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Why is Brownian motion important to the study of Physics and what are at least 2 examples of Brownian motion in real life situations and the importance of them?


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May 09, 2009 11:14AM

Brownian motion explains, for example, how a liquid's particles move about in a quick trajectory even if it appears to be calm. A great example I found, was imagine quick moving golf balls zooming around a pool table filled with ball bearings. Because of the mass of ball bearings, you don't technically notice the golf balls hidden within, even though they are zooming around. In a solid, the particles vibrate against each other quickly when full of energy. In a liquid, they move around in their container bumping around against each other. In a gas, they speed all over the place until they hit another one. So, back to my point, another example of Brownian motion is, have you ever wondered why if the water is cold, it isn't frozen, because if its cold doesn't that mean there is no energy, so it should be solid? Heat is formed when two particles or more collide. Energy just makes them move. In science classes, the teachers unfortunately usually make it sound like heat is solely the cause of a change in the state of matter. That is not true. If energy could be directly pumped into a particle, it would still move even if no heat was involved. If a particle could somehow move around and never hit another one, no heat would ever be formed. But you need energy in the first place for them to move. Heat is just the easiest way of making energy. It's pretty confusing, I know, and it probably ends up sounding just like the way teachers do it. As a quick revision, if a liquid is cold, that does NOT mean it is a solid. Think of this, a room floor with two dozen golf balls zooming around but they never hit each other often enough for noticeable heat to be formed. If water is luke warm, they are hitting kind of often, if it's freezing, they probably only hit each other once in a while, if it is boiling, they probably just can't stop colliding. Brownian motion explains all of this.