A spider can produce a silky substance from tiny openings on its underside. To spin a web it starts by making a frame of this silk, attaching it to firm objects, such as twigs.
When the frame is finished, the spider fixes spokes of silk across it, jut like the spokes of a wheel. Then it arranges the sticky spiral thread across these spokes, leaving a platform of non-sticky thread in the middle where it waits for its prey. Though the webs look delicate, they are very strong.