Why must a scientist use standard units of measure in experience and work

Standard units are commonly used units of measurement, which help us measure length, height, weight, temperature, mass and more. These units are standardized, which means that everyone gets the same understanding of the size, weight and other properties of objects and things.

their crystal patterns have been disrupted by stress

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me