S: Energetic Transformations
FC: Energy Transformations by Roshani Shah
1: Georgia Performance Standards | S8P2. Students will be familiar with the forms and transformations of energy. a. Explain energy transformation in terms of the Law of Conservation of Energy. b. Explain the relationship between potential and kinetic energy. c. Compare and contrast the different forms of energy (heat, light, electricity, mechanical motion, sound) and their characteristics. d. Describe how heat can be transferred through matter by the collisions of atoms (conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of heat (convection).
2: The Law of Conservation of Energy The law of conservation of energy is one of the basic laws of physics and therefore governs the microscopic motion of individual atoms in a chemical reaction. The law of conservation energy states: In a closed system, i.e., a system that isolated from its surroundings, the total energy of the system is conserved. So, the law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant. | Energy in a system may take on various forms. 1.Kinetic energy - energy of motion. 2.Potential energy - energy of ``location'' with respect to some reference point. 3.Chemical energy - energy stored in chemical bonds, which can be released in reactions. 4.Electrical energy - energy created by separating charges; energy stored in a battery, for example. 5.Thermal energy - energy given off as heat, such as friction. S8P2. Students will be familiar with the forms and transformations of energy. a.Explain energy transformation in terms of the Law of Conservation of Energy.
4: S8P2. b.Explain the relationship between potential and kinetic energy. Energy can be in one of two states: potential or kinetic. Energy can be transferred from potential to kinetic and between objects. Potential energy is stored energy—energy ready to go. A lawn mower filled with gasoline, a car on top of a hill, and students waiting to go home from school are all examples of potential energy. Water stored behind a dam at a hydroelectric plant has potential energy. Most of the energy under our control is in the form of potential energy. Potential energy can be viewed as motion waiting to happen. When the motion is needed, potential energy can be changed into one of the six forms of kinetic energy. Kinetic energy is energy at work. A lawn mower cutting grass, a car racing down a hill, and students running home from school are examples of kinetic energy. So is the light energy emitted by lamps. Even electrical energy is kinetic energy. Whenever we use energy to do work, it is in the kinetic state.
6: d. Describe how heat can be transferred through matter by the collisions of atoms (conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of heat (convection). Heat is given off when an object's thermal energy is transferred. Thermal energy (see below) can be transferred in three ways: by conduction, by convection, and by radiation. 1. Conduction Conduction is the transfer of energy from one molecule to another. This transfer occurs when molecules hit against each other, similar to a game of pool where one moving ball strikes another, causing the second to move. Conduction takes place in solids, liquids, and gases, but works best in materials that have simple molecules that are located close to each other. For example, metal is a better conductor than wood or plastic. 2. Convection Convection is the movement of heat by a liquid such as water or a gas such as air. The liquid or gas moves from one location to another, carrying heat along with it. This movement of a mass of heated water or air is called a current. 3. Radiation Heat travels from the sun by a process called radiation. Radiation is the transfer of heat by electromagnetic waves. When infrared rays strike a material, the molecules in that material move faster. In addition to the sun, light bulbs, irons, and toasters radiate heat. When we feel heat around these items, however, we are feeling convection heat (warmed air molecules) rather than radiated heat since the heat waves strike and energize surrounding air molecules.