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 Skateboarding may have started out as just another hobby. Now, though, it is a huge industry with state of the art equipment and international competitions.
So how did a humble plank of wood become transformed into the technological marvel it is today? Over the years, designers worked on the separate components - the deck, the wheels and the trucks (the bit which connects the wheels and the deck and allows it to turn) - to come up with the modern skateboard. Engineers have designed the "perfect" board using computer-simulated models to develop the ultimate skateboard with the "perfect" ride.
The board may be a feat of engineering but – the tricks are pure physics.
 Skateboarding Science
Some people think skateboards are just planks of wood with wheels, others know they are highly-engineered devices that have been honed and developed down the years.
Modern skateboard decks are made from seven layers of sugar maple veneer pressed together using polyvinyl glue in either aluminium, metal or concrete forms. The boards are put in a press to form a compound curve – the characteristic shape of a modern board. With all the modern materials available, true professionals still find sugar maple wood better than fibreglass and carbon-loaded thermo plastics.
The board shape has evolved as riding styles have changed. Boards were originally flat and wide with no nose - because all people wanted to do was go forward. When skateboard parks were introduced in the late 1970s, the board designs narrowed and began to curve.
The wheels play a major part in the riding experience. Early wheels were made of steel and offered little traction, which limited the number of tricks which could be done. Clay wheels were next but they were not much better. In the 1970s urethane wheels made the whole ride smoother and easier to control. Urethane is tough and durable and has good traction, making the board go very fast. Adding pigments or dyes to urethane can alter its structure making it weaker, so true professionals always opt for naturally-coloured wheels.
 Even though new wheel design revolutionised skating, the bearings still proved a problem. They often became damaged by sand and grit making them roll badly as they wore out. But in the mid 1970s bearings were developed that sat either side of the axle. The combined affect of urethane wheels and precision bearings transformed skateboards into the modern riding machines they are today.
Steering is down to the trucks which are attached to the underside of the board, and to the wheels, via an axle which allows the wheel to swing. By leaning to the left or right you can change the direction of travel. A kingpin nut controls turning. By tightening the nut the action of the truck becomes stiffer and harder to turn, and vice versa. The design of the truck has probably reached its peak. The basic model was so sound, he design has not been changed for around 50 years.
But even when you have your ultimate skateboard – just how do you stay on it? That’s where the physics comes in.
One of the most amazing tricks in skateboarding is known as the ‘Ollie’. This is when a rider jumps in the air and it looks as though the board is stuck to their feet. So how is this done?
 Just before a skater performs an Ollie there are three forces acting on the board – the weight of the rider, the force of gravity on the board and the force of the ground pushing up on the board. Before a skater performs the jump, they will crouch down low, creating a low centre of mass on the board, then accelerate upwards by straightening out their legs and raising their arms.
During the jump, the rear foot exerts a much greater pressure on the back of the board than the front foot, causing the board to pivot around the rear wheel. As the end of the board hits the ground, the ground exerts a large upward force resulting in the board bouncing up and pivoting around its centre of mass. With the board in the air, the skater slides the front foot forward using the friction between the foot and the rough surface of the board, to drag the board even higher. The skater then begins to push their front foot down, raising the rear wheels and levelling out the board. When an ‘Ollie’ is done properly it look like the board is "stuck" to their feet.
Great skateboard design is about function, not fashion. And for that, the best boards and the best skaters rely on good science.
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