STEM Challenge: Float Your Boat

Hi everyone, Kirk here from Lakeshore. Welcome to today's learning at home STEM challenge. Have you ever wondered why boats can float? Especially those really big ones with tons and tons of containers? How can something that heavy just sit on top of water? Well today, you're going to design your very own boat that can hold up something heavy. Before we begin, I have something pretty interesting I want to show you. Here I have a penny and a piece of aluminum foil. They're both metal, one is small and round, one is large and square. They're both kind of flat. But what do you think will happen if I put them in water? Let's see. Oh, the penny sunk and the aluminum foil stayed afloat. Now that is interesting. Now you may be thinking, wait a minute, the penny is heavier, so of course it's going to sink. Well I want to show you something interesting. The foil is still on top of the water, but as soon as you push it down, it too will start to sink. See that? Now here's something even more interesting. If I take another piece of foil about the same size and I crumple it up in the air and I take the foil in the water and crumple that up, put them together in the water, what do you think is going to happen when I let go? One floats and one sinks. Now isn't that interesting? It's the same material, same weight, same shape. As you can see, weight isn't the only thing that determines what sinks and floats. Those two balls were about the same size, shape and weight, except for one floated to the top and the other sank to the bottom. Why do you think that happened? The one that floated to the top had air trapped inside. Very interesting. Today we're going to design our very own boat out of aluminum foil that can hold up to 25 pence. But before we begin, parents, here's how you can help. Your kids are going to need some aluminum foil. For older kids, challenge them to do this with about five inch by five inch squares of aluminum foil. They're also going to need 25 pennies. Now the pennies may be dirty, so you might want to wash them with dish soap and water before giving them to your kid. A tub or a bowl filled about three quarters of the way with water. Make sure you have at least two inches of water in there so the boats can fully sink. Help your kids create a simple table on a piece of paper to record their results. It can look something like this. They'll also need a pencil to draw out their boats and record their results. Now this challenge uses water, so spills may be inevitable. Make sure your kids have a safe place to test their boats and a towel nearby in case anything happens. The key to this challenge is observation. Encourage your kids to carefully watch their boat as they add the pennies and especially when it sinks. Think about how did it sink and what could they do next. Drawing out each design and how many pennies it can hold will be a great way to help them problem solve towards a successful solution. Check in on them from time to time. Ask some questions like, which boat held the most coins so far? Which one held the least? What do you think is different between the two? And again, most importantly, what do you plan to do next? Now that you have your materials together, let's get started. The first thing we're going to do is come up with an idea of what we want our boat to look like. That's called the design. So let's think about all the boats that we've seen before. You got really big ones, we've got small ones, we've got tall ones, we've got long ones. Well each of those boats started off with something called a blueprint. A blueprint is a drawing that shows what the boat's going to look like before it's built. Now we're going to do the same thing. Take your pencil and your piece of paper and draw on the left side what you want your boat to look like. I'm going to start with something pretty simple, like a raft. Now let's go to make it. Take your foil, take a piece of foil and cut it, tear it out about the size you want. Now the first test is to see if this boat is even going to float. So put in your water. Does it float? Sure does. Now let's add the weight. So take some pennies and add them to your boat, counting out as you add each one. One, two, three, four, five, six, seven, eight, nine pennies. And then the boat sank. So next we're going to write that down on our paper next to our boat design. Okay so my boat could only hold about nine pennies before it sank. Not the best. Were you watching carefully when it sank though? What do you think the problem was? Let's take another look. And there it goes. What happened? I want you to think up a new design, draw it on your piece of paper, build your boat out of aluminum foil, test it with pennies, and then record the results. And repeat that process until you come up with a successful boat that can hold up to 25 pennies. Now older kids, your challenge is a little bit harder. You can only use a five inch by five inch sheet of aluminum foil, but it has to hold up to 35 pennies. Think you can do it? Let's give it a shot. I just finished testing a couple boat designs and one of them was able to hold 47 pennies before it sank. It's pretty good. Think you could beat that? This is Kirk with Lakeshore. I'll see you next time on another Learning at Home STEM challenge. Take care. Keep watching our Learning at Home videos, plus visit lakeshorelearning.com for thousands of free resources.