Transducer, in electronics, a device that converts electric energy into some other form of energy, or vice versa. Transducers are used in sound systems, in video equipment and in many measuring devices. A transducer used in a measuring device produces an electric current proportional to the strength or intensity of the physical quantity—such as heat, light, or mechanical stress—to which the transducer is subjected. Piezoelectric crystals (crystals that produce an electric current when deformed) and photoelectric cells are transducers; so are loudspeakers, which produce sound from electric energy.
Mass spectrometry enables the major league to sniff out athletes guilty of doping. It can also help us locate oil or design a killer perfume. Who says chemistry isn't cool?
That's one seriously big number, and technically Amedeo Avogadro didn't even come up with it. So how did the Italian chemist make such an indelible (numerical) mark on the wonderful world of chemistry?