Diy Kid Friendly Newton's Cradle

DIY Kid Friendly Newton's Cradle
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Super easy, kid-friendly Newton's Cradle craft project.

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Bored at home and looking for something to do or make with your kids? Then how about a DIY friendly, easy to create Newton's Cradle that you can build with your kids in just a few minutes!

What is a Newton's Cradle you ask? It's a device that demonstrates conservation of momentum and energy by using a set of swinging balls. It was named after Sir Isaac Newton, remember him? He was the one who essentially "discovered" gravity one day while sitting under a tree and having an apple fall on his head. We'll leave the debate on the authenticity of that story for another time.

It's also often called Newton's Balls (but you can see how that might get weird fast) or an Executive Ball Clicker. The idea is that you lift one ball on the end, release it, and as it smacks the next ball the force is transmitted through several balls until the one on the opposite end pops up.

What You'll Need

This is a pretty simple project for most ages. Since we're dealing with kids we decided to make ours out of building blocks. We went with some Trio-Blocks but Legos and other items would work. You could even use cardboard, PVC pipes, wood scraps, and so on. It just depends on how permanent of a device you want.

You'll then need five balls. You want a hard ball so large steel ball bearings are ideal, but golf balls also work great. Add in some string, thread, or fishing line and you're almost there. You'll also need some way to attach the line to the balls, we chose a (low-temp) hot glue gun since it's fast, easy, and can be removed later. For younger kids you could use tape or something like Sugru.

Build The Cradle

Rather than try to describe each step of building the cradle, you want a structure like you see above. Picture a rectangular box with all of the side and top panels removed but the outline of that box still in place. That's the basic structure, though many designs get artsy and fancy.

Attach String

Next, get a length of your string (or thread or fishing line). The length depends on how big you're building but should become obvious based on the photos you see here. Cut the string long and you can trim it later. Now find the middle of the string and that's where you ball gets attached (again, hot glue with adult supervision is the fast option here).

Once dry, you'll attach both ends of the string to the two top rails. We used tape for this so it would easily come apart later. You're basically making a "U" shape from one rail to the other / opposite rail. The goal is to get the ball to hang right in the center of the two rails, about an inch or two off the bottom of the base.

Rinse, Repeat.

Do exactly what you did four more times so you have a total of five balls. As you hang balls 2-5 you'll want to make sure they're centered and placed so each balls is touching (without pushing) the ball next to it. This entire device requires that all five balls are all touching / resting on each other.


If you did well, all of the five balls will be lined up as you look down the end of the cradle. Now give it a try by pulling up one of the two end balls and releasing it. Neat, huh? Now try pulling up three balls together and releasing all three at the same time. Even neater, right? Physics! Science! There's a lot that can be learned here, but it's really just fun to play with.