When we look at light reflecting from an object such as a grandfather-clock, we see a time-delayed reflection through a radiation source, a photon. Our brains then process and turn that electromagnetic (EM) radiation into colours. So what our brains see is an interpretative description of electromagnetic radiation. If you are colour blind, you will see shades of grey; this is how matter looks before the human brain processes and adds colour.
So what is electromagnetic radiation? Electromagnetic radiation can be defined as: “Energy resulting from the acceleration of electric charge and the associated electric fields and magnetic fields. The energy can be regarded as waves propagated through space (requiring no supporting medium) involving oscillating electric and magnetic fields at right angles to each other and to the direction of propagation.“Source: Oxford Dictionary of Science, John Daintith, Elizabeth Martin, et al., 2005, Oxford University Press.
Electromagnetic radiation can be seen as a form of heat, and heat can be transferred from one body or system to another by electromagnetic radiation. We measure the amount of heat within any body or system as temperature. Temperature can be seen as a measurement of work, as the hotter something is, the more energy it has. Different forms of electromagnetic radiation are composed of varying forms of electrical charge (eV) and a corresponding frequency (Hz), with an associated wavelength λ in meters (m). Continue reading