Chapter 2 – Weather Patterns

Guided Notes

Objective(s): 7.E.1.4

Predict weather conditions and patterns based on information obtained from:

• Weather data collected from direct observations and measurement (wind speed and direction, air temperature, humidity and air pressure) • Weather maps, satellites and radar • Cloud shapes and types and associated elevation

7.E.1.5 Explain the influence of convection, global winds

and the jet stream on weather and climatic conditions.

• Learner Objective(s): Students will understand that the water cycle and atmospheric conditions are interconnected and create the weather we see on Earth.

Concept/Vocabulary Word Definition

• Deposition - The process of water vapor changing from a gas directly into a solid.

• Dew Point - The temperature at which water vapor will start to condense out of the air as liquid water.

• Evaporation - The process of a liquid changing into a gas

• Fog - Clouds that form at the surface of the Earth.

• Ground Water - Water that has infiltrated (sunk) into the ground.

• Hydrosphere - All of the Earth's water that is cycling within the water cycle.

• Meteorologist - A scientist who studies the atmosphere, weather and climate

• Precipitation - Any type of liquid or solid water that falls to Earth's surface.

• Run Off - Water that flows across the surface of the Earth.

• Sublimation - The process of water changing from a solid directly into a gas.

• Transpiration - The process of water evaporating from the leaves of plants during photosynthesis.

• Water Cycle - The repeating processes that move water in different forms between Earth's surface and the atmosphere

• Water vapor - Water in the atmosphere that is in the form of a gas.

• Weather - The condition of Earth's atmosphere at a particular time and place

• Weather patterns - Weather that repeats itself in a predictable way.

I. SECTION 2.1 – The atmosphere’s air pressure changes A. Air exerts pressure

• Exploring air pressure – What does air do to the egg?

http://www.youtube.com/watch?v=2VHneRg0mhI&list=PLMWvLl-qJ8maQ15p1kZBooG1L1AoFCz6_&feature=plcp

• Air pushes or exerts a force

• Air pressure – is the force of air molecules pushing on an area

• As you move upward in the atmosphere, air pressure decreases

• The greater the force, the higher the air pressure

• Air pressure pushes in all directions

B. Pressure and Air motion

• Air pressure decreases as you move to higher altitude

• Air moves from areas of higher pressure to areas of lower pressure

C. Barometers and Air Pressure Barometer – is any instrument that measures air pressure

III. SECTION 2.2. – The atmosphere has wind patterns • Wind blows from areas of high

pressure toward areas of low pressure. Earth's rotation causes long distance winds to curve.

area of

high

pressure

area of

low pressure

A. Uneven heating causes air to move

• Weather – is the condition of Earth’s atmosphere at a particular time and place

• Wind – is air that moves horizontally, or parallel to the ground

• Uneven heating causes pressure differences which set air in motion

• Over a short distance, wind moves directly from higher pressure toward lower pressure

• Global winds - travel thousands of kilometers in steady patterns and last for weeks

• Uneven heating between the equator and the north and south poles cause global winds

B. Earth’s rotation affects wind direction

• Coriolis effect – influence on Earth’s rotation

• Global winds curve as Earth turns beneath them

• In the Northern Hemisphere, winds curve to the right in the direction of motion

• In the Southern Hemisphere, winds curve to the left in the direction of motion

• The Coriolis effect is noticeable only for winds that travel long distances

http://www.youtube.com/watch?v=uBqohRu2RRk&list=PLMWvLl-qJ8maUvrKjCzRx27pJ9NnKCcWG&feature=mh_lolz

• Investigate: How does Earth’s rotation affect wind?

C. Bands of calm air separate global wind belts

• Calm regions – doldrums and horse latitudes

– Doldrums – are a low-pressure zone near the equator

– Horse latitudes – are high-pressure zones located about 30 degrees north and 30 degrees south of the equator

• Wind belts – trade winds, westerlies, and easterlies

– Trade winds – blow from east, moving from the horse latitudes toward the equator

– Westerlies – blow from the west, moving from the horse latitudes toward the equator. They bring storms across much of the United States

– Easterlies – blow from the east, moving from the polar regions toward the mid-latitudes. Stormy weather often occurs when the cold air of the easterlies meet the warmer air of the westerlies

http://www.youtube.com/watch?v=I0C4QR0OEH0&list=PLMWvLl-qJ8mY36sh_gV7Ume-7kIPbtYIF&index=1&feature=plpp_video

D. Jet streams flow near the top of the troposphere

• Jet Streams – usually flow in the upper troposphere from west to east for thousands of kilometers

• Air often moves at speeds greater than 200 km/hr or 124 mph

• Forms when earth’s surface is heated unevenly

• Loop north and south

• Each hemisphere usually has two jet streams

E. Patterns of heating and cooling cause local winds and monsoons

• Local winds – sea breezes and land breezes

– Occur near shorelines

Valley breezes

• Monsoons – winds that change directions with the seasons

– Caused by the different heating and cooling rates of land and sea