Outline the phases of the Moon. Describe how eclipses occur.
Distinguish between solar and lunar eclipses.
The Moon orbits the Earth once every 27 days. It also rotates on its own axis once every 27 days.
The Moon is smaller than the Earth, so its gravitational field is less. Its gravity is one-sixth that of the Earth’s gravity.
As the gravity on the Moon is less, all gas particles have escaped. This means that the Moon does not have an atmosphere.
The Moon is covered in craters that are believed to have been caused by large rocks from space crashing onto its surface.
z Fig. 23.2.1
The surface of the Moon
It is important to remember: z z
zz zz
Examining craters
Plan, design, carry out and write up an investigation to find out what factors change the size and shape of a crater formed when an object, for example a rock or a ball, falls onto a surface such as sand or flour.
Moons orbit planets
Planets orbit stars. The Sun is a star. Moons orbit planets.
Moons, planets and stars all rotate around their axes. Planets orbit a star
z 404 404
Fig. 23.2.2 How the Earth, Sun and Moon orbit and rotate
