Def: Light is a form of energy.

 

This is proved when Crookes radiometer converts light energy to kinetic energy.

 

My	Mercury
Very	Venus
Easy	Earth
Method	Mars

Just	Jupiter
Speeds	Saturn
Up	Uranus
Naming Planets	Neptune Pluto

 

 

 

 

Def: A group of stars held together by gravitational forces is called a galaxy.

	Our galaxy is called the milky way
	It takes the earth 365.25 days to orbit the sun.

 

Def: The sun and the nine planets that orbit around it make up the solar system.

 

Eclipses occur because light travels in straight lines.

 

Def: A solar eclipse (eclipse of the sun) occurs when the moon comes between the sun and the earth.

 

Def: A lunar eclipse occurs when the moon is in the earths shadow.

 

	It takes the moon 28 days to orbit the earth.
	Umbra = Total eclipse
	Penumbra = Partial eclipse

 

Def: Refraction is the bending of light when it travels from one transparent substance into another. 

Def: The breaking up of white light into different colours is called dispersion.

 

·        Newtons disc: is a disc with seven colours painted on it, when the disc spins quickly it appears to be white.

 

Def: The primary colours of light are red, blue and green.

Def: The secondary colours of light are cyan (turquoise), yellow and magenta.

Def: Complimentary colours are a primary and a secondary colour that together give white.

 

·        All waves in the electromagnetic spectrum all travel at the same speed = 3x10(to the power of 8)

·        UHF= Ultra High Frequency

·        VHF= Very High Frequency

·        One problem of high frequency waves is that they have short wavelengths, so do not bend around obstacles such as hills. = Poor TV reception