Masses

1. Masses

2. Air Pressure • Air pressure is the force of air, exerted on the objects on Earth’s surface • We are being pushed from every direction • Pressure is measured by a tool that we call a barometer • Pressure, or changes in air pressures are what give us winds

3. Air Pressure • Air movement (wind) moves from areas of high pressure to areas of low pressure • The Corioliseffect, the rotation of Earth that causes the ocean currents to deflect, will also cause the wind to deflect as well • Northern Hemisphere → Right • Southern Hemisphere → Left • Wind speed is measured by an instrument known as a aneometer

4. Pressure Centers • Pressure Centers are areas where concentrated pressure will affect the weather in a given area. • There are two types of Pressure Centers 1. High Pressure Centers (Cyclones) • Pressure will be highest on the inside and lowest on the outside • Winds will blow clockwise and outwards from the centers • accompanied by fair weather and sunny skies

5. Pressure Centers 2. Low Pressure Centers (Anti-cyclones) • Pressure will be highest on the outside and lowest on the inside • Winds will blow counterclockwise and outwards towards the center of a center. • Accompanied with poor weather and rain

6. Pressure Map • Isobars or lines of equal pressure are shown on the map • When isobars are close together, the winds will have a higher velocity • When isobars are far apart or spread out, the winds will have a lower velocity