SOL 6.6

Atmosphere- The layer of gases that surrounds the planet.

The Atmosphere Introduction and Overview (about 3 minutes)

Earth's atmosphere makes conditions on Earth suitable for living things:

Contains oxygen and other gasesTraps energy from the sun to provide warmth to keep the water on our planet in liquid formProtects from dangerous radiation from the sunPrevents meteoroids from hitting Earth's surface

CFU (Check For Understanding): How does the atmosphere make conditions

on Earth suitable for living things?

Weather= is the condition of Earth's atmosphere at a particular time and place.

CFU: Give an example of weather.

Earth's atmosphere is made up of nitrogen, oxygen, carbon dioxide, water vapor, and many other gases, as well as particles of liquids and solids.

Nitrogen 78%Oxygen 21%Other 1%

CFU: What is the most abundant gas in the atmosphere?

These gases cycle between the atmosphere and living things, ensuring that air supply on Earth will not run out.

CFU: Why don’t we run out of these gases?

Makes up most of the air we breathe (3/4).Living things must have nitrogen to grow and repair body cells.We do not get nitrogen directly from the air but through the nitrogen cycle.

CFU: How do we attain (get) Nitrogen?

2nd most abundant, but makes up less than ¼ of the air we breathe.Living things use it to release energy from foodFires use oxygen to burn

CFU: Why do we need Oxygen?

Carbon Dioxide is essential to life even though its makes up only a small part of the atmosphere.Plants use it to produce food. Animals give off CO2 as a waste product. Burning fuels increases the amount of CO2 in the atmosphere, which may be raising Earth's temperatures.

CFU: How could too much CO2 be bad for Earth?

Air is not dry, because it contains water vapor, or water in the form of a gas.

It is invisible.It is not the same as steam.The amount of water vapor in the air varies from place to place and from time to time on Earth.Water Vapor plays an important role in Earth's weather.

CFU: Describe water vapor in the atmosphere.

In the real world, air also contains tiny solid and liquid particles of dust, smoke, salt and other chemicals.

Any change to the atmosphere that has harmful effects is called air pollution.

Pollutants are substances that cause pollution.Pollution can affect the health of humans and other living things and can affect the climate of the whole planet. Solid particles released into the air are called emissions.

CFU: Describe pollution.

• Emissions from cars, trucks, and airplanes

• Eruption of volcanoes• Burning coal (up until mid

1900's)

Smog= a thick, brownish haze formed when certain gases in the air react with sunlight.

The major sources of smog are the gases emitted by cars and trucks.

The gases react with sunlight and produce a form of oxygen called ozone, which is toxic and found in smog. The ozone in smog can cause lung problems and harm the body’s defenses against infection.

CFU: What are the main causes of smog?

Air found indoors can also be polluted by dust, pet hair, air-freshener, asbestos, and cigarette smoke.

Carbon Monoxide is a colorless, odorless gas that forms when wood, coal, oil or gas are incompletely burned. When it builds up in a closed space, such as a basement, apartment or house, it can be deadly. There are carbon monoxide detectors.

CFU: What are some causes of indoor air pollution?

Radon is a colorless, odorless gas that is radioactive. It is formed naturally by certain rocks underground and can enter homes through cracks in basement walls or floors. Breathing it in over many years can cause lung cancer and other health problems. Ventilation systems prevent this.

CFU: Where does radon come from?

Some changes to the atmosphere affect the climate of the whole planet.

In the atmosphere, water vapor, carbon dioxide and other gases act like windows and prevent heat from the sun from escaping back into space. This is called the greenhouse effect and makes the Earth warm enough for living things to survive.

CFU: Describe the Greenhouse Effect in your own words.

The theory of global warming predicts that the increase in carbon dioxide will cause the average temperature of Earth to continue to rise, causing a huge impact.

CFU: What is global warming?

Because air has mass, it also has other properties, including density and pressure. Air pressure is the result of the weight of a column of air pushing down on an area.

We can measure changes in air pressure using a barometer.

The column of air above your desk is about the same as the weight of a large school bus!!!...but...the air molecules push in all directions and not just down on your desk!

CFU: What do you measure air pressure with?

The four main layers of the atmosphere are classified according to changes in temperature.

TroposphereStratosphereMesosphereThermosphere

Troposphere

Inner, lowest layer of the atmosphere (0-12 km above Earth's surface)“Tropo-” means “turning” or “changing”Conditions are more variable here than any other layer.Where Earth's weather occursContains almost all of the mass of the atmosphere even though its the shallowest layer.

CFU: Describe the Troposphere in your own words.

Stratosphere

Layer above the troposphere “Strato” means “layer” or “spreading out”12 to 50 km above Earth's surfaceLower stratosphere is about -60 degrees CelsiusUpper stratosphere is warmer than the lower stratosphere because it contains a layer of ozone

CFU: Describe the Stratosphere in your own words.

Mesosphere

Above the stratosphere“Meso-” means “middle” and it is often called the middle layer.50 - 80 km above Earth's surfaceTemperatures approach -90 degrees CelsiusProtects Earth's surface from being hit by most meteoroids.A shooting star is really a meteoroid burning up in Earth's mesosphere.

CFU: What does the Mesosphere protect us from?

Thermosphere

Very thin airOutermost layer of the atmosphere80 km above Earth's surfaceNo defined outer limit-blends gradually with outer space“thermo-” means “heat”Up to 1800 degrees Celsius

CFU: Describe the Thermosphere in your own words.

Thermosphere is divided into 2 layers:

Ionosphere-lower layer (80-550 km) The Northern Lights (aurora borealis) occur in this layer.

Exosphere- outer layer (550-? km) Satellites are found here.