1 / 9

The atmosphere’s air pressure changes.

The atmosphere’s air pressure changes. Air exerts pressure. Air molecules are moving constantly. As they move they are constantly bouncing off other air molecules and surfaces. Each time it bounces on an object, it pushes or exerts force on that object.

mahon
Download Presentation

The atmosphere’s air pressure changes.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The atmosphere’s air pressure changes.

  2. Air exerts pressure. • Air molecules are moving constantly. As they move they are constantly bouncing off other air molecules and surfaces. • Each time it bounces on an object, it pushes or exerts force on that object. • Air pressure – the force of air molecules pushing on an area; the greater the force, the higher the air pressure • The air is being pushed in all directions

  3. Differences in air pressure Low Pressure • When air rises, it leaves behind an area of lower pressure, because the upward- moving air is not pressing down so hard on the surface.

  4. High Pressure • Areas of high pressure are formed where air is sinking back down, and so pushing down harder. • >> see the diagram

  5. Changes in air pressure cause changes in the weather. • Pressure is different all over the world. • Lows are areas of low pressure with the lowest pressure at the center. • Lows usually bring wet, cloudy weather.

  6. Highs are areas of high pressure with the highest pressure at the center. • Highs bring sunnier, and dry weather. • The way these move from day to day causes the changes in the weather.

  7. Air pressure is related to altitude and density. • When you hold your hand out by your side, the force of air pressing down on your hand is greater than the weight of a bowling ball. However, we do not feel this force because the same amount of force is pushing up on our hand because air moves in all directions. • Air pressure decreases as you move higher in the atmosphere because you have less air above you. • Air pressure is greater at sea level than it is on top of a mountain. The air is more dense because the air molecules are pushed closer together since there is more pressure. • Air pressure increases as density decreases.

  8. Pressure and Air Motion • Air pressure can vary at two different locations at the same altitude. For example, when you open a new can of tennis balls you might hear a hissing sound. This is because there is lower air pressure inside the can, and as soon as the can opens, the air around the can moves into the lower pressure areas. • If air pressure was the same around the Earth, the atmosphere wouldn’t move much. Because there are differences in pressures, air is constantly moving. High pressure areas are moving towards low pressure areas.

  9. Barometers and Air Pressure • Barometer – an instrument that measures air pressure • In some cases, there are instruments that have a chamber to measure the air pressure. When the pressure is high, the chamber contracts. When the pressure is low, the chamber expands. Depending on how much it contracts or expands, a needle will point to a certain air pressure.

More Related