Space and Earth
Earth is part of the solar system, and the regular movements of the Earth and Moon create predictable patterns of day and night, seasons, and tides.
What You Need to Know
Key Concept Diagram
Earth rotates on its axis once every 24 hours, causing day and night as different parts face the Sun
Earth orbits the Sun once every 365.25 days; the tilt of Earth's axis causes the seasons
The Moon orbits Earth roughly every 28 days; its changing position relative to the Sun creates lunar phases
Tides are caused by the gravitational pull of the Moon on Earth's oceans
Key Vocabulary
Rotation
The spinning of Earth on its own axis, taking approximately 24 hours
Revolution
The movement of Earth around the Sun, taking approximately 365.25 days (one year)
Lunar phase
The changing shape of the lit portion of the Moon as seen from Earth during its monthly cycle
Axis
An imaginary line through the centre of the Earth, around which it rotates
Knowledge Check
Select 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
Australia experiences summer in December. What is the main cause of seasons?
Question 3
About how long does it take the Moon to complete one full orbit of Earth?
Key Concepts Summary
- ●Earth rotates on its axis once every 24 hours, causing day and night as different parts face the Sun
- ●Earth orbits the Sun once every 365.25 days; the tilt of Earth's axis causes the seasons
- ●The Moon orbits Earth roughly every 28 days; its changing position relative to the Sun creates lunar phases
- ●Tides are caused by the gravitational pull of the Moon on Earth's oceans