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Year 3 Science Earth and Space Sciences

Earth, Sun and Moon

Why do we have day and night? What causes the seasons? Let's explore our place in space!

Day and Night

The Earth spins (rotates) like a top. One full spin takes 24 hours — that is one day! The side facing the Sun has daytime. The side facing away has night-time.

☀️

The Sun

Our star

→ →
🌎

Earth

Spins around once every 24 hours

☀️ Day

Side facing the Sun

🌙 Night

Side away from the Sun

☀️ The Sun — Our Star

The Sun is a star — a giant ball of burning gas. It gives us light and heat. Without the Sun, Earth would be dark and freezing cold!

Amazing Sun Facts

  • ● The Sun is about 150 million kilometres from Earth
  • ● Light from the Sun takes about 8 minutes to reach us
  • ● The Sun is so big that over 1 million Earths could fit inside it
  • Never look directly at the Sun — it can damage your eyes!

🌙 The Moon and Its Phases

The Moon orbits (goes around) the Earth. It takes about 28 days to go all the way around. The Moon does not make its own light — it reflects light from the Sun.

As the Moon moves around Earth, we see different amounts of its lit side. These are called phases.

Moon Phases

🌑

New Moon

🌒

Waxing Crescent

🌓

First Quarter

🌔

Waxing Gibbous

🌕

Full Moon

🌖

Waning Gibbous

🌗

Last Quarter

🌘

Waning Crescent

Why Do We Have Seasons?

The Earth is slightly tilted as it orbits the Sun. This tilt means that different parts of Earth get more or less sunlight during the year, giving us seasons.

☀️ Summer

Your part of Earth is tilted towards the Sun. More sunlight = warmer and longer days.

❄️ Winter

Your part of Earth is tilted away from the Sun. Less sunlight = colder and shorter days.

When it is summer in Australia (Southern Hemisphere), it is winter in Europe (Northern Hemisphere)!

💡 Think About It!

If the Earth was not tilted, would we still have seasons? What makes you say that?

🧪 Try It at Home!

Day and Night Model

You will need: a torch (flashlight) and a ball (or an orange).

  1. Go into a dark room
  2. The torch is the Sun. The ball is the Earth.
  3. Shine the torch at the ball. One side is lit up (day), one side is dark (night).
  4. Slowly spin the ball. Watch how different sides have day and night!
  5. Put a small sticker on the ball to represent where you live. Watch it go from day to night as it spins.

Key Vocabulary

Rotate

To spin around. The Earth rotates once every 24 hours, giving us day and night.

Orbit

To travel around something in a path. Earth orbits the Sun. The Moon orbits Earth.

Axis

An imaginary line through the centre of Earth that it spins around. It is slightly tilted.

Phase

The different shapes of the Moon we see as it orbits Earth (new, quarter, full, etc.).

Knowledge Check

Choose the correct answer for each question. Click "Check Answer" to see if you are right!

Question 1

What causes day and night on Earth?

Question 2

How long does it take the Moon to orbit the Earth?

Question 3

The Sun is a...

Question 4

When it is summer in Australia, what season is it in the United Kingdom?

Question 5

Which moon phase shows the Moon completely lit up?

Key Concepts Summary

Year 2: Solids Liquids Year 3: Forces Motion