use that knowledge – in the form of a simple math recipe – to design or size a boat. That’s the next challenge!
I did these experiments for middle grade kids at Blanchester Intermediate on March 4, 2021. It was so amazing, that I duplicated the experiment at home and shot video. You can grab all my videos and experiments with the Buoyancy – Submarine Simulation and Cardboard Boat Experiments!
The Buoyancy Project
Want to check out the book that expands on the project & adventure? Check out the Buoyancy Project: Putney Hicks Inventor Adventures–Book 2!
- 2023 Firebird Book Award – WINNER
- 2023 Global Book Awards – Gold Medal WINNER
- 2023 BookFest Book Awards – Silver Medal WINNER
- 2023 Gertrude Warner Middle Grade Awards – Semi-Finalist
- 2023 Maincrest Media Book Award – WINNER!
- 2023 Royal Dragonfly – FIRST PLACE
A perplexing task. A mystery to solve. Can a scientist-in-the-making find the answers hiding in plain sight?
Putney Hicks is itching to take on her next challenge. Preparing for her school’s cardboard-boat regatta, the twelve-year-old inventor hunts down ways to stop the flimsy craft from sinking into a soggy mess. But after she rescues her neighbor’s dog from a rip current, the curious girl can’t shake the thought that the solution is right in front of her eyes…
Joined by her new canine companion and using her magical tablet as she explores an alligator-infested lagoon, Putney is dismayed when she’s paired on the project with her arch-nemesis. And as they reluctantly put their heads together, she suddenly realizes that the scaly swamp predators could hold the secret to their experiment’s success.
Can these stubborn rivals overcome their differences and construct a winning waterproof design?
The Buoyancy Project is the ingenious second book in the Putney Hicks Inventor Adventures middle-grade series. If you like scientifically empowered young women, entertaining escapades, and real-life mathematical motivation, then you’ll love Marsha Tuft’s MacGyver-like enterprise.
Buy The Buoyancy Project to sail full STEM ahead today!
What's the fun all about?
Here’s a short video showing a simple cardboard truss raft and a similar (slightly refined) surfboat with foam insulation platform covered in marine grade fabric shell… for easy carrying to the beach, or a pool on raft night!
My great-nephews had a blast!
Teaser video - 3:35
Making cardboard tube trusses - 14:31
stand test - cardboard trusses - 0:37
build and test a cardboard boat
Why do some things float and others don’t? Learn about a predictor for buoyancy, and how to size and build a boat out of cardboard. Want to have some fun? Build a surfboat! Or, build something smaller that you can test in your bathtub. Your creativity is the limit!
Materials needed:
- Cardboard… how much depends on how big you want to build your boat, and what you want it to be able to hold.
- A measuring tape
- A calculator (or access to a computer… sample spreadsheet provided)
- Duct tape
- A plastic tablecloth (or 2 or 3, depending on how large you go with your boat)
- Something to cut your cardboard with
- Someplace to test your boat… like a bathtub, pool, or lake.
- OPTIONAL: some weight, to verify that your design works. Which means, you’ll also need to be able to weigh your boat with the extra weight. (You can always do this by standing on a scale holding your boat and the weight, then subtracting the weight of you alone.)
Experiment video - 32:00
All photos by MK Tufft with the exception of the following two images from the “Why do some things Float? Others Don’t?” poster (above):
- Cruise ship image by Limbovision from Pixabay
- Submarine image from https://www.navy.mil/management/photodb/photos/030814-N-0000X-003.jpg . ”The appearance of U.S. Department of Defense (DoD) visual information does not imply or constitute DoD endorsement.”
More pics
