Radiation is a scary term that most people have heard of in the form of dangerous X-rays or nuclear radiation but not all radiation is harmful. The sun transfers energy to plants through light which is a form of radiation. But other parts of the light, or radiation, from the sun, the U-V rays, sunburn us. So the radiation from the sun has both good and bad forms. Microwaves use radiation to heat and cook our foods. Heat from a fire place reaches us through radiation. Some forms of radiation are both helpful and harmful. X-rays help us determine what is wrong with people and gamma rays are used to kill cancer cells but to much of these forms of radiation can make people even sicker and even kill them. Though the term radiation is often thought of by many people as an unwanted form of energy, it is essential to our lives. Without the radiation from the sun, plants would dies and animals, including humans, would have nothing to eat. Depending on it form and intensity, radiation can be either a helpful or harmful form of energy; there are benefits and problems with radiation but it is still essential.
Radiation is merely energy that is given off in the form of waves or small particles of matter. Radiation is present whenever there is a transfer of energy and there are two types of radiation: electromagnetic radiation and particle radiation. To completely understand an atom, we must understand it parts but also what it can produce and do.
Electromagnetic Radiation
Light is electromagnetic radiation; it is merely an electric field and a magnetic field that are constantly changing. These changing fields work together to produce energy in the form called electromagnetic radiation. Electromagnetic radiation travels in the form of a wave, The amount of energy that is traveling determines the properties of the waves. But along with being a wave, electromagnetic radiation has particle like properties. Atoms release electromagnetic radiation when their electrons can orbitals. The radiation they release is i small packets called photons. The photons are like a really really tiny particle that has a specific amount of energy in it. The photons have momentum like a particle though they have no mass and travel like a wave. Like waves, the energy of each photon determines the photon's wavelength and frequency (the wave properties). A high frequency photon has a small wavelength and high energy (the opposite is also true). Radiation is classified by its wavelength (and thus its energy) in an arrangement called the electromagnetic spectrum. Gamma rays, X rays, ultraviolet rays, visible light, infrared rays, microwaves, and radio waves is a list of the electromagnetic spectrum. Gamma rays are the highest in energy (smallest wavelength) to radio waves which have the least amount of energy (largest wavelength). Lasers are a good example of electromagnetic radiation at work. By adding together a lot of visible light, a high energy beam can be used to burn through things but also to read our CDs (a less intense laser).
Particle Radiation
Particle Radiation has both properties of particles and waves. It is the movement of a proton, neutron, or electron that travels like a wave, with a defined wavelength, frequency, and speed. There are four types of particle radiation: alpha particles (two protons and two neutrons), beta particles (electrons), protons, and neutrons. Particle radiation often comes from the radioactive decay of an atom. Radioactive atoms spontaneously release radiation (particle radiation) to take on a different form. Atoms can change their nuclear composition by taking in or giving off particle radiation; this changes the number of protons, electrons, and/or neutrons in the atom and thus changes what the atom is. Atoms decay until they reach a stable form and then they are no longer radioactive. The length of time it takes for a half a sample atoms to decay to their new form is known as the atom's half-life. (For an activity to help understand half-life, click here). The half-life of atoms is used to date artifacts found in archeological studies. Radioactivity and particle radiation is an important topic in Atomic Theory. We must understand what a nucleus can do and how it affects us along with understanding how it is made.
For more uses of radiation, both electromagnetic
and particle, check out this webpage
created by The Discovery Channel.