When you spend time outside in sunlight, you may wear a hat or long sleeves or sunscreen. Why do you take those precautions? You may know that overexposure to sunlight can be harmful to your health, but did you also know that exposure to sunlight is important for your health? Sunlight consists of different types of radiation including ultraviolet (UV) radiation that activates a precursor in your skin that is converted, through a metabolic pathway in your body, to the active form of Vitamin D. Vitamin D helps your body absorb calcium and is needed for strong bones. Overexposure to this UV radiation, however, can lead to skin cancer.
Radiation is the emission of energy from some source through space as particles or electromagnetic waves. UV radiation is a form of electromagnetic radiation emitted by the sun and the energy of the sun is produced by a nuclear reaction known as fusion. We will discuss both types of radiation as we explore nuclear chemistry and continue to develop the model of the atom.