The Atmosphere is the layer of air surrounding the Earth

The gases in the atmosphere are important because: ◦ They block out dangerous rays from the sun, such

as UV rays ◦ They stabilize the temperature across the Earth by

retaining heat ◦ They include O2, which is essential for cellular

respiration, and CO2, which is necessary for photosynthesis.

Atmospheric pressure is cause by gravity pulling down the particles of the atmosphere

This is why atmospheric pressure decreases as you rise in the atmosphere.

99% of the particles is present in the first 30 km above the surface

The atmosphere is considered to extend more than 10,000 km above the surface

Air is a mixture of gases, especially nitrogen and oxygen, that makes up the atmosphere

78% of air is Nitrogen

21% of air is Oxygen

1% of air is other gases

Water only makes up a small portion of the air, but is still very important

Atmospheric circulation is the global-scale movement of the layer of air surrounding the Earth

The hot air rises and the cooler air drops

This is due to convection.

Without this movement, the temperature difference between the equator and the poles would be much greater

An air mass is a large expanse of the atmosphere with relatively uniform temperature and humidity

When two air masses collide, they do not simply combine

The cooler air mass slides below the warmer and the warmer air mass rises

Where warm and cold air masses collide is referred to as a front

Cold fronts occur when a mass of cold air meets a warm air mass

As the warm air rises it cools quickly and condenses into clouds

This produces puffy clouds called cumulus

A warm front is when a warm air mass meets a mass of cold air

In this case, the warm air rises more slowly forming light clouds called nimbostratus

On weather maps, cold fronts are represented by blue arrows and warm fronts are represented by red arrows

While most air masses move horizontally over the surface of the Earth, there is some vertical movement

An area of atmospheric circulation surrounding a high pressure center

Clockwise for Northern hemisphere and counter-clockwise in the Southern hemisphere

An area of atmospheric circulation surrounding a low pressure center

Counter-clockwise for Northern hemisphere and clockwise in the Southern hemisphere

Strong depressions sometimes form over warm waters of tropical oceans

A huge spiral forms which can stretch up to 800 km across in diameter

Winds can blow up to 360 km/h

These storms can be called cyclones, hurricanes or typhoons depending on the region

Hurricanes have a characteristic eye in the center ◦ Typically they are between 30-65 km wide

◦ Can be as little as 3 km up to 670 km

The eye is generally calm and without clouds

The walls of the eye, the eyewall, are generally the tallest, strongest and most rainy parts of the hurricane

What are greenhouse gases? ◦ Mainly water vapour (H2O), Carbon Dioxide (CO2),

Methane (CH4) and Nitrous Oxide (N2O)

◦ They are present in the atmosphere and they act as a type of insulation to retain the heat around the Earth.

Without this effect, the Earth’s average temperature would be -18°C

1- Most of the Sun’s rays reach the Earth’s surface and is absorbed by the ground

2- The heated ground sends infrared rays back into the atmosphere. A portion of the infrared rays pass through the atmosphere and are lost into space.

3- Greenhouse gases trap some of the rays and send them back to the Earth, further heating its surface

Over the last century, the levels of CO2 have increased due to combustion of fossil fuels

Human activities have increased the production of CO2 by billions of tonnes which is having a big effect on the environment

This is leading to climate change on the Earth

Methane, CH4, has a 21 time greater effect on the greenhouse effect than CO2, for the same volume

CH4 comes from the digestion in farm animals, and decomposition of garbage and waste

N2O comes from the strong use of nitrogen rich fertilizers on farms

Wind Energy is the energy that can be drawn from the wind

Wind turbines are huge machines which turn with the wind and produce electricity

Wind is a renewable resource so wind turbines are considered to be environmentally friendly

Wind turbines do have a few negatives though

People say that wind turbines ruin the natural beauty of the landscapes

Wind is not a reliable source of power since the winds are not predictable

Wind energy cannot be stored. Once the wind is gone, so is the electricity

The Sun and the Moon are the two bodies in our solar system which most affect us

The Sun is vitally important because its energy provides us with light and heat

The Moon exerts gravitational forces upon the Earth which explains the tides.

The Sun is composed 75 percent of Hydrogen and 25 percent Helium

The temperature of the core reaches up to 15 million °C due to nuclear Fission ◦ Hydrogen being made into Helium

Light only takes 8 minutes to reach the Earth from the Sun ◦ The Earth is 150,000,000 km away from the Sun

Solar radiation contains all of the waves in the electromagnetic spectrum

Only visible light, some infrared, and a small amount of UV light reach the surface of the Earth

Due to the curvature of the Earth, the equator receives much more heat than the polar regions

The Earth receives enough energy in one hour from the sun to satisfy the world’s energy requirements for a year. ◦ Solar energy is the energy that comes from the Sun

in the form of radiation through the atmosphere

Harnessing this energy is a huge challenge

There are a few ways that we can harness the power of the Sun

Passive Heating Systems ◦ By positioning the house to take advantage of the

Sun.

Photovoltaic Cells ◦ When the material that makes up the cells is hit by

light, electrons are set into motion. This causes a current which can be used to power small appliances or an entire house

Solar Collectors ◦ These are sheets of glass which has copper pipes

below it to absorb to heat up water or air for homes or water for a pool

The moon has been revolving around the Earth for billions of years

Its average diameter is 3476km, which is roughly a quarter of the Earth

The theory behind the origin of the Moon is that the Earth was struck by a meteor the size of Mars. This caused part of the Earth to explode

The pieces reunited to form the Moon

The Moon not only rotates around the Earth, but also rotates on its own axis.

These two movements are synchronised to that both rotations take the same amount of time (27.3 days)

Water masses on the side closest to the Moon are attracted to it

As a result, they will swell, forming a slight bulge in the Moon’s direction

Also, the waters on the opposite side of the moon get pulled towards the moon as well.

Tidal energy is the energy obtained from the ebb and flow of the tides

Works similarly to hydroelectric dam

When the tide come in, it fills a huge basin

The water remains there until the tide goes out again

The gate opens, releasing the basin of water to flow through the turbines

The turbine is set into motion, generating electricity

There are numerous advantages

Produces no greenhouse emissions

Entirely renewable

Perfectly reliable since meteorologists can predict the ebb and flow of tides

Building plants is complex and costly because they have to stand up to harsh conditions

There are few suitable sites in the world for building this type of power plant

There must be a tidal range of at least 5 meters