Question

What is the concept behind a centrifuge

Answer 1

centrifugal force (as opposed to its opposite centripetal force) simply pushes the heavier solvents within a solution to the bottom of the tube. Simply put, have you ever tied something to a piece of string and spun around with it? Centrifugal force raises the object to a level with the force being acted upon it. I'm not sure I've answered that properly...

Answer 2

As mass increases, resistance to motion (inertia) increases. Thus, as you go round and round, more massive objects will want to travel in a straight line more so than less mass objects. Thus, they will be more likely to be "pushed" towards the bottom of the tube while allowing less massive objects to float on top. There is no force producing this motion as the centrifugal force is technically "fictitious". Observe my drawing to have a better understanding of how this works. Let me know if you have any other questions.

Answer 3

can we say that percieved gravity is the actual reason behind settling down of heavier partlicles?

Answer 4

and why does the heavier partlicles want to move in a straight line more than the lighter particles?

Answer 5

The heavier object is naturally more resistant to motion so it will "want" to take the path of least resistance more so than the lighter object. In this case, the path of least resistant is a straight line. I'm sure that gravity has something to do with it but centrifuges often spin in the horizontal plane, with the test tubes as some small angle from the horizontal, so gravity doesn't have much to do with this. ... if you have questions about this let me know.

Answer 6

i m not speakin about gravity,i m speaking abt 'percieved' gravity and how can we say that the path of least resistant is a straight line?

Answer 7

I've never heard the term perceived gravity. Or perhaps I have, but not often enough and too long ago, and don't remember. If you are referring to the perceived force that objects feel pushing them towards the walls of a spinning object (the bottom of the test tube in this case) that force is called "centrifugal" and it is not a real force. The only real force in a circular motion problem is the centripetal force pushing objects always towards the center of the motion. The equation of that force is: \[f = m(v^{2}\div r)\]

Answer 8

re straight line. I'm not sure why a straight line is the path of least resistance. However, objects always do take the path of least resistance. How could a mass in a test tube know that it is traveling in a circle unless there was a force pushing it in a circle? The centripetal force does not kick in until the mass gets to the lowest part of the test tube. Put another way, the mass will follow a a new path of least resistant (a circle) when it can not longer follow its old path of least resistance (a straight line). Or put yet another way, objects move in the direction of the net force. So, until the mass gets to the lowest part of the spinning test tube, the net force on the object is actually along a straight line. Then, when the object gets to the bottom of the tube, it will feel the bottom of the tube move it in two directions at once (straight and towards the center) and so it will follow the direction of the vector sum of these forces, which over time turns out to be a circle....I'm not sure if I am helping or just confusing the situation.