Lesson 1 Energy and Society Six Basic Forms of Energy mechanical energy kinetic energy that a body possesses by virtue of its motion examples baseball player pitching a ball a plow being pulled by a tractor a hammer that is being used to pound nails frisbee in the US we use about 1 3 of our total energy for transportation or movement of people and goods mechanical energy potential energy that a body possesses by virtue of its position relative to a reference point examples pendulum a bow archery a spring and a hammer swinging of a golf club earth book system a book sitting on a shelf in the library is said to have potential energy because if it is nudged off gravity will accelerate the book giving the book kinetic energy Because the Earth s gravity is necessary to create this kinetic energy and because this gravity depends on the Earth being present we say that the Earth book system is what really possesses this potential energy and that this energy is converted into kinetic energy as the book falls chemical energy energy locked in the bonds of molecules in the form of microscopic potential energy which exists because of the electric and magnetic forces of attraction exerted between the different parts of each molecule it is the same attractive force involved in thermal vibrations the molecular parts get rearranged in the chemical reactions releasing or adding to this potential energy examples battery burning wood glucose in the body ice cream melting approximately 85 of the energy used in the U S comes from fossil fuels such as coal oil and natural gas all of these fuels store energy in the form of chemical energy and when they are burned fuels release energy in the form of heat or thermal energy thermal or heat energy energy that combines microscopic kinetic and potential energy of the molecules examples hot beverage and boiling water hot tea temperature is really a measure of how much thermal energy something has the higher the temperature the faster the molecules are moving around and or vibrating i e the more kinetic and potential energy the molecules have fuels chemical energy are oftentimes burnt and converted to thermal or heat energy which is then converted to motion in an automobile or electricity hot cup of coffee is said to possess thermal energy or heat energy because it has a combination of kinetic energy its molecules are moving and vibrating and potential energy the molecules have a mutual attraction for one another much the same way that the book on the bookshelf and the Earth have potential energy because they attract each other electrical energy energy created through the movement of electrons among the atoms of matter one of the most useful and versatile forms of energy examples when put into a toaster it can be converted to heat when put into a stereo it is converted into sound when put into an electric bulb it converts into light when put into a motor it converts into motion or movement mechanical energy street light due to its versatility it is in high demand in the US about 40 of the total primary energy used is converted into electricity for various uses all matter is made up of atoms and atoms are made up of smaller particles called protons which have positive charge neutrons which have neutral charge and electrons which are negatively charged the electrons orbit around the nucleus which contains protons and neutrons just like the planets orbit the sun certain metals have electrons that are only loosely attached to their atoms so they can easily be made to move from one atom to another if an electric field is applied to them when those electrons move among the atoms of matter a current of electricity is created nuclear energy energy produced when reactions occur in an atom resulting in some type of structural change in the nuclei fusion occurs when two small nuclei join together to create one large nucleus or particle and during this process energy is released in the form of light and heat An examples in the sun hydrogen nuclei fuse combine together to make helium nuclei which releases energy fission occurs when the nucleus of one big atom splits into two new atoms and during this process a tremendous amount of energy is released in the form of light and heat An example is in a nuclear reactor or the interior of the earth uranium nuclei split apart causing energy to be released in both fusion and fission some of the matter making up the nuclei is converted into energy represented by the famous equation E mc2 Energy Mass x Speed of Light 2 the formula indicates that energy intrinsically stored in matter at rest equals its mass times the speed of light squared When matter is destroyed the energy stored is released suggests that an incredibly huge amount of energy is released when a small amount of matter is converted to energy radiation energy energy radiated or transmitted into the form of rays waves or particles examples visible light that can be seen by naked eye infrared radiation ultraviolet radiation UV that cannot be seen with the naked eye long wave radiation such as TV waves and radio waves very short waves such as x rays and gamma rays sun electromagnetic radiation energy from the sun comes to the earth in the form of electromagnetic radiation which is a type of energy that oscillates side to side and is coupled with electric and magnetic fields that travel freely through space electromagnetic radiation is composed of photons or particles of light which are sometimes referred to as packets of energy photons created when electrons jump to lower energy levels in atoms and absorbed when electrons jump to higher levels are also created when a charged particle such as an electron or proton is accelerated An example of this is a radio transmitter antenna that generates radio waves electromagnetic spectrum photons are associated with visible light which accounts of only a very limited representation of the wide range of wavelengths of electromagnetic radiation part of the electromagnetic spectrum a great discovery of the nineteenth century was that radio waves x rays and gamma rays are just forms of light and that light is electromagnetic waves lower the energy the longer the wavelength and lower the frequency LLL sunlight can hurt your skin and eyes because it contains UV light which consists of high energy photons They have short wavelengths and high frequencies and pack enough energy in each photon to cause physical damage to your skin radio waves