The float block slows outputs gradually, rather than bringing them to a sudden stop. This can be useful in designing projects like merry-go-rounds, trains, and cars which may need to float motors in order to make them behave more realistically. Floats can also be used to prevent gear grinding. 

Technically, the float works by cutting all power to the output, as opposed to the stop block, which cuts power and brakes the motor. If the float is used with a lamp, it will dim because the power has been cut. A motor will continue to spin after power has been cut for as long as its own momentum can sustain it.

The program below simulates a revving engine: