The webs that spiders build to catch insects seem weak. However, the strength of spider thread is greater than steel (钢铁). Webs can even stand up to very strong storms.
In each spider web, some threads are sticky, but some are not. When a spider is moving on the web, it will not step on the sticky threads. After a time the silk will lose its stickiness and become unable to catch insects. Then, spiders usually eat their own web.
Now a team of scientists has worked out why the spider web is so strong. It is not just the strength of the thread, but the clever design of the web. "The key to a web's success is its ability to keep its shape and strength even after some of the threads break," said scientists at the Massachusetts Institute of Technology (麻省理工学院). The scientists found the thread itself has the ability to become softer or harder. So it can hold different types of heavy things.
In tests, scientists used three other strong materials made into the same webs. The spider thread was six times stronger than any other material. More surprisingly, when the scientists took away up to 10 percent of the threads from different places, the web didn't become any weaker. Actually, it became up to 10 percent stronger.
The spider web's clever design gives scientists many new ideas. The findings could help design safer buildings and even a new type of strong material. "It's a really good chance," said Markus Buehler, a professor at MIT. " It may give us some new ideas for engineering. "
a. the spider's thread is sticky
b. the thread has a lot of strength
c. the web has a clever design
d. the web can keep the strength forever
