Sunlight is light from the Sun and is also called daylight or visible light.

  • 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.