THE ATMOSPHERE AND ATMOSPHERIC PHENOMENA

Refresh Which gases do we need to live?

12 The atmosphere

The atmosphere is the layer of gases that surrounds the Earth. It is essential for life on the planet because it is a shield that keeps the Sun’s radiation away and protects the surface of Earth from the impact of meteorites. It also helps to regulate the Earth’s temperature and keep it within the range that is suitable for life. The combination of gases that form the atmosphere makes life possible. They are mostly nitrogen and oxygen, but there are other gases.

Exosphere: there are few gas particles here because they are less affected by the Earth’s gravity. They are not very dense. This the layer that is closest to outer space.

Thermosphere: satellites and space stations orbit in this layer. It is very hot and can reach 2000 ºC.

Mesosphere: it protects us from the impact of meteorites because its gases delete cause friction. This makes the meteorites heat up and burn.

Stratosphere: the ozone in this layer protects life from the Sun’s harmful UV radiation. Life would be impossible without this protection.

Troposphere: This is where atmospheric phenomena happen. It is the thinnest at the Earth’s poles. It is formed by dense gases, such as nitrogen and oxygen, but it also contains argon, water vapour and carbon dioxide.

1 In your notebook, copy and complete the sentences about the Earth’s atmosphere.

a) The atmosphere is...

b) It contains gases that… c) It protects the surface of the planet from… d) It stops the Sun’s… e) It keeps … a) Which layer is closest to Earth? b) Which layer is least affected by gravity? c) Which layer that stops radiation? d) Which layer is the hottest?

2 Answer the questions about the layers of the atmosphere in your notebook.

13 The weather

Weather is how the term we use to refer to the events that are happening in the troposphere at a specific moment. For example, when the air is cold and humid, it will rain. The weather has got a big influence on our daily activities and it can have devastating consequences when it is extreme. The science that studies the weather is called meteorology. It predicts the weather so that we can be prepared.

Language Bank

Present continuous for future plans

14 Atmospheric phenomena

Clouds: they are formed when the water that evaporates because of the heat of the Sun joins with dust particles in the air.

Precipitation: when clouds are full of evaporated water, they precipitate. This precipitation can fall as rain, hail, sleet or snow, depending on the air temperature.

Wind: it is produced when two masses of air at different temperatures meet. Hot air rises and cold air sinks. This movement produces wind.

Weather front: it is the boundary between masses of hot and cold air. There is a lot of electric activity here and this causes large electric discharges that we call lightning. Sometimes, the quick movement of the air masses causes clouds to form, so there is heavy rain too. These are storms.

I want to see the stars! Please turn off those lights!

1 Kim and her friends are really interested in the observation of stars and are organising a session with an astronomer who can show them different constellations. Is this street a good place for this session? Why/Why not?

2 Talk to a friend and choose the elements that make it difficult to see stars where Kim is.

a) Street lights b) Light from the shop windows c) Light from the restaurant signs d) Light from people’s houses a) Which areas have got more light pollution? b) What kind of areas are they? c) Where can you go if you want a clear sky to look at the stars?

3 Look at the photo above and answer the questions.

4 Which of the streetlights causes the least light pollution?

Think 5 It is important to raise awareness about light pollution. Think of actions that can reduce light pollution at night in a populated area and prepare a leaflet to share this information with the rest of the class.

6 Organise a symbolic protest. Agree with your classmates on a time this evening when you are all at home. Turn off the lights for a minute and explain to your parents why this action is important for the environment. Then, share your experience with your classmates.

We’re studying the universe in school today, so we can dress as aliens!

Look, here come Kim and Pat. They look great too!

I... AM... AN... ALIEN ...FROM... A... DISTANT... PLANET.

I AM AN ALIEN! What are you doing to your planet? You must look after it!

1

Oh no, those children are breaking branches and pulling up plants.

They think Ben really is an alien! Haha, I bet they won’t pull plants up again!

We’re sorry. We’ll fix everything.

What are the small children doing that upsets Kim, Sol and Ben?

Think 2 Why do you think the children do as Ben asks? 3

What other things can we do to protect the natural environment?

1 Think, read and fill in the gaps.