How do spiders make webs spanning large distances

[boothiw]

How do garden spiders get their webs to span relatively large distances? Presumably they cant jump, so how do they get the first strand across?

[tief]

The spider releases a fine thread into the air and waits for air currents to carry it away until it catches on something. (Even in still air there are tiny currents occurring which are enough to do the job.) The thread is light enough to be carried on a 'puff' of air, sticky enough to catch and hold, and just strong enough to bear the spider's weight. The spider tests the thread's hold, then usually crosses back and forth over it a few times, strengthening it. From this baseline it commences to spin its web.