Solar system, Reflection, Refraction and lenses.

Solar system, Reflection, Refraction and lenses.

1. Models of the Solar System

   • Geocentric
     • Proposed by Ptolemy this model of the solar system shows the earth being the centre of the solar system which everthing revolves round.
     • This is a very complicated and vague representation which doesn't accurately predict placement of planets.
   • Heliocentric
     • This is the model where the sun is in the centre of all the planets and moons orbit the planets. Also that the planets further away from the sun travel slower.
       • This was proven by Galileo when he used a telescope to observe the four moons orbiting Jupiter which proved the heliocentric model wrong.
     • This is the correct model for the configuration of the solar system.

2. Reflection

   • All waves can be reflected
     • Sound waves, Radiowaves and light waves.
   • Light waves
     • The angle of indices (i)is equal to the angle of reflection (r)

3. Refraction

   • Refraction is the bending of light rays at a surface. An example of this is entering or leaving a glass block.
   • Refraction occurs due to the change of speed as it travels through different materials.
     • Less dense to more dense materials means the speed slows down. This causes it to bend towards the normal.
     • More dense to less dense means the speed becomes quicker. This causes it to bend away from the normal.

4. Understanding lenses

   • There are 2 types of lenses
     • Converging
       • Fatter in the middle
       • Used to form images in telescopes
       • Parallel light rays to the principal axis converge on the focal point.
     • Diverging
       • Thinner in the middle