Mechanical motion VS thermal motion

In summary: But we can't see it or measure it because it's virtual.In summary, zero-point energy is the energy of empty space. It doesn't affect the motion of particles, but it does follow certain statistical trends. And the difference between thermal and mechanical motion is that thermal motion is disordered and random, while mechanical motion is ordered and coherent.
  • #1
KFC
488
4
Hi there,
I wonder if there is anything call mechanical motion(movement)? How does it compare to so called thermal motion? I know in microscopic area, particles are moving randomly due to thermal effect. If we call this thermal (Brownian) motion, so what's the name of motion of macroscopic object moving governed by Newton's law?

By the way, as we know, even we cool the object to 0K, there is still something called zero-point energy. So will particles move with zero-point energy? If so, how do we call this kind of motion (thermal motion is no longer suitable in this case, right?)
 
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  • #2
The difference that comes to my mind is thermal motion is disordered or random, while mechanical motion is ordered or coherent.

Zero point energy, I believe, is not the energy left in a particle that is super cooled - it is the energy of 'empty' space, the vacuum.
 
  • #3
Academic said:
The difference that comes to my mind is thermal motion is disordered or random, while mechanical motion is ordered or coherent.

Zero point energy, I believe, is not the energy left in a particle that is super cooled - it is the energy of 'empty' space, the vacuum.

So you mean the zero-point energy doesn't even affect the motion of particles?

By the way, what about the variational motion among particles? Is it ordered or disordered? Why?
 
  • #4
KFC said:
So you mean the zero-point energy doesn't even affect the motion of particles?

I believe that zero point energy comes from the random motion of quantum particles.

Based on my understanding, quantum particles will continue to move even at 0k. However it is not possible to reach that temperature.
KFC said:
By the way, what about the variational motion among particles? Is it ordered or disordered? Why?

You mean is the motion random? As far as I know, yes. Quantum fluctuations are not ordered, but they do follow certain statistical trends. For example, heat generally does not go from a cold body to a warmer one. (This would require the application of work.)

As to the why... I'd also love to know.
 
  • #5
KFC said:
Hi there,
I wonder if there is anything call mechanical motion(movement)? How does it compare to so called thermal motion? I know in microscopic area, particles are moving randomly due to thermal effect. If we call this thermal (Brownian) motion, so what's the name of motion of macroscopic object moving governed by Newton's law?
There is only one type of motion, namely the one governed by Newton's laws (or quantum mechanics if you want to be more precise).
"Thermal motion" is just molecules flying around like billard balls on the table. You might invent other terms like "circular motion", but fundamentally it's all the same.

KFC said:
By the way, as we know, even we cool the object to 0K, there is still something called zero-point energy. So will particles move with zero-point energy? If so, how do we call this kind of motion (thermal motion is no longer suitable in this case, right?)
0K does not mean the particle have no energy left. It only means all particles are in the lowest energy state. This lowest energy state might still have some energy left.
 

What is the difference between mechanical motion and thermal motion?

Mechanical motion refers to the movement of an object due to applied forces, such as pushing, pulling, or gravity. Thermal motion, on the other hand, is the random movement of particles within a substance due to their kinetic energy.

Which type of motion is more predictable?

Mechanical motion is generally more predictable because it is influenced by external forces that can be measured and controlled. Thermal motion, on the other hand, is influenced by random collisions between particles and is more difficult to predict.

How do mechanical and thermal motion affect each other?

Mechanical motion can cause an increase in thermal motion, as the movement of an object can generate heat. Conversely, thermal motion can also affect mechanical motion by causing changes in the size, shape, or state of an object due to thermal expansion or contraction.

What are some examples of mechanical motion?

Examples of mechanical motion include a car moving down a road, a ball rolling down a hill, or a pendulum swinging back and forth.

What are some examples of thermal motion?

Examples of thermal motion include water boiling in a pot, air molecules vibrating in a room, or the movement of particles in a gas or liquid.

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