Energy: Forms and Transformations

Energy Vs force? A force is a push or pull. It is the result of the interaction between two objects. Energy causes or gives something the ability to change or cause motion. A force can only occur if energy is present. They both can be transferred to objects.

What is Energy? the ability to make things move or change Energy can exist as either Kinetic Energy or Potential Energy (energy of Motion) (stored energy)

What are the various forms of Energy? Chemical Sound Solar Electrical Mechanical Magnetic Thermal Nuclear

Electromagnetic Energy Energy that can be reflected or emitted from objects through electrical or magnetic waves traveling through space. (Radio & TV waves, cell phone, microwaves, light wave) Electrical Energy Electrical energy is the movement of electrons generally through a wire. Lightning and static electricity are examples of electrical energy that occur naturally.

Thermal/ Heat Energy Elastic Energy Thermal energy is energy that comes from heat due to the random motion of molecules, atoms and particles in a substance. Elastic Energy Elastic energy is stored energy in expanded (stretched) or compressed (squashed) objects.

Chemical Energy Sound Energy Chemical Energy is energy stored in the bonds of chemical compounds (atoms and molecules). Chemical energy is released in a chemical reaction, often in the form of heat. Such reactions are called exothermic. Batteries, biomass (food), petroleum, natural gas, and coal are examples of stored chemical energy Sound Energy Sound is the movement of energy through substances in longitudinal waves. Alarms, music speech all use sound energy.

Nuclear Energy Gravitational Energy Nuclear energy is the energy stored in the nucleus of an atom. Nuclear energy is unusual in that it can give off energy in the form of light or heat, but it is the change in the atom's makeup that produces the energy. Submarines, power plants, and smoke detectors all use nuclear energy. Nuclear power plants use uranium, a radioactive element, to create electricity. Gravitational Energy Gravitational energy is stored energy in raised objects. It is the result of an objects position relative to the earth or another object.

Magnetic Energy Mechanical Energy Magnetic energy is the attraction of objects made of iron. Compass, refrigerator magnets use magnetic energy. Any type of energy source that uses a generator in the process to make electricity uses magnetic energy. Mechanical Energy Mechanical energy is due to an objects motion or position. Therefore it is the total amount of kinetic and potential energy in a system. Wind-up toys and grandfather clocks are examples of mechanical energy.

All forms of energy falls under two categories: POTENTIAL Stored energy and the energy of position (gravitational). KINETIC The motion of waves, electrons, atoms, molecules, and substances. Electromagnetic energy THERMAL ENERGY or heat The vibration or movement of atoms and molecules in substances. CHEMICAL ENERGY stored in the bonds of atoms and molecules. NUCLEAR ENERGY stored in the nucleus of an atom MECHANICAL ENERGY movement of parts or a substance from one place to another. SOUND movement of energy through longitudinal waves. ELECTRICAL ENERGY is the movement of electrons. Law of Conservation of Energy ELASTIC ENERGY stored in the compression and stretched of an object GRAVITATIONAL ENERGY energy of place or position. MAGNETIC ENERGY energy stored in magnetic fields

Describe the process of energy transfer. Energy transfer happens when energy moves from one object to another. Example: When the golfer swings a golf club, the moving club has mechanical energy. When the club hits a golf ball, some of the energy of the club is transferred to the ball, causing the ball to move.

Energy Transfer Tree. PE KE PE KE PE PE Gravitational energy Mechanical energy PE Elastic energy Sound energy Sound energy PE Heat energy

PE K PE PE As the ball falls it speeds up causing the transformation of PE to KE. As the ball goes up gravity slows it down causing the transformation of KE to PE. KE KE KE

What is energy transformation? This occurs when energy changes from one form to another This allows us to use energy in different ways Examples: Green plants transform electromagnetic energy into forms of sunlight into food. The food is stored chemical energy A flashlight changes chemical energy stored in a battery into electrical energy and then into light and heat.

What is the Law of Conservation of Energy Energy is not created or destroyed. It changes from one form to another. The amount of energy before the transfer is always equal to the amount of energy after the transfer. Transfer of energy from one object to another is never 100% Energy that is not useful in the transfer is released into the environment as heat, light, sound, etc…

Law of Conservation of Energy Chemical energy in the battery is transformed into electrical energy which is carried through wires to the light bulb where it is transformed into light energy. Heat energy is also produce but is released into the environment

What is the relationship between solar energy and photovoltaic cells?

What is the relationship between solar energy and photovoltaic cells? Solar energy is the radiant energy produced by the Sun. It is the result of movement of photons and electrons in electromagnetic radiation. Photovoltaic cell is a device that can change light energy into electricity it is also called solar cell. Photovoltaic cell are used in solar energy production