What is the difference between sweeping and sculling?

Within the sport of rowing their are two disciplines: sweeping and sculling.

SWEEP - In sweeping each rower has one oar that is ~12.5 ft long. There are three main sweep boat categories: 8-person (called the eight), 4-person (called the four), and 2-person (called the pair).

SCULL - In sculling each rower has two oars, each ~9.5 feet long. There are three main scull boat categories: 4-person (called the quad or quadruple), 2-person (called the double), 1-person (called the single).

SPEED - The eight and quad are similar speeds. The four and double are similar speeds. The pair and single are similar speeds.