The Slow Mo Guys, a tremendously popular YouTube channel, it’s also incredibly interesting in a scientific way. In this occasion, they use their powerful cameras to demonstrate that glass is actually a liquid.
They took a hammer to a mirror to show what happens in the milliseconds after metal strikes glass. At 2,000 frames-per-second it was hard to see anything other than the instant shattering of the pane. However, everything changed at 120,000 frames-per-second.
First of all, the hammer looked like it wasn’t even moving. But suddenly, when it hit the glass, a shock wave spread out from the point of impact before the glass broke.
As they noted in the video, what happened is really similar to the scene from The Matrix when a helicopter crashes into the side of the skyscraper, setting off a tidal wave of glass before the windows explode.