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Atmosphere and Air Pressure By: Riya Murdeshwar, and Shaily Desai

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Main Idea Earths atmosphere is a mixture of gases that surrounds the planets. The atmosphere exerts a pressure that decreases with distance above Earths surface.

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Vocabulary Weather The overall condition of the atmosphere at a given time and place. Atmosphere A mixture of gases that surrounds the planet.

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The 4 layers of Earth TT hermosphere MM esosphere SS tratosphere TT roposphere

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The Ozone Layer o Ozone: A form of air that protects living things o Absorbs certain types of radiation from the sun. o Most of our planets ozone is in the Stratosphere.

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Air Pressure o Air Pressure: The force exerted by air on a given area. MEASURING AIR Pressure Air pressure at Earths surface is always changing. To keep track of these changes, scientists use an instrument called a barometer to measure air pressure.

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The 2 Types of Barometers Mercury Barometer CContains a column of mercury in a glass tube. TThe column of mercury rises in the tube when air pressure decreases. Aneroid Barometer HHas a dial connected to a small ceald can than contains no air. WWhen the air pressure decreases, the sides move outward. WWhen the air pressure increases, the sides of the can are pushed in, just as the sides of a rubber ball are pushed in when you squeeze it.

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Pressure Systems Low Pressure These form when air at Earths surface rises and air pressure decreases. Air rises when it moves in towards the center of the system. Northern Hemisphere-air rotates in a counterclockwise direction Southern Hemisphere-air rotates in a clockwise direction High Pressure These form when air pressure increases The air moves out from the center of the highest pressure Northern Hemisphere-system rotates in a clockwise direction Southern Hemisphere-system rotates in a counterclockwise direction Air pressure on Earths surface is always changing.

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Uneven Heating SSun heats Earths surface unevenly EEarth rotates on its axis causing day and night TThe Sun rays strikes at different angles (The daytime side of the Earth is warmer than the nighttime side) PPolar regions receive the same amount of energy as places near the equator TThe tilt of the axis affects the heating of Earths surface UUneven heating also occurs because different materials heat up and cool down at different rates. (The ocean heats up and cools down slower than land does) CCities tend to be warmer than surrounding rural areas

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Global Pressure Belts Local high-pressure and low-pressure systems affect weather all across the globe. Air becomes less dense when it is warmed and more dense when it is cooled. Uneven heating also create global belts of high- pressure and low-pressure.

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Types of Global Pressure Belts Low-Pressure Belts How does it form? 1. Earths surface near the equator is intensely heated by the sun 2. the warm air above the surface rises 3.its pressure decreases 4.The rising air forms a low-pressure system near the equator. High-Low-Pressure Belts Air near the poles receive the least amount of heat from the Sun so when air sinks and cools it forms a high-pressure belt. Two belts of high pressure form near 30 degrees north and south latitude.

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Air Pressure Associated With Weather Unsettled Weather and Low Pressure Systems 1.Air is heated by the surface 2.Below it, air becomes lighter or less dense than the surrounding air 3.The lighter air is forced up 4.As it rises, it cools 5.Clouds may form (which can often lead to rainy or even stormy weather) So low pressure systems are associated with unsettled weather. Fair Weather and High Pressure Systems 1.Air is cooled 2.It becomes heavier or denser than the surrounding area 3.The dense air sinks or settles towards the surface 4.The sky remains clear (Clouds cannot form under these conditions) So high pressure systems are generally associated with fair weather.

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Weather o Weather forecasters track pressure systems o Air pressure is just one of the factors that affects weather o Other factors include: 1.Humidity 2.Wind speed 3.Direction 4.Temperature 5.Air Pressure

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Beyond the Book

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The Exosphere Exosphere is a Greek word that means outside (or external) sphere. The top of the exosphere is generally marked at 6,200 miles above sea level. Put another way, that is the same distance as a round trip from Boston to San Francisco. Some scientists actually consider the exosphere as part of outer space, as there is such a gradual and fuzzy distinction between the density of molecules in the very upper reaches of the atmosphere and lower reaches of space.

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More facts about the Exosphere It is in the exosphere that satellites orbit; in this environment, there is very little friction as compared to lower levels of the atmosphere, meaning it is the perfect place for equipment such as satellites to orbit with minimal disruption from molecular interference. In the most technical sense, the upper limit of the exosphere is the last point at which Earths gravity still has any influence on particles. Using this definition, the upper exospheric boundary could be as high as 120,000 miles. Because the air in the exosphere is extremely thin, temperatures range quite drastically. Generally, the exosphere on the daytime side of the Earth can exceed 1,000 degrees, while things are far cooler on the nighttime side only a few degrees above absolute 0.

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Types of tools and their uses

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Rain Gauge Anemometer Measures the amount of precipitation o Measures wind speed

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Thermometer Radar Measures temperature in Celsius and Fahrenheit Measures the strength of storms

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Wind Vane Balloon Measures the winds direction Measures the conditions in the upper atmosphere

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Just Kidding!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Just Kidding!! This is a real picture of a balloon.

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Satellite Measures the cloud, land, and ocean conditions In - Orbit Satellite Ground Satelllte

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Pop Quiz A.What is the definition of Weather? 1.The overall condition on Earths surface 2.The overall condition of Earths atmosphere 3.The overall condition of Earths atmosphere at a given time and place 4.The overall condition of Earths four layers B.What are the four layers of Earths atmosphere? 1.Troposphere, Mesosphere, Stratosphere, and Thermosphere 2.Troposphere Ice-creamosphere, Mesosphere, and Thermosphere 3.Circlesphere, Mesosphere, Stratosphere. and Thermosphere 4.Sattelites, Radar, Troposphere, and Mesosphere

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1What does a barometer measure? a.Measures air pressure b.Measures air mass c.Measures the amount of precipitation d.Measures air temperature in Celsius and Fahrenheit 2What does a rain gauge measure? a.Measures the amount of ice-cream scoops b.Measures the amount of precipitation c.Measures air temperature in Celsius and Fahrenheit d.Measures how strong a storm is

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Pop Quiz 1What does Anemometer measure? a.Measures air condition b.Measures air mass c.Counts how many donkeys live in America d.Measures air temperature 2What does a wind vane measure? a.Measures the how many cheese sticks are in 1 package b.Measures the amount of precipitation c. Measures the winds direction d.Measures how strong a storm is

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We appreciate your attention and hope you enjoyed our presentation. Furthermore, we hope you learned something through the experience of atmosphere and Air Pressure. We are glad to give you more edumacation and provide you with additional brain knowledge.