How a swimming race works

Shown with freestyle, where almost everyone swims front crawl.

1. Each swimmer races in their own lane for the full distance, from 50 m up to 1500 m at the Olympics.
2. The start is a dive. On "take your marks" the swimmers hold still, then the starter's signal sends them off. A swimmer who goes early can be disqualified, with no second chance.
3. At every turn and at the finish the swimmer must touch the wall.
4. The touch on the wall's touch panel stops the clock. Times are taken to a hundredth of a second, and a tie shares the place.

How a meet runs

Swimmers go through on time, not on where they finish in their own heat: the fastest from the heats reach the semi-finals, and the fastest eight from those reach the final. The fastest qualifier swims in lane 4.