Part of the show Andrew Bradley discusses Organ Transplantation
Do you like skiing or snowboarding, and would like to learn, but you're scared that you'll end up hurtling helplessly downhill, out of control, and injuring yourself ? Luckily, help is at hand for newcomers to the pistes with the invention of skis and snowboards with built-in electronic brakes that slow them down before things get too scary. The new braking system is being developed by Victor Petrenko, an American engineer. His idea involves running a pair of wires the length of the board or ski's underside, one at each edge. The wires are connected to opposite terminals of a 3-volt battery, making one wire positive and the other negative. Fingers branching off the wires every few millimetres form an intersecting series of positive and negative electrodes covering the entire underside of the snowboard or ski. So how does this help to slow you down ? Well, when the positive electrode comes into contact with compact snow it induces a negative charge at the surface, and in the same way, the negative electrode induces a positive charge in the snow. Because opposite charges attract, this pulls the board closer to the snow and increases friction. You can actually demonstrate this yourself at home by combing your hair, and then using the comb to pick up small pieces of tissue paper, or rubbing a balloon on your hair, and then 'sticking' it to the wall. But that's not all, because the brakes also use another trick to slow you down: at the same time, a tiny current flows through the snow touching the skis between the electrodes, and melts it, rather like the electric windscreen in a car. When the snow melts, the circuit breaks and the melted snow immediately re-freezes, sticking to the ski and massively slowing it down. According to Petrenko, "the change in friction you get is equivalent to going from being on ice to dry pavement." He is now working with a snowboard manufacturer and hopes that snowboards fitted with his brakes will be available next year. A sensor fitted to the boards will monitor the board's speed over the ice, and switch the brakes on if it's going too fast. Petrenko expects his idea to find a ready market. Indeed, skis and snowboards aren't the only surfaces that need to get a grip on snow. Petrenko's next aim is to build shoes and car tyres incorporating similar electronic mechanisms.