Crack Facts

When glass breaks, the cracks move at speeds of up to 3,000 miles per hour.

The sound you hear when you crack your knuckles is actually caused by a gas bubble rapidly forming in the joint fluid, not bubbles popping.

When glass breaks, the cracks move faster than 3,000 miles per hour. To photograph the event, a camera must shoot at a millionth of a second!

When glass breaks, the cracks move faster than 3,000 miles per hour.