Hi there! If you haven’t met us before, I’m Bill, and I’m Webb. We’ve been on SciShow Kids before, where we talked about things that think and flow. Today, we’re going to have some fun by making a boat that floats! We’ll also test our boat to see how much it can hold before it sinks.
Our friend, the giant squid Stravaganza, once asked Jesse how boats can float. We learned that boats float because of something called displacement. Displacement happens when an object moves water aside to take up space. For example, when you get into a bathtub, the water rises because you’re displacing it. Just be careful not to get the floor wet!
Now that we’re ready to think like scientists, let’s make a boat! What kind of boat should we make? I always see people paddling around in canoes, so let’s make our own canoes. It’ll be fun!
We’ll get some help from our friends Sophie and Zayn. Here’s what we’ll need: aluminum foil, tape, and scissors. If you’re using scissors, make sure to tell a grown-up for safety.
First, cut a few pieces of foil to make your canoe. Take a piece of foil and bend it in the middle. Shape the two ends and pinch them so they point up. You might need more foil and tape to get the shape you want. Make sure the two ends are taller than the middle. Yahoo, we finished our canoe!
Now it’s time to test our canoes. We’ll fill them with marbles until they sink. You can use rocks, toys, or anything else that’s okay to get wet. We’ll keep track of how many marbles it takes to make each canoe sink. Ready? Here we go!
Wow, look at it go! Can you believe it? One boat held 59 marbles, and the other held 101 marbles. But why did our canoe sink?
Boats float as long as the water they displace weighs the same as the boat. When we added more marbles, the canoe got heavier and sank lower into the water, displacing more water. But when we added that final marble, the canoe weighed more than the water it could push aside, so it sank.
Try making boats of different shapes and sizes. Do some float better than others? Can you build a boat that holds more than our canoe without sinking? If you make a boat and want to share it with us, grab a grown-up and send us an email at kidscyshow.com or leave a comment below.
Thanks to Google Making Science for helping us make this episode. Thanks for joining us on SciShow Kids. Bye! We’ll see you later!
Experiment with Different Materials: Gather various materials like plastic cups, paper, and cork. Try making boats with these materials and test them in water. Which material makes the best floating boat? Why do you think that is? Discuss with a friend or family member what you observed.
Design Your Own Boat: Using clay or playdough, design a boat of your own shape and size. Once you’ve made your boat, test it by adding small objects like coins or pebbles. How many can it hold before it sinks? Try reshaping your boat to see if it can hold more. What changes helped it float better?
Observe Displacement in Action: Fill a clear container with water and mark the water level. Gently place a small toy or object in the water and watch how the water level rises. Can you explain why this happens? Try using different objects and see how much the water level changes with each one. Which object displaced the most water?
