VOA慢速英语2014 Hoverboards Ignore Gravity（在线收听）

Hoverboards Ignore Gravity

Can you imagine riding around the streets of your hometown on a skateboard without wheels? In the late 1980s, film director Robert Zemeckis showed a skateboard floating above the ground in his movie Back To The Future Part II.

Now, an American company, Arx Pax, has moved the idea for such a device from a futuristic dream to reality. The new product operates on the same rules that govern magnetism.

When similarly charged ends of two magnets get close together, they repel or push away from each other. That force can make an object levitate or hover in space.

Since the 1980s, levitation has been used on trains in Europe, Japan and China. These maglev trains, seem to float above the ground. There is no contact between the bottom of the cars and the surface of the train track. Maglev trains are almost noiseless and can move very fast.

Greg Henderson says the same technology can make anything hover, even buildings.

“Imagine there's an earthquake and the early warning turns on the warning systems and the supports fall away as the building starts to hover. The shaking stops, the supports return, and no one in that room or in that building ever knew there was an earthquake."

Greg Henderson’s company created the first maglev hoverboard, called Hendo. It can hold a single person about 2.5 centimeters above a metal surface.

"We are creating a magnetic field, and then through a method of induction, that's part of our secret sauce*, we are creating a secondary and equal magnetic field in this conductive surface."

Batteries provide the electricity needed to power Hendo's four engines. However, the batteries only last for a short time. But design engineer Kyle O'Neil says they last long enough for experienced skateboarders to learn how to control the hoverboard.

“Some people say it's like snowboarding. Some say it's how they imagined a hoverboard is supposed to be, which is kind of an interesting response because no one's ever ridden one before.”

Words in This Story

hover – v.  to float in the air

magnetism -  n.  the property of attracting certain metals; the attracting property of a magnet

repel - v. to force (something) to move away or apart

skateboard – n. a short board that is on wheels and that a person stands on to move along a surface or to perform tricks