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.
Wavelength vs Frequency. Sound is the vibration of pressure in the form of mechanical waves or sound waves which are transmitted through any form of matter whether solid, liquid, or gas.peed of sound which is the distance travelled by sound waves. Wavenumber which is the property of a wave. Wavelength which is the distance between each sound wave. Frequency which is the number of times a sound wave occurs.