Unit E: Electrical Applications Chapter 11: Electrical Energy 11.1: Generating Electricity pg. 420 Key Concepts: 1. Electrical energy is generated using a variety of technologies. 2. Electrical energy is generated using both renewable and non-renewable sources. Electrical Charge: a type of energy that comes from the flow of charged particles; it allows electrical devices to function. Energy can take on many forms, chemical, thermal, electrical, mechanical, and sound energy. When an object can change its environment, it is said to have energy. Energy allows an object to do a task, when form of energy, electrical energy is the movement of charged particles. See Table 1: Common Forms of Energy Form of Energy Chemical Thermal Sound Radiant (light) Mechanical Electrical Examples Gasoline, food, fireworks Warmth from a fire Voices, music Sunlight microwaves Wind, running water Lightning, electricity for your home
Energy Transformations Energy can be transformed into many forms, one form into another form. Table 2: Examples of Energy Transformations Example Energy Transformation Solar panel Light energy electrical energy Fire Chemical energy thermal energy and light energy Wind turbine Mechanical energy electrical energy Car engine Chemical energy thermal energy mechanical energy Light bulb Electrical energy thermal energy and light energy Generating Electrical Energy The Grid: Electrical Energy Distribution Grid: a network that carries electricity from the energy generating station to the consumer. Some electrical energy we use is provided by batteries, most is provided by the Electrical Energy Distribution Grid, also known as the power grid. Most of our electrical devices run off the power grid as we plug them into a socket in the wall.
Generators Generator: a device that produces electricity by rotating a wire coil near a magnet. A generator is a machine that converts mechanical energy into electrical energy, at electrical generating stations. A basic generator consists of a magnet and a wire coil. The north and south poles of a magnet can create a push or a pull. When the coil rotates near the poles (north/south) the negatively charged particles in the wire are forced to move. The faster the coils rotate the more electricity is produced. Figure 3: Falling water or another source of mechanical energy spins a turbine that, in turn spins coil of wire between magnets to generate electrical energy. The flow of water, or steam and wind can be converted into electrical energy. These are used to turn a turbine, which is connected to the wire coils inside the generator. As the turbine spins, so does the coil.
Figure 4: Some electrical energy stations use the movement of flowing water to generate electrical energy. Measuring Electrical Energy Kilowatt: 1000 watts. Kilowatt Hour: a unit of energy equal to using 1000 W for 1 h. All energy is measured in the unit of joules (J). The production or use of electrical energy is measured as the number of joules per second. A joule per second is called a watt (W). The higher the wattage of an electrical device the more energy is used per second. Therefore a fluorescent light uses 20 J per second, is said to be a 20 W bulb. A Joule is a small unit of measure, so a larger unit of measure is used, Kilowatt (kw). Kilowatt is measured, as a 1000 watts per hour.
Check Your Learning: Questions 1 5, pg. 423 Wrap Up: - There are various forms of energy; light, chemical, thermal, mechanical, sound, electrical. One form of energy can be transformed into other forms of energy. - Electrical energy comes from the flow of charged particles. - A generator is a machine that converts mechanical energy into electrical energy. - Wind, steam, and running water are all commonly used to supply the motion needed to produce electricity. Try This: Observing Energy Changes pg. 421
11.1: Generating Electricity pg. 420 Table 1: Common Forms of Energy Form of Energy Chemical Thermal Sound Radiant (light) Mechanical Electrical Examples Gasoline, food, fireworks Warmth from a fire Voices, music Sunlight microwaves Wind, running water Lightning, electricity for your home Table 2: Examples of Energy Transformations Example Energy Transformation Solar panel Light energy electrical energy Fire Chemical energy thermal energy and light energy Wind turbine Mechanical energy electrical energy Car engine Chemical energy thermal energy mechanical energy Light bulb Electrical energy thermal energy and light energy Figure 3: Falling water or another source of mechanical energy spins a turbine that, in turn spins coil of wire between magnets to generate electrical energy Figure 4: Some electrical energy stations use the movement of flowing water to generate electrical energy.