what is the difference between a high pressure and a low pressure?

Question

Is high pressure when it is cold and low pressure when it is hot or the other way around? This has been bugging me for years!

Answer 1

Remember:
Increasing the temperature, increases the molecular motion.
Increasing the molecular motion, increases the volume.
Increasing the volume, decreases the density of the molecules.
Therefore, Increasing the temperature, causes a decrease in the density.


Applied to air masses, this means that heating an air mass causes it to be less dense or somewhat 'lighter' in comparison to the 'cool' air masses.

Warmer Temperatures = Lower Air Pressure
Colder Temperatures = Higher Air Pressure
http://www.angelfire.com/ny2/calmaya/wind.html

Answer 2

High pressure/low pressure really don't have anything to do with temperature. High pressure is when the air sinks, creating greater pressure down here on the ground. Since the air cannot rise, clouds generally cannot form. That is why it is generally sunny. Low pressure is just the opposite and is usually stormy. Now you can have an artic high pressure that comes from the north that will be very cold and you can have a tropical low pressure that will be very warm. That is why temperature is usualy not a determinate of high and low pressures.

Answer 3

When the barometric pressure drops it is usually going to rain, meaning also cooler. When the pressure rises, it indicates warmer fair weather.

Remember that PV =nRT
P Pressure
V Volume
n moles (and you can disregard this in this case)
R Universal gas constant
T temperature
So when temp rises, pressure rises, and vise-versa, but the high pressure will move towards areas of low pressure to try and reach equilibrium (one of the reasons for air currents), so ultimately temps and pressure aren't as directly related in this model as they would be in a completely closed system. So if you want to use the barometric pressure as an indicator just re-read my first 3 lines.

Answer 4

Pressure of a gas depends on both volume and temperature. If you keep volume fixed and increase the temperature, pressure will increase. If you lower the temperature, pressure will decrease. Not sure what specific situation you are referring to, but this is how the Ideal Gas Laws work.

If you are talking about atmospheric pressures, i suppose you could also say that higher temperature makes the air less dense and thus making it seem like a lower pressure, and lower temperature makes it more dense thus making us see it as higher pressure.

Answer 5

low and high pressure is not influenced by temp. being in high pressure is a sign of good weather no matter if it is summer or winter. low pressure makes it easier for thunderstorms to develop in the summer and winter stroms in the winter. the pressure always drop when stormy/snowy weather is moving in.

an area of lower atmospheric pressure(low pressure) make it easier for mosture and heat to rise and form clouds. if enough clouds and moisture rise then you get storms. if this same senerio happpens over warm oceans , you get a tropical low,and it keeps advancing to tropical wave, depression, storm, and then hurricane, on the other hand high atmospheric pressure pushes down on the moisture and keeps heat trapped on the ground, so a high pressure does trap heat but it doesnt create it. and a low pressure doesnt make it cold it just let out the trapped heat. high pressure is sometimes refered to as a "cap" because it holds down heat and moisture.

Answer 6

Surface temperature differences cause vertical wind currents. A hot surface heats the air above it, and the air expands and rises, lowering the air pressure and drawing colder air into its place. Rising and expanding air gives up its heat and so cools, which causes it to shrink and sink, increasing air pressure and displacing the air already below it.

Answer 7

High pressure is ussually the amount of something like alot of air in alittle place.Soon it will burst out.Low pressure is just not much of it.

Answer 8

its_ok_im_here69 got it inverted, the higher density causes more friction which makes heat, less density causes less friction allowing for cooler temperatures.

High density=high pressure, low density=low pressure.

Answer 9

The temperature of the air mass.

Answer 10

ones high and ones low