Why do we get day and night? - BBC Bitesize

Key information

In this Space article you can find out about:

  • the Earth, Sun and Moon
  • why we get day and night
  • what we can see during the day and at night
  • why days and nights are different at different times of year.

And you can test what you've learned with some activities!

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Day and night

Day and night look very different.

Do you ever look up at the sky?What can you see during the day?What can you see at night?

Image gallerySkip image gallerySlide 1 of 5, , If you look up on a clear day the sky is bright and you can see the Sun. You should never look at the Sun directly. It can damage your eyes.

Quiz

In the day time it is normally light.

In the morning we have our breakfast and go to nursery or school.

In the afternoon we go home and in the evening we go to bed.

Flick through the photos and say whether you’d be doing these things in the morning, afternoon or evening.

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Why do we get day and night?

Watch

The Earth is always turning around slowly even though you can’t see or feel us turning.

The part of the Earth that is facing the Sun has the Sun’s light shining on it and has daytime.

The part of the Earth facing away from the Sun is in darkness and has night time.

So when it is day time we are facing towards the Sun but as the Earth spins and we turn away from the Sun, we move into night time.

Look at this picture and then try and answer the questions about it.

Can you tell where the Sun is compared to the Earth?

What difference can you see between Scotland and Australia?

In winter nights are really long and days are short. So it will be dark in the morning when you get up and dark long before you go to bed.

In summer the days are really long and the nights are much shorter. It will be daylight when you get up and go to bed.

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Earth

We live on a planet called Earth. This is what Earth looks like from space.

Image source, NASA

The Earth is the shape of a ball, and we call this a sphere.

The yellow and green areas show where there is land.The blue parts are sea.The white areas show clouds.

We can see all these clearly because they are lit up by the Sun.

Image source, NASA

The Earth looks very different at night.

Everything looks much darker. That is because this part of the Earth is not lit up by the Sun.

Can you see some bright spots? These are where there are cities and towns. They look bright because of lights in the streets, or from buildings or traffic.

You can still see clouds but these look much darker than before because they are not lit up by the Sun.

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What is the Sun?

The Sun is a star but it doesn't look like other stars. That is because it is much, much closer to Earth than any other stars.

Like all stars, the Sun is a big ball of gas. All this gas is so hot that it glows, just like a fire does.

The Sun gives us light that makes our days bright. And heat from the Sun keeps our planet warm enough to live on.

Image source, NASA

The Sun is too bright to look at. It is so bright that it can damage your eyes or even cameras pointing at it.

This photograph of the Sun has been taken with special filters that protect the camera and make the picture darker so we can see details of the Sun's surface.

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What is the Moon?

The Moon is a ball of rock which spins around the Earth.

It does not give out light like a star. The Moon looks bright because it reflects light from the Sun.

Just like the Earth, the side of the Moon facing the Sun is lit up. The other side is in shadow.

The Moon is always a sphere. But it sometimes appears to be a different shape.

Sometimes we can see all of the side of the Moon that is lit up. Sometimes we see some of the lit up side and some of the side in shadow. This is why the Moon seems to change shape.

Image source, NASA
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Travelling to the moon

People called astronauts have been to the moon. The moon is made of rock.

They travelled to the moon in a rocket and need special suits to protect them.

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