Photons represent the strange quantum nature of light and all other electromagnetic radiation. For a long time, scientists thought light was only a continuous flowing wave. We now know that light also acts like a stream of individual energy packets called photons.
The amount of energy in a single photon is described by the equation E = hν. In this famous formula, h stands for Planck’s constant and the Greek letter nu represents frequency. You can also calculate the energy using the physical wavelength of the traveling light.
A photon with a shorter wavelength packs a much higher amount of physical energy. In chemistry, photons are absolutely fundamental to the study of spectroscopy and photochemistry. Molecules can absorb photons, but only if the photon energy perfectly matches an internal energy gap.
When a molecule swallows a matching photon, its electrons jump up to a higher energy level. This absorbed energy can cause the molecule to change color, glow, or even break chemical bonds. A common misconception is that a photon is a regular physical object like a marble. In reality, it is a massless bundle of energy that only exists while moving.