Level: JHS, Basic 8 | Subject: Integrated Science | Strand: Systems | Topic: The Solar System (Outer Planets)
Curriculum reference: B8.3.2.1 Demonstrate knowledge of the outer planets of the solar system. Indicator B8.3.2.1.1: Identify the outer planets (gas giants) and describe their properties. All the exemplars are merged into one set of notes.
1. The Outer Planets
The solar system has eight planets going round the Sun. The four inner planets are Mercury, Venus, Earth and Mars. The four outer planets lie beyond the asteroid belt. They are Jupiter, Saturn, Uranus and Neptune. The first two are called gas giants. Uranus and Neptune are called ice giants because they have a lot of frozen water, ammonia and methane.
Memory aid for the order from the Sun: Jupiter, Saturn, Uranus, Neptune. Together with the inner planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
2. Properties of Each Outer Planet
| Planet | Key facts |
|---|---|
| Jupiter | The largest planet. Made mostly of hydrogen and helium. Has a Great Red Spot, which is a huge storm. Has many moons. |
| Saturn | Second largest. Famous for its bright rings made of ice and rock. Very light for its size. |
| Uranus | Looks blue-green because of methane. It spins on its side. Very cold. |
| Neptune | The farthest planet from the Sun. Deep blue. Very cold and windy. |
3. Comparing Inner and Outer Planets
| Feature | Inner planets | Outer planets |
|---|---|---|
| Size | Small | Very large |
| Make-up | Rock and metal (solid surface) | Mostly gas and ice (no solid surface to stand on) |
| Distance from the Sun | Near | Far |
| Temperature | Warmer | Very cold |
| Moons | Few or none | Many |
| Rings | None | All four have rings, Saturn’s are the brightest |
| Time for one orbit of the Sun | Short | Very long |
4. Why Do Outer Planets Take Longer to Orbit?
They are far from the Sun, so their path is very long. Also, the pull of the Sun is weaker there, so they move more slowly. Jupiter takes about 12 Earth years to go round the Sun once. Neptune takes about 165 Earth years.
5. Other Members of the Solar System
- Moons go round planets.
- The asteroid belt lies between Mars and Jupiter.
- Comets are balls of ice and dust with long paths.
- Dwarf planets such as Pluto are small and round, but they are not planets.
Remember: Outer planets are big, cold and far from the Sun. Inner planets are small, rocky and warm.
Ready to practise?
Education Always (education.inspiringalways.com). Original notes written to follow the NaCCA Basic 8 Integrated Science curriculum.