With nothing more than a two-by-four on roller-skate wheels, the sidewalk surfers of the 30s, 40s, and 50s had a straightforward mission: Start at the top of a hill and ride down. The primary goal was just to stay on and avoid collisions; given the humble equipment and rough road conditions, it was no small challenge. Now, thanks in part to improvements in design and materials, skateboarders have a higher calling.

In a blur of flying acrobatics, skaters leap and skid over and onto obstacles, executing flips and turns of ever increasing complexity--all at top speeds. For onlookers and beginners, it can be hard to follow the action, let alone answer the question that springs naturally to mind: How on earth do they do that? While it may seem that modern skateboarders are defying the laws of physics, the truth is that they're just using them to their advantage. Let's take a closer look at some fundamental skateboarding moves and the physics principles behind them.

Invented in the late 1970s by Alan "Ollie" Gelfand, the ollie has become a skateboarding fundamental, the basis for many other more complicated tricks.
In its simplest form, the ollie is a jumping technique that allows skaters to hop over obstacles and onto curbs, etc. What's so amazing about the ollie is the way the skateboard seems to stick to the skater's feet in midair. Seeing pictures of skaters performing soaring 4-foot ollies, many people assume that the board is somehow attached to the skater's feet. It's not. What's even more amazing about the ollie is that to get the skateboard to jump up, the skater pushes down on the board! The secret to this paradoxical maneuver is rotation around multiple axes. Let's take a closer look.

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