If the passengers on that airplane felt their collective hearts stop for a moment, it wasn't due to the electric current from the lightning strike running through their bodies. In fact, airplanes getting struck by lightning is a fairly common occurrence -- more common than you might realize.

This charming little video demonstrates the principle of resonant frequency using oscillating metronomes. The mechanical wind-up metronomes used worldwide during the dreaded Saturday piano lesson employ an inverted pendulum to keep even time intervals. The resonant frequency of the pendulum is adjusted by moving the mass up and down. Sliding the mass higher up the rod decreases the resonant frequency of the pendulum by increasing its rotational inertia.

While the principle is fairly straightforward, this video is such an endearing representation of the concept of relative motion that we had to share it. Who wouldn't appreciate the lengths they went to do the demonstration, not to mention the dramatic atmosphere of the video!

Skiing off of a 245 foot vertical cliff–looks like fun. It also looks like an insurance disaster in the making. And yet the skiers make it to the other side with nary a scratch. As you doubtless intuitively suspect, they end up ok because of the relatively “soft” snowy landing. As long as the acceleration involved in coming to a stop during impact is not beyond a certain threshold they can survive the fall. According to Newton’s Second Law (F = ma) if you extend the time of impact you reduce the acceleration (a = Δv/Δt) and therefore the force acting on a crazy extreme sport adrenaline junkie. The snow increases both the time and distance over which the collision occurs giving these guys a reasonable chance of walking away alive and without serious internal injuries. So let’s estimate how deep the snow needs to be for a safe landing.

In this video, we see a dramatic demonstration of standing waves patterns, which form when travelling waves constructively and destructively interfere as they pass through one other.

The latest cinematic version of The Incredible Hulk is due to hit theaters soon. Now, many people are aware that the most incredible thing about the Hulk is the way his pants always stay on when he expands to ten times his original volume. (If they didn’t it would make for a completely different kind of superhero.) His brute strength, however, is a close runner-up.

These guys are pretty amazing. And the nonchalance with which they accomplish each trick shot adds a certain understated humor to this entertaining video. But though the guys seem to be developing a seemingly useless (if highly impressive) skill in their spare time, there's quite a bit of complex science at play. In addition to being a highlight at any party, these are excellent demonstrations of two- and three-dimensional projectile motion, and with just a little bit of quantitative analysis the entire video would make a formidable project for an introductory level college physics class.

For example lets look at the segment where the guy tosses the ball in the cup off of a moving skateboard.