Unit 2: “Earth and Space Science” Chapter 6 “Weather”

insolation the solar energy that reaches a planet

atmosphere All of the gases that surround the earth

troposphere The layer of the atmosphere closest to Earth’s surface

weather The condition of the atmosphere at a particular time and place

Air pressure The force put on a given area by the weight of the air above it

humidity The amount of water vapor in the air

hygrometer A tool used to measure the relative humidity

Relative humidity measures the amount of water vapor in the air compared to the total amount the air could hold at that temperature

barometer A tool that is used to measure air pressure

Lesson 1 summary How does the sun warm the earth? The solar energy (insolation) that reaches the earth does not warm all places on Earth equally. One reason for the unequal warming is the earth’s shape being a sphere. Sunlight strikes with the most direct angle at or near the equator. Areas that are farther north or south of the equator receive less of the sun’s heat energy. Video link https://www.youtube.com/watch?v=2vEIWTjf4z8

Lesson 1 summary continued… what are the layers of the atmosphere? The layers of the atmosphere begin with the troposphere which is the layer closest to the earth followed by the stratosphere, mesosphere, thermosphere, and exosphere. The troposphere is where most all weather takes place. Factors that affect weather include, but are not limited to, temperature, wind, and cloud cover. Video link https://www.youtube.com/watch?v=5sg9sCOXFIk

Lesson 1 summary continued… What changes air pressure? Some variables (things that can change) that affect air pressure are volume, temperature, altitude, and humidity. Volume is a measure of how much space an object takes up. The more space, the more air, the more air pressure. The warmer the air temperature the more the air particles spread. This causes air pressure to be lower. Altitude is the height above earth’s surface. Air above a mountain has less pressure than air closer to the earth’s surface. Water vapor in the air (humidity) exerts less pressure than dry air. Video link https://www.youtube.com/watch?v=fK_1E9yn-wM

Lesson 1 summary continued… how do we measure air pressure? Air pressure is measure using either a mercury barometer or an aneroid barometer. Video link https://www.youtube.com/watch?v=i2UKTpIQG6M

global wind wind that blows steadily over long distances in a predictable direction

sea breeze the movement of air from the water to the land

land breeze the movement of air from the land to the water

anemometer a tool that measures wind speed

Lesson 2 summary what is wind? Air moves from areas of high pressure to areas of low pressure causing wind. Global winds blow because sunlight heats areas near Earth’s equator more than it heats areas near Earth’s poles. The Coriolis effect describes the change in direction of something on or above the earth’s surface due to Earth’s rotation. The coriolis effect causes winds to curve. Warm air is less dense than cold air.

Lesson 2 summary continued… What are local winds? A sea breeze moves from over the water to the land. A land breeze moves from over the land to the water. A valley breeze occurs when cool air moves up out of the valleys to replace rising warm air. A mountain breeze occurs when cool air from the mountains flows down into the valley. Land/sea breeze Video link https://www.youtube.com/watch?v=gM0d3fGew-0 Valley/land breeze information link http://www.eschooltoday.com/winds/mountain-and-valley-breeze.html

Lesson 2 summary continued… how is wind measured? A weather vane (Wind vane) is used to measure wind direction. A wind sock is another tool that can be used to measure wind direction. An anemometer is used to measure wind speed. Video link https://www.youtube.com/watch?v=SqbTrbxWT1o

isobar a line on a weather map that connects places that have the same air pressure

air mass a large region of the atmosphere in which the air has similar properties

front the boundary where two air masses meet

weather map a map that shows the weather in a specific area at a specific time

Lesson 3 summary what are highs and lows? Isobars are lines on a weather map that connect all the places that have the same air pressure. Isobars that are close together indicate faster wind speeds than those that are farther apart. In a high pressure system, air flows outward from the center in a clockwise direction. In a low pressure system, air flows in toward the center in a counter clockwise direction. Since high pressure air is cool and dry, the weather is usually dry and clear. Since low pressure is warm and humid, the weather is usually warm and stormy.

Lesson 3 summary continued… what are weather fronts? The properties of an air mass depend on the region in which it forms. A front forms where air masses meet. At a cold front, a cold air mass moves in under a warm air mass often bringing brief, heavy storms that are followed by weather that is cooler, clearer, and drier. At a warm front, a warm air mass moves in over a cold air mass bringing light, steady, rain or snow that is followed by weather that is warmer and more humid.

Lesson 3 summary continued… what are weather fronts? An occluded front forms when a wedge of warm air moves between to cold air masses. The result is usually A short storm. A stationary front forms when neither air mass is strong enough to push the other front out of the way. The jet stream is a high altitude global wind which blows from west to east. The jet stream can move a stationary front. Video link https://www.youtube.com/watch?v=CEoehdggywM

Lesson 3 summary continued… what do weather maps tell us? Weather maps show us the weather in a specific area at a specific time. Symbols on a weather map represent variables that can cause weather changes. Variables can be but are not limited to temperature, wind, cloud cover and the location and movement of fronts. Meteorologists are scientists that study these weather variable in order to make forecasts, or predictions, about what weather will occur. Link https://weather.weatherbug.com