8.7

Understand how stars can be classified according to their colour

Different colour stars can be classifed in the hertzsprung-russel diagram, the spetrum of light given out is an indication of how bright they are. Two stars with exactly the same spectrum should be of similar brightness. If one is much dimmer, that is because it is further away. This can be used to estimate the distance of stars.

8.13

describe the past evolution of the universe and the main arguments in favour of the Big Bang 

8.12

draw the main components of the Hertzsprung–Russell diagram (HR diagram) 

8.11

understand how the brightness of a star at a standard distance can be represented using absolute magnitude 

8.10

describe the evolution of stars with a mass larger than the Sun 

8.9

Describe the evolution of stars of similar mass 

to the  Sun through the following stages: 

-nebula 

-star (main sequence) 

-red giant 

-white dwarf

Gravity pulls the dust and gas together

8.8

Know that a star’s colour is related to its surface temperature

The cooler the colour the hottter the star

Stars with surface temperatures up to
3,500 degrees are red
5,000 degrees are orange-red
7,5000 degrees are yellow-white
10,000 degrees are white
30,000 degrees blue-white
60,000 dgrees blue

8.6

Use the relationship between orbital speed, oribital radius and time period

Orbital speed = 2 x pi x orbital speed                         v = 2 x pi x r

                                Time period                                             T

8.4

Explain that gravitational force:

- Causes Moons to orbit planets, as planets has a larger mass than moons, planets have stronger gravitational pull and will attract moons so they orbit the planets.
- Causes the planets to orbit the Sun, as the Sun has a larger mass than planets, the Sun has stronger gravitational pull and will attract planets so they orbit the Sun.
- Causes artifical satellites to orbit the Earth, as the Eartth has a larger mass than artifical satellites, the Earth has more gravitational pull and will attract artifical satellites so they orbit the earth.
- Causes comets to orbit the Sun, as the Sun has a larger mass than comets, the Sun has stronger gravitational pull and will attract comets so they orbit the Earth.

8.3

Undertstand why gravitational field strength, g,varies and know that it is different on other planets and the moon from that on earth

- Gravitational field strength is how strongly something pulls an object towards it

- Planets further away from the sun travel slower because they have lower gravitational pull due to its distance away from the sun.

- There is gravitational pull between all masses.

- Larger masses have bigger gravitational pull.

- Planets with a larger mass have a stronger gravitational field strength, the Earth has a higher gravitational field strength than the moon so on the Earth you can only jump for a few secondsbut you can jump forlongeron the moon as it has a weaker gravitational field

8.5

Describe the difference in the orbits of comets, moons and planets

Moons

-Orbits planets

-Elliptical orbit

-Constant oribtial speed

Planets

-Orbits stars

-Elliptical orbit

-Constant orbitial speed

Comets

-Orbits stars

-Elliptical orbit

-Eccentric oribital speed