Show Me Some Science! Drum Crush

 In Shopcasts and Videos, Show Me Some Science

A 55 gallon drum is filled with water on the 3rd floor balcony. A hose siphons water to the ground 10 meters (30 feet) below. What happens next will blow your mind!

As the water falls down to the ground the pressure decreases, but the hose on the bottom is open to the air and is the same as the atmospheric pressure; this makes the pressure on the top of the hose decrease well below atmospheric pressure. But the top of the hose is connected to the inside of the drum, so the drum has low pressure on the inside and atmospheric pressure on the outside, which crushes it!

After the big crush we did the opposite experiment! We moved the drum to the ground and siphoned water from an open container on the balcony. The water on top is at the same pressure as the atmosphere, and the pressure increases down the hose and into the drum causing it to re-inflate!


Here’s the same experiment broken up into two short videos.