Space Revision — KS3

Work through each section, watch the videos, and test yourself with quizzes and activities. Tasks are colour-coded by difficulty.

Foundation Core Stretch
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Our Solar System

Our solar system is made up of the Sun and everything that orbits around it. This includes 8 planets, their moons, dwarf planets (like Pluto), asteroids, and comets.

The Sun sits at the centre. It is a star — a massive ball of hot gas that gives off light and heat through nuclear fusion. The Sun's gravity keeps everything orbiting around it.

Memory Trick — Planet Order
My Very Easy Method Just Speeds Up Naming

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

The Planets

The 4 planets closest to the Sun are called the rocky (terrestrial) planets: Mercury, Venus, Earth, and Mars. They are small and made of rock and metal.

The 4 outer planets are called the gas giants: Jupiter, Saturn, Uranus, and Neptune. They are much larger and made mostly of gas and ice.

Fun Fact: Jupiter is so big that over 1,300 Earths could fit inside it. If Jupiter were a football, Earth would be smaller than a marble!

Other Objects

Asteroids are chunks of rock and metal that orbit the Sun, mostly found in the asteroid belt between Mars and Jupiter.

Comets are balls of ice, rock and dust. When they get close to the Sun, they heat up and form a bright tail.

Dwarf planets like Pluto are too small to be called full planets but still orbit the Sun.

Key Words

OrbitThe curved path an object takes around another object due to gravity. GravityA force of attraction between all objects with mass. It keeps planets orbiting the Sun. Nuclear FusionA reaction where small atoms join together to make bigger ones, releasing huge amounts of energy. This is how the Sun produces heat and light. AsteroidA small rocky body orbiting the Sun, mostly found between Mars and Jupiter. CometA ball of ice, rock and dust that develops a bright tail when near the Sun. TerrestrialMeans "Earth-like" — rocky planets close to the Sun.

Watch & Learn

These short videos explain the Solar System visually — great for revision.

Crash Course Astronomy #9 — Introduction to the Solar System
12 mins · Click to watch on YouTube
National Geographic — Solar System 101 FreeSchool — Exploring Our Solar System
Foundation

Quick Check — Solar System Basics

1. How many planets are in our solar system?

2. What keeps the planets orbiting the Sun?

3. Which are the 4 rocky planets?

Core

Fill in the Blanks

Use the word bank to complete the sentences.

gravity nuclear fusion asteroid belt gas giants comets

The Sun produces energy through .

The Sun's keeps the planets in orbit.

Most asteroids are found in the between Mars and Jupiter.

Jupiter, Saturn, Uranus and Neptune are known as .

Balls of ice, rock and dust that develop tails near the Sun are called .

Stretch

Stretch Questions

1. What process powers the Sun?

2. Why is Pluto no longer classified as a full planet?

3. Explain why the inner planets are rocky while the outer planets are gaseous.

Day, Night & the Moon

Day and Night

The Earth rotates (spins) on its axis once every 24 hours. The side facing the Sun gets daylight. The side facing away is in darkness (night).

Seasons

The Earth's axis is tilted at 23.5 degrees. As Earth orbits the Sun (which takes 365.25 days — one year), different parts of the Earth are tilted towards or away from the Sun. This causes the seasons.

When the UK is tilted towards the Sun, we get summer (longer days, Sun higher in the sky). When tilted away, we get winter (shorter days, Sun lower in the sky).

Think about it: In summer the Sun is higher and it stays light much longer — that's because your part of Earth is tilted towards the Sun!

The Moon

The Moon orbits the Earth roughly every 28 days. It does not produce its own light — it reflects sunlight.

As the Moon orbits, we see different amounts of its lit side. These are called phases: new moon, crescent, half moon (quarter), gibbous, and full moon.

Key Words

AxisAn imaginary line through the centre of Earth from the North Pole to the South Pole. Earth spins on this line. RotateTo spin around an axis. Earth rotates once every 24 hours. OrbitTo move in a curved path around another object. Earth orbits the Sun in 365.25 days. TiltEarth's axis is not straight up — it leans at 23.5 degrees, which causes the seasons. PhasesThe different shapes of the Moon we see as it orbits Earth (new moon, crescent, quarter, gibbous, full). ReflectWhen light bounces off a surface. The Moon reflects the Sun's light.

Watch & Learn

Crash Course Kids — Earth's Rotation & Revolution
4 mins · Click to watch on YouTube
Vsauce — How Earth Moves Dr Binocs — Phases of the Moon
Foundation

Quick Check — Earth & Space

1. How long does it take Earth to rotate once?

2. What causes the seasons?

3. The Moon produces its own light. True or false?

Core

Put in Order — Moon Phases

Click the phases in the correct order, starting from New Moon.

Half Moon
New Moon
Full Moon
Crescent
Gibbous
1.
2.
3.
4.
5.
Stretch

Stretch Questions — Earth & Space

1. Why do we have leap years?

2. A lunar eclipse occurs when...

3. Why do we always see the same side of the Moon?

Seasons & Earth's Tilt

Why do we have summer and winter? It's NOT because we're closer to the Sun! It's all about Earth's tilt. This section explores exactly how the 23.5° tilt causes our seasons.

Key Facts — Why We Have Seasons

Earth's axis is tilted at 23.5 degrees. This tilt never changes direction — it always points the same way in space.

As Earth orbits the Sun over one year, different parts of Earth are tilted towards or away from the Sun.

Key point: When it's summer in the UK, it's winter in Australia! The seasons are opposite in the Northern and Southern Hemispheres.

Watch & Learn — Seasons Videos

These short videos explain exactly how Earth's tilt causes seasons.

Dr Binocs — Earth's Rotation & Revolution: Why Do We Have Seasons?
6 mins · Click to watch on YouTube
How the Movement of the Earth and Sun Cause the Days, Seasons and Years
2 mins · Click to watch on YouTube

How Tilt Affects Sunlight

It's easy to think summer happens because Earth is closer to the Sun — but that's a common misconception! Earth's orbit is nearly circular, so distance barely changes.

What really matters is the angle of sunlight:

Foundation

Quick Check — Seasons

1. What causes the seasons on Earth?

2. When the UK is tilted towards the Sun, what season is it?

3. At what angle is Earth's axis tilted?

Core

Fill in the Blanks — Seasons & Tilt

Use the word bank to complete the sentences.

23.5 summer towards shorter orbit winter

Earth's axis is tilted at degrees.

It takes one year for Earth to the Sun.

When your hemisphere is tilted the Sun, you experience .

When your hemisphere is tilted away from the Sun, it is and the days are .

Core

Put in Order — Seasons in the UK

Click the seasons in the correct order, starting from the beginning of the year.

Summer (June–August)
Winter (December–February)
Autumn (September–November)
Spring (March–May)
1.
2.
3.
4.
Stretch

Stretch Questions — Seasons

1. Why is the common explanation "Earth is closer to the Sun in summer" incorrect?

2. Why are days longer in summer?

3. What would happen to the seasons if Earth's axis had no tilt (0°)?

Final Quiz — Test Everything!

10 questions covering the Solar System, Earth's tilt, seasons, and the Moon. You get instant feedback on each one.

Tip: Read each question carefully. If you're not sure, eliminate the answers you know are wrong first.

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