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Family Fun with Physics: Launching Plastic Eggs with the Ping Pong Catapult

The ping pong catapult is a great device for independent student science projects, but this is a tool you can use again and again—even as the basis for a fun afternoon or weekend family science activity. We put the rubber band catapult to use with a bag of plastic eggs for some high-flying family physics fun!

Ping Pong Catapult with Plastic Eggs experiment / family science activity

The Ping Pong Catapult has been used as the basis of a number of innovative science physics, math, and sports science projects at Science Buddies. If your student has an affinity for medieval lore, you can imagine using the device as catapults were once used—for siege—and explore the physics of trajectory through a hands-on simulation. In the Bombs Away! A Ping Pong Catapult project, students aim for a simple container target (e.g., shoe box), but for fun, you could create a castle from blocks, LEGO® bricks, or random household items or recycled containers, and either aim to knock the structure down with your ping pong ball attack or aim to launch over the structure (e.g., village walls) and into a target container (e.g., the village square or main castle). (See Under Siege! Use a Catapult to Storm Castle Walls for a project like this!)

Is your student more sports-minded than medieval? With a makeshift footfall field goal in place, you can explore kicking science, or, turn the catapult on its side and do an experiment related to baseball swings instead.

There are plenty of math and physics questions to ask and investigate using the Ping Pong Catapult (available in the Science Buddies Store). With all of these projects, keeping track of the data for every launch, hit, or kick is an important part of the exploration. Teachers and parents can easily turn the results of even informal ping pong catapult launches into a way to talk about statistics, including creating a histogram to plot results.

Before or after the school science project, however, you can use the catapult as a great indoor or outdoor science toy. My kids couldn't wait to get it out of the box and start launching balls through the house. (Be careful that they don't end up "lost" in the living room before your project or science activity starts!)

Portable, No-mess Science Setup!

Unlike some science activities, there is virtually zero setup with the catapult. Remove the pin, unfold it, replace the pin, slip a rubber band through the holes, and clamp the catapult to the edge of a table or chair. We were not planning to experiment right away, but my students were really eager to see how the catapult worked. Immediately after opening the kit, we cleared a table edge, clamped the catapult in place, and played around with the wiffle and ping pong balls and got a feel for how the catapult works, how you change the launch angle and pull-back angle separately, and how the use of the rubber bands can affect the way the object flies.

With just a bit of hands-on exploration at the dining room table, we were all set for some serious egg-flying fun. Plastic eggs, that is. (Your mileage and mess with real eggs may vary!)

You Don't Have to Have an Assignment

The great thing about family science is that you don't have to follow all the rules, do dozens of trials, or write a report at the end. You can take your family science as far and as deep as you want and tailor the activity to fit your students' interests, the time of the year, the materials on hand, or other parameters.

Easter is this week, so we decided to use the catapult with plastic eggs—much as you would experiment with the ping pong ball in the Bombs Away project. We spruced up some of the eggs we have collected over the past dozen years with zany permanent-marker faces and got ready to let the eggs fly.

We first did our launch trials indoors. Instead of using a big table, we clamped the catapult to a small wooden chair. As they quickly realized, getting the egg into the target "basket" is harder than it looks! But tweaking the angles is all part of the exploration, and with each change you make, you can immediately see what impact the change makes (if any) on the flight, trajectory, and distance. After experimenting with pullback and launch angles, they started tweaking the number of rubber bands. This resulted in eggs being hurled full force into the wall (well beyond the basket). They thought that was funny, but it prompted us to consider taking the project outdoors the next day and experimenting in a bigger space.

We packed the small chair, a basket of eggs, and the catapult in the car and headed to a neighborhood park. There were birthday parties going on in the grassy area, but the basketball court was unused. We set up our catapult (still using the wooden chair) on the court, put the basket a distance away, and let loose. The dynamics of outdoor flight were definitely different, and the breezy day made controlling the flight difficult. But it was still super fun!

Your Own Ping Pong Catapult Experiment

To experiment with the catapult for a science project or informal science activity of your own, see the following projects and ideas:

We would love to see your catapult in action! Share your photos with

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