Year 5 Science: The Sun and the planets
Part of the Year 5 Science the earth, sun and moon chapter. Chapter overview · whole chapter on one page
The Sun and the planets
The solar system is made of the Sun, and the planets and other objects that move round it. The Sun is a star. It is at the centre of the solar system.
The planets move round the Sun along paths called orbits. The Earth is the third planet from the Sun. There are eight planets in the solar system, in this order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
The Earth takes about 365 days to go once round the Sun. This is one year.
| Planet | Order from the Sun |
|---|---|
| Mercury | 1 |
| Venus | 2 |
| Earth | 3 |
| Mars | 4 |
| Planet | Days to go once round the Sun |
|---|---|
| Mercury | 88 |
| Venus | 225 |
| Earth | 365 |
| Mars | 687 |
Key ideas
- The Sun is at the centre of the solar system.
- The planets move round the Sun along paths called orbits.
- There are eight planets. The Earth is the third planet from the Sun.
- The Earth takes about 365 days to go once round the Sun.
Method. Find the smallest number of days.
- Read the table. Mercury takes 88 days, which is the fewest in the table.88 days
- Name the planet. So the planet is Mercury.Mercury
- Write the answer. Mercury
Check. Mercury is the closest planet to the Sun. ✓
Method. Count the planets from the Sun.
- Count from the Sun. Mercury is first, Venus is second, and the Earth is third.third
- Name the planet. The third planet from the Sun is the Earth.Earth
- Write the answer. Earth
Check. The Earth is the third planet from the Sun. ✓
Method. Subtract the Earth’s days from the Mars days.
- Read the two numbers. Mars takes 687 days, and the Earth takes 365 days.687 and 365
- Subtract. The difference is 687 minus 365, which is 322.687 - 365 = 322
- Write the answer. 322
Check. Check: 365 + 322 = 687. ✓
Watch out. Subtract the smaller number from the larger one.
Watch out
Watch out: the planets do not stay still while they go round the Sun. They are always moving along their orbits.
Try it (with your teacher). Ask your teacher to show a model of the solar system, or a globe with a ball in the middle. Use a torch as the Sun, and a small ball as the Earth. Move the ball slowly round the torch, in a circle, and say which way it moves. Never look straight at the Sun.
Exam tip
Grown-up tip. Ask: “What is in the middle of the solar system? Which planet is the Earth? What does the Earth go round?” Keep the talk factual and calm.
Exercise 8A The Sun and the planets
Method. Read the key ideas in section 8.1.
- Read the key idea. The Sun is at the centre of the solar system.centre
- Name it. So the answer is the Sun.Sun
- Write the answer. Sun
Check. The planets move round the Sun. ✓
Method. Read section 8.1.
- Read the definition. The planets move round the Sun along paths called orbits.paths called orbits
- Name it. The word is orbit.orbit
- Write the answer. orbit
Check. An orbit is the path of a planet round the Sun. ✓
Method. Read the list of planets in section 8.1.
- Read the list. The list has Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.eight names
- Count them. So there are eight planets.8
- Write the answer. 8
Check. Count the names in the list carefully. ✓
Method. Count the planets from the Sun.
- Count. Mercury is first, Venus is second, and the Earth is third.third
- Name it. So the third planet is the Earth.Earth
- Write the answer. Earth
Check. The Earth is the third planet from the Sun. ✓
Method. Read the order of the planets.
- Read the order. Mercury is first in the order from the Sun.first
- Name it. So Mercury is the closest planet to the Sun.Mercury
- Write the answer. Mercury
Check. Mercury is the first planet from the Sun. ✓
Method. Read the order table.
- Read the table. The second row in the order table is Venus.Venus
- Name it. So Venus is second from the Sun.Venus
- Write the answer. Venus
Check. The order table lists the first four planets. ✓
| Planet | Days to go once round the Sun |
|---|---|
| Mercury | 88 |
| Venus | 225 |
| Earth | 365 |
| Mars | 687 |
Method. Read the row for the Earth.
- Read the row. The Earth row shows 365 days.365
- Write the number. So the Earth takes 365 days.365
- Write the answer. 365
Check. This is about one year. ✓
| Planet | Days to go once round the Sun |
|---|---|
| Mercury | 88 |
| Venus | 225 |
| Earth | 365 |
| Mars | 687 |
Method. Find the row with 687.
- Find the row. The row with 687 days is Mars.687
- Name the planet. So the planet is Mars.Mars
- Write the answer. Mars
Check. Mars takes longer than the Earth to orbit the Sun. ✓
| Planet | Days to go once round the Sun |
|---|---|
| Mercury | 88 |
| Venus | 225 |
| Earth | 365 |
| Mars | 687 |
Method. Subtract the Mercury days from the Venus days.
- Read the two numbers. Venus takes 225 days, and Mercury takes 88 days.225 and 88
- Subtract. The difference is 225 minus 88, which is 137.225 - 88 = 137
- Write the answer. 137
Check. Check: 88 + 137 = 225. ✓
Method. Think about the Sun and the planets.
- Think about the Sun. The Sun pulls on the planets.pulls
- Write the reason. So the planets keep moving along orbits round the Sun.orbits round the Sun
- Write the answer. Accept any sentence that says the planets are pulled by the Sun, so they keep moving in orbits round it.
Check. Gravity from the Sun keeps the planets in orbit. ✓
Method. Look for planets after the Earth in the order.
- Find the order. Planets after the Earth are further from the Sun.after the Earth
- Name one. Mars is the next planet after the Earth.Mars
- Write the answer. Accept any one of: Mars, Jupiter, Saturn, Uranus, Neptune.
Check. Any planet after the Earth in the order is further from the Sun. ✓
Method. Think about what a year is.
- Think about the orbit. The Earth takes about 365 days to go once round the Sun.365 days
- Write the reason. That time is one year, so a year is the time of one orbit.one orbit
- Write the answer. Accept any sentence that says the Earth takes about 365 days to go once round the Sun, which is one year.
Check. A year is one orbit of the Earth round the Sun. ✓