Unequal Heating, Air Pressure and Winds power point FACT FINDING!!!!!!

Earth is heated unequally not equally Earth is heated unequally not equally. Different areas of Earth are heated and cooled at different rates. This plays a part in our global winds as well. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates.

Air Pressure Review Air has mass. Air takes up space. Air has density. Air pressure is the weight of a column of air pressing down on an area.

Atmosphere/Pressure Atmosphere held in place by gravity Pressure strongest at surface-more air above you *as altitude increases, air pressure decreases Stack of books

Air Pressure As Air Pressure decreases, so does density.

Atmosphere Atmosphere: a mixture of gases that surrounds Earth: acts like a blanket Contains oxygen Protects from sun

Layers of the Atmosphere Troposphere: all weather happens here Stratosphere: ozone layer-protects us Mesosphere: middle layer Thermosphere: hottest layer

Atmosphere

Composition of Troposphere Nitrogen=78% Oxygen=21% Other 1%=water vapor, CO2 and other

Weather Factors Sun’s energy travels to earth as Electromagnetic waves. What type of heat transfer is this?

Radiation Ever feel the heat of the sun on your face or the heat from standing by a campfire? That is radiation. It is the direct transfer of energy by electromagnetic waves through space.

Conduction Have you walked barefoot on the sand at the beach and the sand burned your feet? That is conduction. It is the direct transfer of heat from one substance to another through direct contact.

Convection Did you come in after the snow with wet shoes on and your mother told you to put them over the heating vent to dry? How does this dry them even though the actual furnace is in the attic? That is convection. The transfer of heat by the movement of fluid or air. Hot air rises, cold air sinks.

How is Earth heated? Light/heat from the sun RADIATES through the atmosphere, hits the Earth where it is absorbed. This heats the air above it by CONDUCTION. This heat rises up to the greenhouse gases where it is trapped, cools, sinks and heats at the surface again.-CONVECTION.

Weather Factors

Greenhouse Effect These gases absorb the heat and act as a “blanket” to keep Earth warm. Some greenhouse gases: water, methane, carbon dioxide.

Hot Air Rises… But how does the ground get hotter Hot Air Rises… But how does the ground get hotter??? … It is farther from the sun! Air in the atmosphere acts as a fluid (water vapor). The sun's radiation strikes the ground = warming the rocks/ground. As the ground’s temperature rises due to conduction, heat energy is released into the atmosphere, forming a “bubble” of air which is warmer than the surrounding air. This “bubble” of air rises into the atmosphere. As it rises, the air in the “bubble” cools and becomes more dense. The movement of the air creates wind. Convection currents are responsible for many weather patterns in the troposphere.

Convection Currents!

What causes winds? Lots of difference Differences in air pressure More of a difference in pressure = faster winds Lots of difference

Air Rises @ Equator Air Sinks @ Poles You know… Warm air rises = less dense Cool air sinks = more dense Now understand… Warm air = less dense = low pressure Cool air = more dense = high pressure

Global Winds Created by unequal heating of Earth’s surface. UNEQUAL HEATING DEMO 1

Global Winds… cont… The movement of air between the equator and the poles produces global winds. Coriolis effect produces patterns of air circulation called global winds.

Global Wind Belts Major global wind systems: Polar easterlies, westerlies, and trade winds.

Doldrums Where the trade winds meet around the equator Very little wind because the warm air rising = low pressure

Horse Latitudes High pressure areas… 300N and 300S Very week winds

Jet Streams Bands of high speed winds Upper troposphere and lower stratosphere Blow from west to east at speeds of 200-400 km/hr. Help airplanes save fuel and time when traveling east.

Local Winds Local winds are winds that blow over short distances. Have you ever flown a kite at the beach on a hot summer day? Even if there is no wind inland, there may be a cool breeze blowing in from the water toward the beach. This breeze is an example of local winds! Local winds are winds that blow over short distances. They are caused by unequal heating of Earth’s surface within a small area. Types: sea breezes and land breezes Mountain breeze and valley breeze

Sea Breeze (Morning) Land heats up faster than water. Hot air over land rises (Low Pressure), cool air over water falls (High Pressure). Winds move from the water (High Pressure) to the land (Low Pressure).

Land Breeze (Evening) Land cools off faster than water. Cool air over land falls (High Pressure), warm air over water rises (Low Pressure). Winds move from the land (High Pressure) to the water (Low Pressure).

Valley Breeze (Day) During the day the sun warms the air slopes, creating a valley breeze… at nightfall, the air along the mountain slopes cools…

Mountain Breeze (Night) This cool air moves down the slopes into the valley, producing a mountain breeze!

DEMO #1-__UNEQUAL HEATING OF EARTH-32.______________ LOOK AT THE EQUATOR

DEMO #1__UNEQUAL HEATING OF EARTH 33._______________ LOOK AT THE POLES

DEMO #2=_______HEATS UP FASTER DURING THE DAY AND ______COOLS FASTER AT NIGHT.

DEMO 2=____HEATS UP FASTER DURING THE DAY AND ____COOLS FASTER AT NIGHT

DEMO #4 LAND BREEZE HAPPENS ______________________

DEMO #3_SEA BREEZE HAPPENS ________________

Measuring Wind Winds are described by their direction and speed. Wind Vane Measuring Wind Anemometer – The cups catch the wind, turning faster when the wind blows faster. Winds are described by their direction and speed. Wind direction is determined with a wind vane – points in the direction the wind is moving! Wind speed is measured with an anemometer. The increased cooling that a wind can cause is called the wind chill factor.

Winds

Greenhouse Effect Roleplay Sun Gases Sun’s Rays

Weather Factors Scattering: Reflections of light in all directions. Why is the sky blue?