阅读今天的推送，看 elastic 出现的一个语境，顺便了解一点粗浅的科学知识吧。
THE POWER OF STRETCH
Pull back on a catapult and the force you use stretches the elastic. This stores energy inside it, known as potential energy. When you let go, the elastic returns to its original shape. The stored energy must go somewhere — so it is given to the stone, flinging it through the air.
▸ catapult 弹弓；石弩
▸ elastic 松紧带，橡皮带
▸ potential energy 势能
▸ fling 扔，抛，丢
Pinch your skin and let go and it springs straight back again. This is because young skin is very elastic. Older skin is not so elastic, which is why older people have more wrinkles. Anti-wrinkle creams work by covering skin in gluey chemicals that stretch it tight. This makes wrinkles disappear — at least for a time.
▸ pinch 拧，掐
▸ spring 跳跃，蹦跳
▸ anti-wrinkle cream 抗皱霜
▸ gluey 胶黏的，涂满胶的
Rubber can be stretched to three times its length. Hydrogels, the world’s stretchiest materials, can be pulled to 20 times their original length.
▸ hydrogel 水凝胶
MAKING RUBBER STRONGER
Rubber comes from trees, and it is white, gooey, and smelly. This pure kind of rubber, called latex, is used to make stretchy things like balloons, but it is not very strong. We can make rubber more useful by cooking it with sulphur. This makes the rubber hard, black, and tough. It is not as stretchy, but it is stronger and lasts longer.
▸ gooey 软而黏的，黏糊糊的
▸ latex 乳胶，橡胶
▸ sulphur 硫磺
The molecules inside the rubber pull far apart and spring back to shape.
Sulphur bridges between molecules make the rubber harder to stretch, but tougher.
▸ sulphur bridge 双硫键
以上英文内容摘自儿童读物 Science, a children's encyclopedia。本书装帧讲究、排版舒服、框架清晰、配图精美，语言简练，内容充实。若喜欢本书内容，请购买原版书。返回主界面回复“科学”查看已推送过的本书内容。