1. Work in small groups.

1. Can you name all of the planets?

2. Can you put them in order from the Sun?

3. Which planet is the biggest?

4. Which planet is the smallest?

2. Study the picture and answer the questions in small groups.

1. Is the Moon smaller than, bigger than or the same size as the Earth?

2. What is the average distance between the Earth and the Moon?

3. What is the average distance between the Earth and the Sun?

4. What is the mean diameter of the Earth, the Sun and the Moon?

Reading and Listening: Observatories

3. Match the words to their definitions.

1. Astronomy   2. Telescope 3. Observatory 4. Lunar eclipse 5. The Sun

a) This occurs when the Moon passes directly behind the Earth and enters into its shadow. b) Our closest star c)  The scientific study of space. d)  A place where astronomy is studied. e) An optical instrument that makes objects seem larger and nearer

The universe is everything that exists. It is so enormous that scientists cannot measure distances in kilometres; they have to use light years. A light year is the time it takes for light to travel in one year; 10 trillion kilometres! Nothing travels faster than light. Light travels at 299 792 458 metres per second!

Our Universe is amazing!

What does the universe contain?

The universe contains celestial bodies. Celestial bodies are nebulae, stars, galaxies, comets, asteroids, meteorites, satellites, planets and dwarf planets.

Nebulae, stars and galaxies

• Nebulae are clouds that are made up of dust and different types of gases that form stars. Stars are made inside a nebula.
• Stars are huge spheres of very hot, glowing gas. Stars produce their own light and energy. The Sun is a star.
• Galaxies are groups of millions of stars and nebulae.

A visual representation of a galaxy

Satellites, comets and asteroids

• Satellites are objects that move around larger objects. The Moon is a satellite.
• Comets are big balls of ice, mud and rock; they look like they have tails. When a comet approaches the Sun, its tail is behind it. When it moves away from the Sun, its tail is in front. A comet’s tail always points away from the Sun.
• Asteroids are large rocks travelling in space; they revolve around stars and planets.
• Meteorites are asteroids that crash into planets or stars.

Planets and dwarf planets

• Planets orbit stars; they can be made of rock or gas and are large spherical bodies. The Earth is an example of a planet. A planet does not emit its own light, but reflects the Sun’s light.
• Dwarf planets are smaller than planets. An example of a dwarf planet is Ceres, which is located on the asteroid belt between the orbits of Mars and Jupiter. Ceres is larger than the Iberian Peninsula, and scientists using the Herschel telescope have discovered water vapour on its surface. This means that this dwarf planet could have living organisms on it!

1. Choose the correct answer.

1 We use kilometres / light years to measure distances in the universe.

2 Stars are formed inside / outside of a nebula.

2. Name a celestial body that is made of ice and rock.

3. Choose the correct answer.

The Moon is .

 a) ... a satellite.                               b) ... a comet.                                  c) ... an asteroid.

4. Are these sentences True or False? Correct the false ones.

 1.  Planets orbit stars.

2.  The Earth is a star.

3.  A planet is smaller than a dwarf planet.

 4.  Planets are spherical in shape.

 5.  A planet emits its own light.

6.  Comets have tails.

A planetary system is a group of planets in the same area that orbit a star. The Earth belongs to the planetary system called the Solar System.

The Solar System 

Our Solar System is made up of all the celestial bodies that orbit the Sun. It is in the galaxy called the Milky Way.

The star that we call the Sun is at the centre of the Solar System. It is an enormous ball of gas. More than 1 400 000 Earths could fit inside of the Sun! All of the other celestial bodies orbit around the sun. They do not orbit it in a perfect circle; they orbit it in an elliptical shape.

The Sun provides light and thermal energy. The Earth is at the perfect distance from the Sun to allow us to have life on Earth. It takes 365 days for the Earth to rotate around the Sun. Between the orbits of Mars and Jupiter are a group of rocks, called the asteroid belt.

Many of the other planets in our Solar System also have moons. Both Jupiter and Saturn have more than 60 different moons; each moon is a different size and follows a different orbit around its planet.

Sci-find

Investigate why we can´t see any stars during the day time. Shere your findings with your class.

1. Find and correct the five mistakes in this paragraph.

A group of planets that orbit a star is called a planetary circle. The Earth is at the centre of the Solar System. All of the celestial bodies orbit around it. The Sun gives us light and kinetic energy. It takes 366 days for the Earth to rotate around the Sun. No other planets have moons.

2. What am I?

1.  I’m a galaxy that contains the Solar System.
2.  I last 365 days.
3.  I’m a group of planets orbiting a star.
4.  I’m a group of rocks between Mars and Jupiter.
5.  I’m a star at the centre of the Solar System.

3. Study the picture of the Solar System and answer the questions.

1.  What are the names of the planets in the Solar System?

2.  Name a dwarf planet.

3.  What is the name of the satellite that orbits the Earth?

4.  What are the paths of the planets called?

5.  Where is the asteroid belt?

4. Name the following planets.

1.  The closest planet to the Sun.

2.  The third planet from the Sun.

3.  The fifth planet from the Sun.

4.  The furthest planet from the Sun.

5.  The biggest planet.

5. Do you think that it takes all of the planets the same amount of time to orbit the Sun? Why or why not?

6.  Do the space quiz! Can you guess which sentences are true?

1. There are more stars in space than grains of sand on Earth.

2.  It is possible to snore in space.

3.  Venus takes its name from the Roman goddess of love.

4.  If you cry in space, your tears flow upwards.

The Earth is the third planet from the Sun. It was formed more than four and a half billion years ago and is the only planet known to have life.

The Earth rotates around an imaginary line or central axis as it orbits the Sun. The axis of rotation is tilted with respect to the Sun around 23º.

If we draw an imaginary line through the Earth, the place where the line meets the surface of the Earth in the north is called the North Pole and in the South it is called the South Pole.

If we look at the Earth from above, from the north, it rotates counterclockwise, from east to west, around its own axis. It takes the Earth around 24 hours to complete one
rotation.

The imaginary line around the Earth’s surface that is an equal distance to the poles is called the Equator.

The Equator divides the Earth into the Northern Hemisphere and the Southern Hemisphere.

Seasons in the Northern and Southern Hemisphere 

As we have seen, the Earth is tilted. This tilt in the Earth’s axis affects the seasons in both hemispheres.

When the North Pole is tilted towards the Sun, it is summer in the Northern Hemisphere and winter in the Southern Hemisphere. When the North Pole is tilted away from the Sun, it is winter in the Northern
Hemisphere and summer in the Southern Hemisphere.

The exact dates of the equinoxes and solstices change every year.

Equinoxes and solstices

The equinoxes are the days that the Sun shines directly on top of the Equator. On these days, there are twelve hours of light all over the world. The summer solstice is the longest day of the year and the winter solstice is the shortest. When the days of sunlight are increasing in one hemisphere, they are decreasing in the other. At the Equator, the Sun rises and sets faster than at any other point on Earth.

1. What information do these numbers relate to?

a) 24

b) 3rd

c) 365

2.  Are these sentences True or False? Correct the false ones.

3.       1.  The Earth is the fifth planet from the Sun.

2.  Rotation and orbit are the same.

3.  The Earth rotates around an imaginary line or axis.

4.  One day on Earth is the same as one complete rotation.

5.  The Equator separates the Earth into the North and South Pole.

6.  The Earth rotates clockwise.

3.  Study the picture and answer the questions.

1.  When is it spring in the Northern Hemisphere?

2.  When is it summer in the Southern Hemisphere?

3. What is it like in the Arctic Circle when summer begins in the Northern Hemisphere. Why?

4. How do you think the weather would be affected if the Earth didn’t tilt?

The Earth is divided into three layers: the atmosphere, the hydrosphere and the geosphere.

• The atmosphere is the layer that contains the Earth’s air and surrounds the planet. It is about 1 000 km thick.
• The hydrosphere consists of all of the water on Earth in its three states of liquid, solid and gas (vapour).
• The geosphere is the densest part of the Earth; it is mainly rock.

The layers of the geosphere (I)

The Earth is made up of different layers. The four main layers are:

• The crust
• The mantle
• The outer core
• The inner core

The layers of the geosphere (II)

Inner core:

• Made of iron and nickel
• Thought to be solid
• About 6 000 ºC

Outer core:

• Made of liquid iron and nickel
• Encloses Earth’s core
• Creates a protective magnetic field around Earth that stops solar flares from the Sun; protects life on Earth

Mantle:

• Made of rock containing iron and magnesium
• Makes up about 84% of the size or volume of Earth

Crust:

• Made of various minerals and rocks
• 7-70 km thick; the thickest part is called the continental crust

 The Moon

The Moon is a spherical rock and the Earth’s only satellite. It orbits the Earth, trapped by the Earth’s gravitational pull. It takes about 29 days for the Moon to make one complete rotation and orbit.

• The Moon has no atmosphere or hydrosphere and its surface is covered in craters, left by meteors.
• During a month, the Moon appears to change shape. This is because, as the Moon goes around the Earth, the light of the Sun illuminates different angles of the Moon. These are called the lunar phases.
• The Moon has its own gravitational pull which causes high and low tides. The tides of the ocean change about every six hours due to the changing position of the Moon.
• When the Moon is between the Sun and the Earth, an eclipse occurs which means that the Sun is hidden behind the Moon.

1. Which layer of the Earth…

1 contains all of the water found in its three different states?

2 surrounds the entire planet and contains air?

3 is made up of mainly rocks?

2. Study the image of the geosphere. In which layer do we live?

3.  Which layer of geosphere do you think is the hottest? Explain your answer.

4.  What layer of the Earth creates a magnetic field around the planet that protects the atmosphere from solar flares?

5.  What is the thickest part of the Earth’s crust called?

6.  Name two metals that can be found in the Earth’s core.

The atmosphere is very important to our survival on Earth. It regulates the planet’s temperature, and protects us from the Sun’s dangerous radioactive rays.

The atmosphere is divided into different layers.

• The troposphere is the part of the atmosphere that is closest to Earth. It contains most of the air that we breathe. The air moves up and down, creating most of the weather on Earth. It contains most of the water vapour which forms into clouds.
• The stratosphere is above the troposphere. The air moves very quickly, parallel to the Earth. This is the area where most aeroplanes fly because they use less fuel here. The currents are called jet streams. The stratosphere contains a substance called ozone which protects us from the Sun’s harmful ultraviolet rays.
• The mesosphere is above the stratosphere. It is the coldest area of the atmosphere. The temperature can drop to -130 °C. It is here that meteorites that come close to the Earth burn up, and we can see them as shooting stars.
• The thermosphere is above the mesosphere. The International Space Station has a satellite here that people work inside. You can see it from Earth! Here temperatures can reach 2,000 °C in the highest part and can drop by 200 ºC at night.
• The exosphere has a thin atmosphere where the lightest gases are. The Hubble telescope orbits here.

Atmospheric phenomena

• Clouds are formed by water vapour. Water on Earth evaporates and rises because of the heat of the Sun. These water droplets attach themselves to dust particles in the air and join together to form clouds. When the clouds become very heavy, the water droplets fall as rain or snow depending on the temperature.

• Precipitation can fall from the clouds as snow, rain, or hail; depending on the temperature at which water droplets condense inside the cloud.

• Wind is produced when air becomes warmer and rises, while other air currents cool and sink. The movement of hot and cold air produces wind.

• Storms happen when masses of hot and cold air collide. In the thundercloud, rain and ice collide, creating an electrical charge. The charge jumps from the clouds towards the Earth. The giant spark of electricity is lightning. Thunder is the sound that lightening makes when it disappears and air rushes into the space that it leaves behind.

    1.  Where is most of the Earth’s weather created?

2. Why do aeroplanes generally fly in the stratosphere?

3.  What is the difference between how the air in the troposphere and stratosphere moves?

4.   Which layer has the lowest temperatures?

5.  Where are people working in the thermosphere?

6.  Which atmospheric phenomena is being described?

1.  This occurs when air becomes warmer and rises and cool air sinks.

2.  This occurs when an electrical charge is formed in a cloud.

3.  This occurs when water vapour attaches itself to dust particles.

4.  This can fall from the clouds as snow, rain or hail.

5.  This happens when masses of cold and hot air collide.

7.  If you count the seconds that pass from seeing lightning to hearing thunder, you can calculate how far away a storm is. Thunder travels at about 1km every three seconds. So, after you see a bolt of lightning, start counting and for every count of three the storm is 1 km away. If you count 9 seconds between seeing lightning and hearing thunder, how far away is the storm?

Sci-find

Investigate the differences between a storm and a hurricane.

What is a hurricane?

What is the centre of a hurricane called and what are conditions like there?

How does a hurricane move?

The Earth’s crust is relatively small. It only occupies 1% of the Earth’s total volume, but it is extremely important because humans can live on the crust. The crust is made of many different sheets of rock, or tectonic plates, which float on top of the Earth’s mantle.

The Earth’s crust is home to an amazing variety of plant, animal and human life as well as diverse geographical features.

The four main landforms on Earth are: mountain ranges, plains, plateaus, and valleys.

The continents

• The American continent, consisting of North, Central and South America and the Caribbean, is the second-largest continent on Earth. Its topography varies from enormous mountain ranges, such as the Rocky Mountains and the Andean mountains, to broad valleys.
• The African continent is dominated by plateaus, rather than mountains. The largest desert in the world, the Sahara desert, is located on the northern part of the continent.
• Europe is a smaller continent. The northern and southern parts of the continent are the most mountainous. The Pyrenean mountain range is found in Europe. The central part of the continent is home to the Great European Plain.
• Asia is the largest continent on the planet, and is also one of the most mountainous continents. It is home to the Himalayan mountain range, which has the world’s highest point, Mount Everest. The peak of Mount Everest is 8,848 m high.
• Oceania is the smallest continent, and is formed by many islands, including the largest island, Australia. Australia is mostly flat, but has some interesting rock formations, such as the famous landmark Uluru, which is also known as Ayers Rock.
• Antarctica has large mountains which are hidden beneath huge sheets of ice. Its glaciers are some of the oldest and largest on Earth.

    1. Which continent has the largest desert?

2.  What are the sheets of rock that float on the Earth’s mantle called?

3.  Look at the map and answer the questions.

1 Which area has the highest altitude?

2 Which areas are covered in ice?

3 How could we describe the general relief of Europe?

Sci-find 

What happens when tectonic plates collide? Find out!

Project 1: A Solar Eclipse

A solar eclipse happens when the Moon passes between the Earth and the Sun, covering the light from the Sun. As we have seen, the Moon is much smaller than the Sun, so how can the Moon cover the Sun?

Steps:

Step 1 Make a ball of modelling clay and stick a pencil in it. Fix the pencil to some modelling clay on the table, this represents the Sun. Take a smaller ball of modelling clay and fix it to the top of a pencil. This represents the Moon.

Step 2 Place the Moon in front of the Sun. It is much smaller, does it cover the Sun?

Step 3 Now, slowly move the Moon away from the Sun towards your face until you cannot see the Sun. The Moon now covers the Sun. Has the Moon gotten bigger?

The Sun is about 150 million kilometres away but the Moon is only 384,400 kilometres away. Because the Moon is so much closer to us, it looks like it covers the Sun, even though the Sun is much larger.

Project 2 Life on other planets

Do you believe that it is possible that life can exist on other planets?

Write 200 words explaining your reasons.

Think about the following when writing:

• What would the planet need to support life?
• Why has nobody discovered life on other planets yet?
• Would alien life have the same physical appearance as us?
• How could we communicate with alien life?

Imagine that you have discovered life on another planet.

Describe:

• How big the planet is.
• How long a day and night is.
• How long a year is.
• What the temperature is.
• What the alien life looks like.
• How alien life survives

Present your ideas to the class.