- Sunlight is only one form of electromagnetic radiation emitted by the Sun.
- Sunlight is the form of electromagnetic radiation that our eyes are sensitive to.
- Other types of electromagnetic radiation that we are sensitive to, but cannot see, are infrared radiation that we feel as heat and ultraviolet radiation that causes sunburn.
- The electromagnetic spectrum includes all possible wavelengths of electromagnetic radiation, ranging from low energy radio waves through visible light up to high energy gamma rays.
- Sunlight is only a very small part of the electromagnetic spectrum.
- The visible part of the electromagnetic spectrum is called the visible spectrum.
- The human eye is tuned to the visible spectrum and so to spectral colours between red and violet.
- All forms of electromagnetic radiation can be described in terms of both waves or particles.
- All forms of electromagnetic radiation travel at 299,792 kilometres per second in a vacuum.