|
|
This post is about pressure in a gas. It is not about liquid pressure; the particles in a liquid are already touching, and the collisions are minimal.
 Originally Posted by OngBonga
I always assumed pressure was the collective weight of what's above you, so water pressure is the weight of all the water directly above you, plus 1 atmosphere of air pressure.
Pressure is not weight. Pressure is force applied over an area. Weight is a force.[/nitpicking]
As far as the pressure you experience while walking around and swimming, that's right.
If you were in a sealed chamber, though, the pressure can be anything, regardless of the pressure outside the chamber. So long as the chamber is constructed to withstand the pressure differential.
Originally Posted by OngBonga
If it's particle density, well that explains why pressure increases with temperature, and it explains atmpospheric pressure because gas is compressible.
I think you've gone off track a bit here.
Pressure increases with temperature because temperature is a way of talking about the vibrations of particles. Ultimately, temperature is just a measure of kinetic energy. When temperature increases, the particles vibrate more vigorously. When the more vigorously vibrating particles bounce off of each other, they impart more energy to each other, and increase the average velocity of the particles. This increased velocity means that the collisions are more forceful.
The increase in pressure associated with temperature increase is due to higher average particle speeds. The higher speed particles bounce off of the walls of their vessel with greater force because they're moving faster. This increased force per bounce results in greater pressure.
Originally Posted by OngBonga
If pressure has no effect on the density of a liquid, then how does particle density increase? That's why I'm confused, because I agree with what you said renton and that doesn't tally with the idea that pressure is simply a measure of particle density.
Pressure is a relationship between number of particles, the volume in which they are contained, and the temperature of those particles.
This is because a consequence of increased temperature is increased average particle speed.
When the particle density goes up, the pressure goes up because there are more particles bouncing around.
When the temperature goes up, the pressure goes up because the particles are bouncing harder.
|
Reply With Quote