Inertia Zoom Ball: Super Fun S.T.E.A.M. Project!

Have you ever heard of an inertia zoom ball? Yeah, me neither! When researching the theme "react" for this week's S.T.E.A.M. based project (did you see our diy indoor boomerangs last week?) I happened across this activity. It looked exactly like something my boys would enjoy doing. Plus, let's face it, anything with the words "zoom" and "ball" is going to get the attention of my kids.

If you are looking for a science project that is perfect for ACTIVE kids this is the one. No need to worry about spilled chemicals or sticky messes, lots of prep time or hunting around for all those elusive materials. This science experiment can be done right now, indoors or out.

How to Make an Inertia Zoom Ball

What you need:

• 2 plastic 1 L bottles. Um, if you don't drink soda you might get them from your neighbor's recycling. Just sayin'. There are benefits to apartment living.  (Yes, I washed them!)
• Scissors
• String
• Craft supplies (optional)

Instructions:

Cut the bottoms off the plastic bottles. I found this to be difficult and had to really jab a sharp point into the plastic to get it started. So, this is probably a job for grown-ups unless your kids are quite a bit older.

Either tape the bottles together, end to end, or slip one end inside the other, which is what we did. This will be the base of your inertia zoom ball.

Optional: decorate your zoom ball. My bird loving son jazzed his up to look like a hyacinth macaw.

Thread two lengths of string through the inertia zoom ball. Make these quite long at first, so your kids can experiment with the effect that shortening the strings may have on the reaction of the ball.

How to operate the zoom ball: 

(I tried to make a video but it was too pathetic to share with you. Watch the video below to see how it works! Trust me, your kids will figure it out in two seconds.)

You need two people. So grab the neighbor you stole the plastic bottles from, or tell your kids to stop fighting and get it together so they can do a little science.

Each person takes a hold of one end of each string and pulls them taut. First hold the strings together and move the ball to one end. The person closest to the ball snaps the strings apart and the ball zooms toward the opposite end! The receiver then snaps his string ends open as his partner closes his hands to zoom it back.

Tip: Hold on tight! As  long as either partner doesn't let go, you can get some super zooming action in.

Tip: A fast moving plastic bottle can hurt when it bumps against your hands! Wear mittens.

Tip: We kept forgetting to bring our hands back together after the ball had zoomed away, so we started shouting "Open! Close" Open! Close!". Yes, we did sound a bit dorky.

Tip: Experiment with longer or shorter strings. Talk about the difference!

What's the science?  As the strings push apart, the ball reacts by zooming down the strings. The ball's motion can be halted in several ways: bumping against the hands of the receiver (ouch!), losing momentum when a string goes slack when it is accidentally dropped (as you know, we love learning about science through failure), or, if the reaction of the snapped strings was not strong enough, the ball loses speed as it enters the "straight string zone". (Don't you love my technical language? I was a drama major, people.)

By the way, we found this project is the fantastic and highly useful book, Gizmos & Gadgets: Creating Science Contraptions That Work (& Knowing Why) (affiliate link). Apparently, zoom balls are a hot item in occupational therapy right now, so... BONUS!

Happy Science Play!

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