Mark Rober, a NASA engineer turned coolest-uncle-ever, wanted to see what it was like to jump into a pool filled with 25 million Orbeez (we’re assuming he guesstimated, and he didn’t really count by hand). Do people sink or float? With the help of the Backyard Scientist’s pool, Mark tested his hypothesis: That he’ll only sink to his waist. Watch what happens and share it with the kiddos (but be prepared that they will so want to try this at home!).

Video: Mark Rober via YouTube

 

So cool, right? What’s your favorite pool-time activity? Let us know in the comments below!