Weather Our World: What is Weather? video What do you think of when someone says weather?
Questions from Bill Nye video 1. What causes wind? 2. What are two things that were mentioned by Bill Nye that causes wind? 3. True or False. Cold air pushes up warm air.
Weather is the state of the atmosphere at a specific time and place. What drives Earth s weather?
Includes such conditions as air pressure, wind, temperature and moisture in the air.
The Sun s heat evaporates water into the atmosphere forming clouds; water returns to Earth as rain or snow; the Sun also heats air.
Temperature is a measure of air molecule movement.
What do you think??? 1. When the temperature is high, how do the molecules in the air move? Do you think it would feel warm or cold? 2. When the temperature is low, how do the molecules in the air move? Do you think it would feel warm or cold?
The Sun s energy causes air molecules to move rapidly; temperatures are high and it feels warm
When less of the Sun s energy reaches air molecules, they move less rapidly and it feels cold.
Quiz 1. State of the atmosphere at a specific time and place, determined by factors Including air pressure, amount of moisture in the air, temperature, wind, and Precipitation is called. 2. What drives the Earth s weather? 3. What causes wind? 4. A measure of air molecule movement is called. 5. If air molecules are moving rapidly, would you feel warm or cold? 6. If air molecules are moving slowly, would you feel warm or cold?
Wind air moving in a specific direction. Why can you fly a kite on some days but not others?
Many instruments can be used to measure wind direction and speed. Wind Vanewind direction Wind Sock-wind direction Anemometer-wind speed
As the Sun heats air, it expands, becomes less dense, rises, and has low atmospheric pressure.
Cooler air is denser and sinks, causing high atmospheric pressure.
Air moves from high pressure areas to low pressure areas, causing wind. What do you think iso means? Use your textbook to look up the word isobar.
Humidity the amount of water vapor in the air.
Warmer air can hold more water vapor, tending to make it more humid.
Relative humidity the amount of water vapor in the air compared to what it can hold at a specific temperature.
When air cools, it can t hold as much water vapor, so the water vapor condenses to a liquid or forms ice crystals.
Dew point- the temperature at which air is saturated and condensation forms.
Quiz 1. What is the state of the atmosphere at a specific time and place? 2. What is a measure of air molecule movement? 3. Air moving in a specific direction is called. 4. Warm, expanding air has (high/low) pressure. 5. Cold, sinking air has (high/low) pressure. 6. Instrument used to determine wind direction is called a. 7. Wind speed is measured using an. 8. Air moves from pressure areas to pressure areas. 9. is the amount of water vapor in the air. 10. The temperature at which air is saturated and condensation forms is called the.
Clouds form as warm air is forced upward and cools. then the water vapor condenses in tiny droplets that remain suspended in the air. Cloud Video
The shape and height of clouds vary with temperature, pressure and the water vapor in the atmosphere.
In 1803, Luke Howard classified clouds using Latin terms cirrus, cumulus, stratus, And nimbus. Now using a dictionary, look up the following words: 1.Cirrus 2.Cumulus 3.Stratus 4.Nimbus
Cloud Shape Stratus: smooth, even sheets or layers at low altitudes.
Cloud Shape Cumulus: puffy, white clouds, often with flat bases.
Cloud Shape Cirrus: high, thin, white feathery clouds made of ice crystals.
Cloud Height Cirro: high clouds Alto: middle-elevation clouds Strato: low clouds
Nimbus clouds are dark and so full of water that sunlight can t penetrate them.
Clouds Stratus Clouds-Very little precipitation from most stratus clouds -Two types of stratus clouds: Nimbostratus (heavy precipitation) Altostratus (very little precipitation) Cumulus Clouds- Associated with fair weather or thunderstorms -cumulonimbus clouds or thunderheads are accompanied by rain, lighting & thunder Cirrus Clouds-associated with fair weather but they can indicate approaching storms. -Cirrocumulus clouds appear just before snowfall or rainfall
Precipitation: water falling from clouds.
When water droplets in clouds combine and grow large enough precipitation falls to Earth.
Air temperature determines whether droplets form rain, snow, sleet, or hail.
Now do the Section 1 Review Questions found in your textbook on page 574. Do questions #1, 2, 3, 4, 5, and 6
Section 2: Weather Patterns Mr. Parr wind song review
Because air and moisture move in the atmosphere, weather constantly changes.
Air mass large body of air with properties like the part of Earth s surface over which it is formed.
Highs and Lows Stormy weather is associated with low pressure areas.
Fair weather is associated with high pressure areas.
Air pressure is measured by a barometer.
Front a boundary between two different air masses.
Clouds, precipitation, and storms occur at frontal boundaries.
Cold front- where colder air advances under warm air.
Warm front where warmer air advances over colder air
Occluded front involves three air masses of different temperatures.
Stationary front air mass and their boundaries stop advancing. Warm, moist air is forced rapidly upward, where it cools and condenses. Strong updrafts of warm air and sinking, raincooled air cause strong winds. Mr. Parr Front song
Thunderstorms occur inside warm, moist air masses and fronts. Tornado footage Weather 101
Lightning Movement of air inside a storm cloud causes parts of the cloud to become oppositely charged. Current flows between the regions of opposite electrical charge, forming a lighting bolt. How lightning Forms? How lightning Works discovery Channel 5 min
Thunder lighting superheats the air, causing it to expand rapidly and then contract, forming sound waves.
Tornado a violent, whirling wind that moves in a narrow path over land. How Tornado form
Hurricane a large, swirling, lowpressure system that forms over How Hurricanes work tropical oceans.
Blizzard a winter snow storm with strong winds, cold temperatures, and low visibility, that lasts more than three hours.
Severe Weather Safety A National Weather Service watch means conditions are favorable for severe weather to develop. A warning means that severe weather conditions already exist.
Section 3: Weather Forecasts
Meteorologists study and predict the weather.
The National Weather Service makes weather maps.
Station models show weather conditions at a specific location.
Temperature and Pressure Isotherms are lines on a weather map connecting points of equal temperature. Isobars are lines on a weather map that connect points of equal atmospheric pressure.
Weather fronts move from west to east.