Optics
Optics is an area of physics which looks at how light behaves and how we can observe it.
This usually involves using mirrors and lenses to magnify, focus, and direct the path of light.
Waves
We are all familiar with waves; from ripples on the surface of a pond to the swell of the ocean. A wave is just a regular vibration that travels through something, like air or water.
Electromagnetic Spectrum
This light that we see is just one small chunk of light which is made by stars. We often call the small range of wavelengths our eyes can detect, optical, or visible light.
Wave-Particle Duality
Light is complicated as it can act as both a wave and a particle. Choosing how we want to talk about light - wave or particle - is only a matter of convenience.
Spectra
Even though light often looks white, it is made up of lots of different colours all added together.
Light
When we talk about light we usually mean the light we can see with our eyes. This is also called visible or optical light.
Gravitational Lensing
Space is not flat. It is 3D, and we say that everything in it is held together on an imaginary surface we call spacetime. The idea of spacetime was put forward in Einstein's theory of relativity.
