Water boiling in a beaker releases water vapor. The water vapor bubbles, along with the hotter water rise to the surface of the beaker. The water vapor is released into the
environment, while the cooler water at the surface of the beaker sinks back down. The
process described is known as convection, conduction, fusion, or radiation

Atrain is traveling at 30.0 m/s relative to the ground in still air. the frequency of the note emitted by the train whistle is 262 hz. the speed of sound in air should be taken as 344 m/s. what frequency (f approach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and approaching it? what frequency (f recede) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and receding from it?