The Breakdown

Shopping Cart Science

Sometimes it hurts to be reminded of fundamental principles of physics

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.

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Make A Wish

Popular Science looks at the science of shooting stars

In the first video we see footage of a fireball generated by a large meteor recently sighted careening over the skies of western Canada. Impressively bright! Since we get only a brief glimpse of the action we've also included another amazing video, below, of a meteor streaking over Guadalajara. It's a common misconception that the heat generated from meteors impacting the atmosphere is due to friction. In fact it's due to a thermodynamic process known as adiabatic compression. Let's see how this works.

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Getting the Drift

The physics of losing traction

Recently I was watching the animated movie "Cars" with my automobile-obsessed four-year-old son, when an interesting and unexpected physics item made an appearance in one of the scenes.

Lightning McQueen, the arrogant young protagonist race car, is astonished when he can't make a left turn on a dirt track. When "Doc" explains that McQueen must turn right to go left, Lightning is annoyed and dumbfounded by the seemingly ridiculous logic of Doc's proposition. But Doc is right (no pun intended). What he is describing is the phenomenon known as "drifting."

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Japanese Binocular Soccer

Another rollicking physics demonstration from Japanese TV

I was very pleased to find out about the existence of "binocular soccer". It's a whimsical, silly romp, another manifestation of that distinctly Japanese sense of humor. Check out "human Tetris" for another delight in the same genre. The inherent difficulty of playing this game has much to do with fundamental principles of optics.

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The Physics of Surfing (Part Two: Tubes and Barrels)

The wave dynamics of serious tube riding

Probably the most sought-after surfing experience is the tube ride (a.k.a. "getting barreled"). A tube ride occurs when the top of the wave pitches over the surfer so that he or she is completely enclosed in an oval space behind the curtain of falling water. Inside the "green room," you are hurtling through a tunnel of water and the only way out (without wiping out) is straight through the opening in front of you. Hollow waves are foot-for-foot the most powerful variety of breaking wave, and good tube riding is really difficult. It requires timing, experience, and skill. The video shows us some world-class surfers making it look easy!

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The Physics of Surfing (Part One: Dropping In)

Catching the biggest waves takes some work

There are few things more impressive than watching a big-wave surfer dropping into a monstrous "bomb" 60 or 70 feet high. Actually doing it must be quite an adrenaline rush. (I've been out in waves maybe a fifth that size and even then the energy of the wave can be, well... terrifying!) In the video we can see that the surfer gets towed into the wave with the aid of a jet ski. If you're familiar with surfing you might be aware that once waves get big enough (wave faces larger than 40 or 50 feet) it's impossible to paddle into them in the "traditional" way: you have to be towed in. Why is this? Not surprisingly, it all has to do with some basic principles of physics.

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Fluid Density and You

Before you jet off to your well-earned beach vacation, read this week's Breakdown

If you've ever been in the ocean in the vicinity of large breaking waves and have been unfortunate enough to get steamrolled by a wall of whitewater, you may have noticed how much more difficult it is to get back up to the surface through the whitewater compared to smooth water. Why is this? While it may be due in part to the difficulty in "gripping" the aerated water (to pull yourself to the surface you have to apply a force downward against the water such that it pushes upward on you), it also has to do with a reduction in your buoyancy, due to the lower density of the whitewater.

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Seeing Red

Physics is your ally as you protect your tiny planet from an onslaught of meteorites

Last week, we investigated the principle of conservation of angular momentum on a spinning carousel. In this episode we illustrate the linear version of the same principle -- conservation of linear momentum -- as illustrated by the physics-based computer game Red. The goal of the game is to avoid being crushed by a relentless barrage of incoming meteorites, by deflecting them with cannon balls. Understanding a little bit about conservation of momentum is a consolation in the face of the reality that sooner or later you are going to get flattened.

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The Science of Spinning

This week, the Breakdown takes a hard look at angular momentum. Don't get dizzy!

Why does a spinning skater speed up when she pulls her arms closer to her body? It's the same phenomenon that causes the carousel in the video to rotate faster when the students move towards the center. And that phenomenon is in fact one of the fundamental principles of physics, known around the planet as "conservation of momentum." Here, in particular, we have a beautiful demonstration of conservation of angular momentum.

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When Is Carbon an Electrical Conductor?

Just ask this poor pencil

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.

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Playing Games With Science: N3wton

Newton's Third Law plays the starring role in this simple but provocative game

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.)

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Popping Power

Can cell phones pop popcorn? Just watch

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.

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Feeling Gravitee's Pull

Who's up for a round of interplanetary golf?

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.

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Playing Games With Science: Magic Pen

Physics you can draw

[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.

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Trampoline Basketball

The science of jumping higher

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