Radiation is the transmission of energy in the form of waves or particles including radio waves, microwaves, visible light, x-rays, and gamma radiation. Though the sun produces radiation over a wide swath of wavelengths (and therefore energies), the relative amount of radiation produced in each portion of the electromagnetic spectrum is not equal. For instance, about half of the energy reaches earth in the narrow band we call the visible spectrum, while only about a tenth arrives as ultraviolet (UV) radiation. Once this barrage of energy reaches the earth (eight minutes after leaving the sun’s surface) it is further modified through absorption by the various molecules that make up our atmosphere.
Which wavelengths get absorbed, and by which molecules, is determined by the energy levels of the photons (the smaller the wavelength the greater the energy), and the atomic structure of the molecule, particularly the number and arrangement of its electrons. When a compatible combination of matter and photonic energy comes into contact, the energy from the photon is absorbed and converted to other forms of energy such as thermal or kinetic energy. This energy is often quickly re-emitted as radiation of a different wavelength.
Electromagnetic radiation plays a critical role in almost every aspect of life on earth, from powering photosynthesis to destroying DNA. It is therefore important to understand which wavelengths are absorbed by which materials. As you place the various materials on the board, be sure to read the information provided about that substance and its role in our environment.