As heat is taken away from a fluid, its particles. slow down and come closer together. ï®. This causes the fluid to contract â its volume. decreases. ï®. This causes the density to increase. (D=M/V if V gets smaller, M/V gets bigger) ï®. Viscosity will also be affected, as particles slow. down and come closer together, it gets harder. for them to move past each other. Therefore, viscosity increases.
The commercial kind are probably $250 on up. You can get a nice Shure brothers mike for around $120. Their SM-58 is good for recording and amplifying voices, and the SM-57 excels at recording or amping musical instruments. Sennheiser is a long-time company that also makes several lines of mikes (or mics, if you prefer) that range from home-use to phenomenal studio use.
In 1878, the carbon microphone was invented by David Edward Hughes, and later developed during the 1920s. Hughes's microphone was the early model for the various carbon microphones now in use. With the invention of the radio, new broadcasting microphones were created. The ribbon microphone was invented in 1942 for radio broadcasting. In 1964, Bell Laboratories researchers James West and Gerhard Sessler received patent no. 3,118,022 for the electroacoustic transducer, an electret microphone.