Inventor and engineer Mark Rober is a pretty sharp guy. He worked for NASA, for Christ’s sake.
Rober recently shared a video on his YouTube channel that you have to see to believe.
Rober demonstrates how adding air to sand in a very specific way causes the sand to look and act like a fluid. So Rober decided to fill up a hot tub with sand and give it a go. He also enlisted his nephews to help him out.
Check out the video below to see this experiment in action.