Here at Robot Test Kitchen, we’re big proponents of learning from failure. Sometimes I take it a step further and see a fail as a challenge, and that was the case with DIY Bouncy Balls. After reading Heather’s post and seeing that picture of cup full of multicolored goo, I knew it was something I would eventually try, and I finally got around to it this week. I knew it would be a challenge, and I started by googling “DIY Bouncy Ball Fail” and read through a few of the results before coming up with my hypothesis — it all hinges on finding the right amount of cornstarch. I experimented with several batches before coming up with the best proportions and technique. This is not a difficult project, but it is tricky to get it to work, and I wouldn’t have been able to do it this effectively if so many people hadn’t graciously and/or humorously shared their struggles (Thank you, Heather!).

Did I have any difficulties? You bet. I capped the program registration at 16, but I ended up with 25 (I had enough supplies on hand, but it took a lot more running around —  a couple of amazing parents pitched in to help out). I left the bouncy balls I made the day before the program out on a shelf and that’s how I learned you really need to keep them in a ziploc baggie or they’ll harden; my program attendees just had to take my word that the colorful rocks I showed them had been bouncy the previous day. And of course, as any youth librarian who has ever presented children with cornstarch, Borax, glue and food coloring knows, there was a lot of cleanup involved.

Ball 1 ended up being the bounciest; by reducing the cornstarch in attempts 2-3, they didn’t retain their structure. Ball 4 was the most pleasantly round yet still bouncy.

So here’s my recipe:

1. In the first cup, combine 1/2 teaspoon Borax with 1 Tablespoon VERY WARM water. Stir well.
2. In the second cup, combine 1 Tablespoon glue, 1 Tablespoon cornstarch, and a few drops of food coloring. Stir well.
3. Pour the water/Borax solution into the glue/cornstarch solution and stir; it will quickly form into a nice glob.
4. Remove the glob from the cup, shake off excess water, and roll it into a ball between your hands. It helps to blot the ball and your hands with a paper towel.
5. Once it’s rolled and blotted enough, it should bounce quite well. Manage your expectations though — this is all about learning and creating, and the ball will not be the same as the kind you get in a vending machine for a quarter.
6. Store it in a ziploc baggie.

Overall, it was definitely worth the mess.