Surfing

Discover the science behind surfing, one of the most popular water sports in the world, where thrill-seekers use the energy of breaking waves to power their manoeuvres.

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As these waves approach the shore, the shallow water forces them to slow down and become taller and steeper

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If they time their paddling just right, the wave will be almost breaking when it reaches the surfer, with a super-steep front face and white froth starting to form at its peak. This happens because the water at the back of the wave is now travelling more quickly than the front of the wave and is starting to overtake it.

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The breaking wave catches the surfer, and they start to fall down the face of the wave. As soon as they can feel that the wave has caught them, they leap up so they are standing on the board, a manoeuvre called the take-off.

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If they manage to take off successfully, the surfer will lean their weight to one side to steer the board sideways along the wave and away from the area where it is breaking. Fins at the back of the board act like sails on a boat, transferring energy to the board from the water so it accelerates. Fins also allow the surfer to control their direction.

Energy from the wind is transferred to the water, causing it to move in a circular motion and creating ocean waves

The first surfboards were carved from tree trunks, making them super-heavy. Most modern boards are made from fibreglass and lightweight foam so they are light and strong – but the plastics and resins they’re made from are bad for the environment. Thankfully, more environmentally friendly boards made from recycled plastics or lightweight balsa wood are becoming popular as surfers try to limit the impact their sport has on the planet.

The best waves for surfing break sideways along their length (rather than all at once). This allows the surfer to surf away from the breaking area and speed along the unbroken face of the wave.

As a surfer whizzes along a wave, lots of complicated physics is at work. The main forces involved are buoyancy and gravity, which control whether the surfer stays on top of the surface of the wave or sinks underwater. Drag between the surface of the water and the surfboard slows the board down.

Some waves break quickly over very shallow water and form a hollow barrel. Surfers can slow themselves down until the breaking wave reaches them and they can ride along inside the wave!