托福听力练习：外太空模拟实验

　　和谐英语网为同学们整理了托福听力练习集锦，供考生参考学习。

　　托福听力练习：外太空模拟实验

　　Located at the NASA Research Center in Iowa is a 5,000-gallon vat of water,and inside the tank is an underwater treadmill designed by Dava Newman, an aerospace engineer.

　　For four years Newman observed scuba divers as they simulated walking on the Moon and on Mars on her underwater moving belt.

　　She wanted to discover how the gravity of the Moon and of Mars would affect human movement.

　　To do this, Newman attached weights to the divers and then lowered them into the tank and onto the treadmill.

　　These weights were carefully adjusted so that the divers could experience underwater the gravity of the Moon and of Mars as they walked on the treadmill.

　　Newman concluded that walking on Mars will probably be easier than walking on the Moon.

　　The Moon has less gravity than Mars does, so at lunar gravity, the divers struggled to keep their balance andwalked awkwardly.

　　But at Martian gravity, the divers had greater traction and stability and could easily adjust to a pace of1.5 miles per hour.

　　As Newman gradually increased the speed of the treadmill, the divers took longer, graceful strides until theycomfortably settled into an even quicker pace.

　　Newman also noted that at Martian gravity, the divers needed less oxygen.

　　The data Newman collected will help in the future design of Martian space suits.

　　Compared to lunar space suits, Martian space suits will require smaller air tanks; and, to allow for freermovement, the elbow and knee areas of the space suits will also be altered.

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