Just because school is starting soon (or maybe you've started already!) doesn't mean the warm weather fun must end. While you are picking up your back to school supplies, make sure to stop in the cleaning aisle to get a package or two of sponges so you can make some squishy water bombs.
I bought 3 4-packs of basic cleaning sponges. You'll need some zip ties and scissors too.
Cut lengthwise into 3 strips.
Stack 'em. Zip 'em. Cut 'em.
I only did 2 layers for mine, but you can use 3 for a fuller ball.
This is a fun one for kids to help make too, not just to play with.
Inspired by this post.