Pianos lose their tuning, guitars fall out of key -- even church organs need to be tuned every now and then. For centuries, the only sure-fire way to tell if an instrument was in tune was to use a tuning fork.
The idea that something so intangible can lift objects can seem unbelievable, but it's a real phenomenon. Learn how acoustic levitation takes advantage of the properties of sound to cause solids, liquids and heavy gases to float.
Radar seems to have infinite uses: Police use it to clock your speed, NASA uses it to follow satellites, meteorologists use it to track storms and the military uses it to track the enemy ... Learn all about radar technology!