Syllabus Aims…
8.2 know that:
- the universe is a large collection of billions of galaxies
- a galaxy is a large collection of billions of stars
- our solar system is in the Milky Way galaxy.
8.3 understand why gravitational field strength, g, and know that it is different on other planets and the Moon from that on the Earth
8.4 explain that gravitational force:
- causes moons to orbit planets
- causes the planets to orbit the Sun
- causes artificial satellites to orbit the Earth
- causes comets to orbit the Sun
8.5 describe the differences in the orbits of comets, moons and planets
8.6 use the relationship between orbital speed, orbital radius and time period:
orbital speed = (2 × π × orbital radius)/time period
v=2rπ/T
Resources…
Use these PowerPoint for a quick review..
- Lesson 1 Days Years and Seasons
- Lesson 2a 2b Phases of the Moon and Eclipse
- Lesson 3a 3b Gravitational Forces and Orbits
- 8 Astrophysics Part B Orbits
Further Resources….
- Speed of Light Calc
- Graphs for Solar System
- Arrokoth the most distant object ever visited (Wider Reading)
- Voyager 2 Back Online (Wider Reading)
- Investigating circular motion Practical
- Investigating circular motion Practical Results
- Lesson 2 Maths Challenge Worksheet
- Lesson 2 Orbits Exam Questions
- Gravitational Force F=ma extra help video
- Gravitational Fields g =GM/r^2 extra help extension video
- Circular Velocity v= 2πr/T extra help video
- iPad QR Code Reader
- Android QR Code Reader
Useful Videos…
The Four Seasons Using a Tilting Planet Model
We have 4 seasons due to the tile of the Earth at 23.5 degrees. Sometimes the Northern hemisphere points towards the sun in the summer and sometimes away in the winter.Show More

The Four Seasons Using a Tilting Planet Model
We have 4 seasons due to the tile of the Earth at 23.5 degrees. Sometimes [...]

Eclipse of the Moon

Orbital Speed of Planets - GCSE Physics
You can find the orbital speed of a planet if you know its orbital radius [...]

Kepler’s First Law of Motion - Elliptical Orbits (Astronomy)
With his first law of planetary motion, Kepler rejected circular orbits and [...]

Measuring the Universe
The vast size of the universe requires special units when measuring [...]

Q1 8B Astro June 2018 iGCSE Physics
This is a quick video walkthrough of an Edexcel exam question. It is [...]