Liquid Nitrogen & Ping Pong Balls: Explosion Showcased In Classroom VIDEO

What happens when you combine a garbage bin, liquid nitrogen and 1,500 ping pong balls? Before you find out, University of Plymouth chemistry professor Dr. Roy Lowry advises, "have your hands over your ears."

In a YouTube video taken during one of Lowry's classes, the professor places a sealed container of liquid nitrogen in a large trash bin with some warm water at the bottom. He then pours in two large bags of ping pong balls.

After a few moments of suspense, the action happens (at the 3:50 mark in the video). We won't spoil the surprise, but here's the science: the event results from the pressure in the tightly sealed container of liquid nitrogen. Lowry explains: "The liquid [nitrogen] will turn into gas, and the pressure will build up and up and up."

Apparently Lowry has a thing for big booms. In 2006, he held the Guiness world record for the largest number of rockets launched simultaneously, the BBC News reported.