Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Weather Pressures
Name: Rebecca
Status: Student
Age: 9
Location: N/A
Country: N/A
Date: N/A 

In weather, what does high pressure and low pressure mean?

Hi Rebbecca

You make a high pressure when you squash lots of air into a small space. Imagine you were pumping up a bicycle tire. You can pump a lot of air into a tire - more air than would normally fit into a space the size of a bicycle tire. The air inside the bicycle tire is at a high pressure.

When they talk about high and low pressure in the weather they mean that sometimes the air above a n area of land can get slightly more squashed up than is normal. This is a high air pressure. The reverse can also happen - the air can be slightly more spread out than normal and this is called a low air pressure.

When there is a high pressure in the air above a piece of land there is nothing to stop it spreading out into the air that is at a low pressure. When you get a high pressure bit of air next to a low pressure bit of air the air will move from the high pressure to the low pressure. This movement of air is wind.

Thanks for the question.

Cameron Millsom

Click here to return to the Environmental and Earth Science Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory