Download WEATHER UNIT STUDY GUIDE Weather

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WEATHER UNIT STUDY GUIDE
Weather- the current state of the atmosphere. It includes variables such as temperature, wind
direction, wind speed, air pressure, precipitation, humidity, cloud cover, dew point.
Temperature is measured using a thermometer.
Air Pressure is measured using a barometer. High air pressure signifies good weather.
Wind speed is measured by an anemometer.
Climate- describes weather patterns over a long period of time. There are 6 climates according to the
Koppen classification system. They are polar, (North and South Poles), severe, mild, highland
(mountains), dry, (desert) and tropical (warm with a lot of precipitation). Connecticut’s climate is
severe. Some factors that can affect climate are, ocean currents, latitude (distance from the equator),
distance from an ocean, and prevailing wind direction.
The Earth’s atmosphere is made up of 78% Nitrogen, 21% Oxygen, and 1% trace gases. Air pressure is
greatest in the troposphere because all the gases are above you and air pressure is lower as you go up in
the atmosphere.
Exosphere is the top layer and merges into outer space. Satellites orbit here.
Thermosphere is the hottest layer. Temperature increases with altitude.
Mesosphere protects us from meteors and temperature decreases with altitude.
Stratosphere contains the ozone layer which protects us from harmful ultraviolet
radiation. Temperature increases with altitude.
Troposphere is where we live and all weather occurs.
Water is found on Earth in all three phases: solid, liquid, and gas. Freezing occurs when a liquid changes
phase into a solid. The temperature at which fresh water freezes is 32 degrees Fahrenheit or 0 degrees
Celsius. The process of changing a solid into a liquid is called melting.
The water cycle is powered by the energy from the sun. This energy turns liquid water from surface
water sources such as oceans, lakes, rivers, and streams, into a gas called water vapor. This process is
called evaporation. Water vapor is less dense so it rises through the troposphere and is cooled as it
rises. It changes phases from a gas to a liquid (water droplets) and forms clouds. This process is called
condensation. These clouds bring precipitation and the type of precipitation that will fall is determined
by the air temperature. The water will run off surfaces and find its way back to water sources for the
cycle to continue. Water that collects in rocks and soil underneath the Earth’s surface is groundwater.
Convection Currents describe how heat moves through a liquid or gas. Hot air rising and cool air sinking
are examples of convection currents. This can occur in our atmosphere due to uneven heating of the
Earth’s surfaces and causes high and low pressures and wind. This also occurs in liquids. Ocean
currents affect climates by transferring heat from one part of the world to another. The Gulf Stream
brings warm water up the Atlantic Coast toward Europe. For example, the climate of Ireland is warmer
than it should be at that latitude due to the Gulf Stream. Warm surface currents heat and moisten the
air above them and cold ocean currents, such as the California Current, cool the air above them and
create a cooler climate.
Wind is air that is moving from high pressure areas to low pressure areas. The greater the difference in
air pressure, the higher the wind speed will be. A sea breeze is a wind that comes from the sea because
there is higher pressure over the water during the day. A land breeze is wind that comes from the land
because the air pressure is higher over the land at night. The wind direction always describes the
direction the wind is coming from.