# Temperature and the kinetic energy of everything

• DLeuPel
In summary: In these experiments, the molecules have a temperature of 0K.Interesting to speculate how this picture might change at relativistic velocities.
DLeuPel
Earth rotates, it also orbits the Sun, the Sun orbits the galaxies and these have they’re own velocities as well. We know that the kinetic energy is measured by its velocity, and also that kinetic energy is related with temperature. By this I mean that the movement of particles are a measure of they’re temperature, meaning that if you were to make they’re movement faster, you would then increase they’re temperature. But these particles have already a velocity and a kinetic energy, even tho they look stationary to us.

It might be possible that that high amount of energy , we cannot notice it because we have are under the same effect as say a box of liquid water. Now my question comes here, if I where to have velocity 0 with respect to the rotation of Earth, would that box of water molecules be hot if I happen to touch it for an instance ( let’s say that the top part is open in a way that I can put my hand without effort since it is at an instant ). This can be achieved if I where to impulse myself in the contrary direction of the Earth’s rotation and having the exact same speed as the orbit but with contrary directions of the velocity. I guess it would also mean that air is hot as I touch it as well.

DLeuPel said:
and also that kinetic energy is related with temperature
Only unordered kinetic energy is linked to temperature. A combined motion of the whole object does not.
DLeuPel said:
meaning that if you were to make they’re movement faster, you would then increase they’re temperature
Not necessarily.
DLeuPel said:
if I where to have velocity 0 with respect to the rotation of Earth, would that box of water molecules be hot if I happen to touch it for an instance
No. If you move fast relative to the water your hand would experience a lot of drag from the water, however, and friction would heat up the contact area quickly.
DLeuPel said:
This can be achieved if I where to impulse myself in the contrary direction of the Earth’s rotation and having the exact same speed as the orbit but with contrary directions of the velocity.
I'm not sure what you mean here.

mfb said:
I'm not sure what you mean here.
Instead of orbit, I should have written rotation. By this I mean that you don't rotate with the Earth anymore.
Also, a waterfall has a lower temperature at its top than at its bottom. Shouldn’t this mean that a gain in kinetic energy that is not random kinetic energy increases temperature ?

The water gets warmer when it is stopped at the bottom and the kinetic energy from the falling water is converted to thermal energy. Directly before hitting the bottom it is not warmer (it actually tends to be a bit cooler from evaporation, but that is a different topic).

davenn, DrClaude and russ_watters
I once read that it is not the velocity of particles that determines temperature, but the width of the velocity distribution. Thus a bunch of atoms all moving as a cluster in perfect sync would have a temperature of 0K. I suspect this is how they use lasers to create Bose-Einstein condensates with temperatures close to absolute zero.

Interesting to speculate how this picture might change at relativistic velocities.

Rob Lewis said:
I once read that it is not the velocity of particles that determines temperature, but the width of the velocity distribution. Thus a bunch of atoms all moving as a cluster in perfect sync would have a temperature of 0K. I suspect this is how they use lasers to create Bose-Einstein condensates with temperatures close to absolute zero.
No. In BEC, the actual velocity of the atoms is extremely low. It is not just a question of the width of the velocity distribution.

There are experiments where molecules are cooled to very low temperatures in the sense of the width of the velocity distribution, but where they are trapped in a circular ring (a bit like in a particle accelerator) such that the molecules are still going fast with respect to the lab, but not with respect to each other.

## 1. What is temperature?

Temperature is a measure of the average kinetic energy of the particles in a substance. It is a way to quantify how fast the particles are moving.

## 2. How does temperature affect the kinetic energy of everything?

As temperature increases, the kinetic energy of particles also increases. This is because higher temperatures mean that the particles are moving faster and have more energy.

## 3. Is there a relationship between temperature and the speed of particles?

Yes, there is a direct relationship between temperature and the speed of particles. As temperature increases, the speed of particles also increases.

## 4. How does temperature affect different types of matter?

Temperature affects different types of matter in different ways. For example, temperature has a greater impact on the kinetic energy of gases compared to solids, as gases have more room to move and therefore can reach higher speeds at higher temperatures.

## 5. Can temperature be measured accurately?

Yes, temperature can be measured accurately using thermometers or other temperature measuring devices. However, it is important to use the correct units and calibration to ensure accurate measurements.

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