the breakdown

Who isn't amused by the rare and impressive science-savvy party trick? One that involves the potential to risk death death by flinging yourself Superman-like at a bouncy training ball, only to have it pop you back up in an amazingly graceful backflip? Before you cry "Sir Isaac Newton!," here are the physics behind this seemingly impossible stunt.

First of all, let's set the record straight. Man is a natural long distance runner. Despite impressions to the contrary foisted on us daily from our predominantly sedentary and "well-fed" modern lifestyle, it is interesting to note that for long enough distances a well-trained human can outrun just about any other creature on the planet.

Of course, recognizing the health benefits of exercise, not all of us live a sedentary life, and running has become a popular form of physical activity. In addition to the exercise aspects, however, those of us with a competitive or goal-oriented nature, from the elite athlete to the recreational runner, might be interested in running faster. Obviously accomplishing a 5K personal best or qualifying for the Boston Marathon requires a solid training program and a substantial amount of hard work. But what about those incidentals that might enhance our ability to train and thus augment our performance on race day? (We're not talking about performance-enhancing drugs here.)

That's where the video comes in.

Most years in my physics courses we construct water bottle rockets as a class project; but this stunt takes bottle rocketry to new levels. We never considered launching actual people!

Is it magic? Is that aluminum foil boat floating on air? Well, no and no. What we literally don't see is that the bottom of that aquarium is filled with sulfur hexafluoride (SF₆). Sulfur hexafluoride is a relatively nonreactive gas that has a density of about five times that of air. It's also transparent.

Here we have a beautifully illustrated example of Newton's First Law of motion involving shopping carts. Did some force push those carts out the back end of the trailer? Not at all.

And the $64,000 question is ... does graphite conduct electricity? It certainly does! The video demonstration displays this quite convincingly. Graphite is an interesting material, an allotrope of carbon (as is diamond). It displays properties of both metals, and nonmetals. However, like a metal, graphite is a very good conductor of electricity due to the mobility of the electrons in its outer valence shells.

Newton's Third Law is often quoted as "For every action there is an equal and opposite reaction." As N3wton's title suggests, the Third Law is at the heart of this little physics-oriented computer game. Click to play. (Warning: there's music.)

Let's set the record straight. This first video is a clever hoax. It is not possible to pop popcorn using cell phones. See how it's done in the second video.

When playing golf in outer space, it's important to keep in mind Newton's Universal Law of Gravitation:

F = Gm₁m₂ / r²

This equation describes the force of gravity between any two masses separated by a distance r between their centers. G is a constant of nature that we call the universal gravitational constant.

See it in action in this week's online game, Gravitee.

[Via Diggy Games]

Welcome to Magic Pen. This fascinating little game displays a delightful plethora of physics principles in action. The object of Magic Pen -- as in some similar games, like Crayon Physics Deluxe -- is to roll a ball into a goal. The catch is that you can't touch the ball directly: you can only interact with it by drawing shapes with the mouse. These shapes then interact with the ball, obeying basic principles of physics. For example, draw a rock. The rock then falls due to gravity, collides with the ball, and pushes it towards the goal, which is marked by a flag.