Build a Popsicle Stick Paddle Boat
Dive into the world of 3-D printing with this activity from 4-H’s 2020 STEM Youth in Action winner.
About the Activity
This fun STEM activity comes from Joseph Huff, the 2020 STEM Youth in Action winner. Kids will build a self-propelling boat while learning the basic skills needed for 3-D modeling and printing – and they’ll also learn about water resistance, thrust, and the transfer of energy.
Topic: STEM, Physics
Estimated Time: 90 Minutes
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These simple materials will get you started.
- Popsicle sticks
- Rubber bands
- Hot glue gun
- Optional: Things to decorate your boat with, like stickers or glitter or googly eyes (why not?)
Follow these steps to build your own, self-propelling popsicle-stick boat.
- Lay two popsicle sticks on the table; break or cut another popsicle stick in half, and sand down the rough ends where they have been cut.
- Lay down the cut pieces in between the two uncut sticks so that they stick out in front of the two uncut sticks. This creates an opening in the center of what will be your boat. Push the uncut and cut sticks together so they are side by side, other than the gap behind the uncut sticks. Did You Know? A pointed shape in front helps the boat cut through the water, minimizing the drag, or resistance, the water gives to the boat.
- Measure and cut strips out of another popsicle stick that can lay across the width of your boat.
- Next, lay a strip of glue across the sticks, ahead of the opening.
- Place a cut strip across that line of glue.
- Repeat this, laying down more strips of glue and placing your measured and cut width-strips across the boat until you reach the part that sticks out in front.
- Repeat this in the rear, putting down dots of hot glue on the two strips in the back of the boat, and laying down strips across the width of the boat. Be sure to leave an open space in the middle, about four inches long.
- Next, repeating steps 1 and 2, lay out and glue down another set of sticks that run the length of the boat on the outside, and make a pointed bow in the front.
- Next, cut two small strips to run in between the two sides in the rear, or the stern, of the boat.
Did You Know? Your boat now has three layers of popsicle sticks, giving it structural stability that will be vital for the propulsion that the rubber band will apply to it.
Also: 3-D printing is all about layers – physical objects are made from a 3-D digital model using a machine that lays down many successive layers of a material to create the designed product.
- Cut a popsicle stick into two pieces that are slightly smaller than the length of the gap in the middle of the boat.Fun Fact: The larger you make the paddle wheel blades, the faster the boat will go. It’s all about water resistance and water displacement – a bigger blade can displace more water, pushing your boat faster. Of course, here you’re limited by the size of your boat’s opening, so if you want a bigger wheel, you need to make a bigger boat with a bigger opening!
- Stack the cut sticks on top of each other, then place them on their sides.
- Hold them tightly together on their sides, still pinching them together (if you have a workbench vice, use that).
- Use a saw or file (a pocket knife saw is ideal) to cut a groove into the two stacked popsicle sticks. Be sure you’re cutting from the sides until you cut halfway through the two sticks.
- Now, sand down the two rough ends from where they were cut; try to make them look like the rounded ends of the popsicle sticks.
- Interlock the two sets of paddle wheel blades.Note: This creates a smoothly interlocking wheel. But if you don’t want to saw, you can make your paddle by cutting one stick to about three inches long, then cut two smaller strips half that length, and glue their ends onto the longer paddle piece. You’ll need to make sure the glue is dried and the wheels are firmly attached before proceeding.
- Loop your rubber band over the width of the boat, across the opening in the center of the boat.Fun Fact: The rubber band is what stores the energy that the boat uses to move the paddle. When you wind the rubber band up it is filled with potential energy. Potential energy is energy that is stored, but hasn’t been released yet. When you release the rubber band the potential energy is converted to kinetic energy and the paddle starts to spin. Kinetic energy is energy in motion — like turning this paddlewheel.
- If you want to create an even snugger fit, and are comfortable sawing, you can saw small notches (about half the width of the side popsicle sticks) into each side of the boat, on and track the rubber band into those notches.
- Fill up a sink or a bathtub with water.
- Insert one of the blades of the paddle wheel into the rubber band, and wind it up in the rubber band until the rubber band feels tense.
- Holding onto the paddle wheel, place the boat into the water.
- Let go of the paddle wheel, and watch your boat take off across the water!
- Whoa!Fun Fact: This works because like a fan, a propeller on a boat transfers energy by transforming rotational motion into thrust, or propulsive motion. The spinning of the propeller accelerates the water to make force that pushes the boat forward.
Questions for your kids and teens.
- What would happen if you made the point with a flat front, instead of a pointed one?
- How much larger could you have made your paddlewheel? If you wanted to make a much larger one, how would you need to restructure your boat?
- If you wanted to secure your rubber band differently, could you tie it somehow? Or loop it around something?
- This boat had three layers, but what do you think would happen if it had five layers? Or ten layers? Or one layer?
Investigate and Explore
Take what you've learned to the next level to learn more and explore the possibilities.
3-D printing is quickly becoming not just a novelty or something used in limited industrial applications, and instead is become more accessible to consumers, and more widely used by companies of all kinds to create a wide array of products – and is even being experimented with to create new human body parts.
What you’ve created in this exercise is pretty similar to how 3-D printers create any kind of object by putting down successive layers, following instructions from a digital design program. But that also means leaving spaces when they need to, just like you left space in the middle for your paddlewheel. Watch the video on this page to see how Joseph Huff, the 2020 4-H Youth in Action Award winner, used a 3-D printer to create a machine-printed paddlewheel boat.
On the flip side of your experiment, you made a boat that floats in the water – out of popsicle sticks! That might sound crazy, but anything that weighs less than the amount of water it displaces (pushes aside) can float. Of course, if you left your popsicle-stick boat in the water for an hour, it might soak up a lot of water and sink – because the added weight of the water in the popsicle sticks would make the boat weigh more than the amount of water it displaces.
Watch Joseph Huff design and build a paddlewheel boat with a 3-D printer
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