Convex lens - bluges outwards bringing light rays together (converge).
Concave lens - caves inwards causing light rays to spread out (diverge).
Axis - a line passing through the middle of the lens.
Real image - the light from an object comes together to form an image on a 'screen'.
Virtual image - rays diverge to make the object appear to be coming from a completely different place.
Ray Diagram - shows the path a ray travels in. The line is always straight.
Magnifying glass - creates a magnified virtual image.
Opaque - objects that do not transmit light. They absorb some wavelengths and reflect others.
Transparent/translucent - transmit light. Some wavelengths pass through.
Colour filters - only let through particular wavelengths.
Refraction of Light
Watch the video and have a go at writing out the steps of the practical.