Yesterday we had a water balloon fight!
This year, I had plenty of help filling up balloons! We had an assembly line, so it went a lot faster. One person got the balloon from the package and pulling it in order to stretch it out, one person filling up the balloon with water, one tying it, and Max would then put it in the bin.
We found that balloons have elasticity, which was improved by stretching it first. Otherwise, the balloon might not stretch enough to let the water in.
Filling up the balloons showed that water has mass (it takes up space)
The neighbors started throwing balloons over the fence...