How Fuel Cells Work. Polymer Electrolyte Membrane (PEM) fuel cells used in automobilesâalso called Proton Exchange Membrane fuel cellsâuse hydrogen fuel and oxygen from the air to produce electricity. The diagram and animation below show how a PEM fuel cell works.
Sound is what happens when you transmit vibrations of energy through that matter. Sound is made up of wave vibrations. When you talk aloud, the motion of your vocal cords causes the air to vibrate. Air is made up of molecules, and as those air molecules vibrate, they hit each other.
The definition of sound is someone or something that is in good condition. An example of sound is a well made chair. Sound is vibration in air and water that stimulate the nerves inside the ears to create the sensation of hearing. An example of sound is music. An example of sound is voices. The definition of a sound is a wide channel or strait linking two large bodies of water.