ENERGY Generator. Carlo Waldfried Edited by Anne Starace. Abstract. Keywords: energy, conservation of energy, generator

Transcription

1 ENERGY Generator Carlo Waldfried Edited by Anne Starace Abstract Energy is an important concept in our everyday lives. This module discusses different forms of energy and demonstrates how energy can be transformed from kinetic energy to another form of energy such as heat. Keywords: energy, conservation of energy, generator Funded by the National Science Foundation and the University of Nebraska

2 Content Standards K History & Process Standards K Skills Used/Developed: 2

3 TABLE OF CONTENTS I. OBJECTIVES...4 II. SAFTEY...4 III. LEVEL, TIME REQUIRED AND NUMBER OF PARTICIPANTS...4 IV. LIST OF MATERIALS...4 V. INTRODUCTION...5 VI. PROCEDURE...6 VII. FREQUENTLY ASKED QUIESTIONS..10 VIII. TROUBLE SHOOTING..10 IX. HANDOUT MASTERS.10 X. REFERENCES. 10 3

4 I. OBJECTIVES Students will: -be able to give examples of and differentiate between kinetic, potential, chemical, and thermal energy. -be able to explain the principle of conservation of energy. II. SAFTEY Do not touch both ends of the wires hooked up to the generator while the handle on the generator is being turned. If the wires are connected only to each other while the generator handle is being turned they will get very hot, very quickly. III. LEVEL, TIME REQUIRED AND NUMBER OF PARTICIPANTS LEVEL This activity is appropriate for grades K-12. TIME REQURED Preparation takes only a few minutes and involves getting out the equipment and clamping the generator to the table. This activity takes from minutes to complete. NUMBER OF PARTICIPANTS About 3-10 participants at a time generator kit generator light bulbs heating pad motor patch cords(insulated wire) IV. LIST OF MATERIALS clamps 4

5 V. INTRODUCTION Our world is under constant change, which is possible because there is energy available to be used in making the change. Without energy, the world would be completely static -- no changes could occur. This module explains the different forms of energy and how they can be used to affect change. The principle forms of energy can be categorized as: kinetic energy potential energy chemical energy heat (thermal) energy Although you cannot create or destroy energy (we say that energy is conserved ), energy can be transformed from one type of energy into another type. One of the important characteristics of energy is that it can be used to do work. Work is defined as force multiplied by distance. So basically, moving things is doing work; you must apply a force to make them move a certain distance. The harder you push and/or the farther you move something, the more work you are doing. Often, you cannot actually see energy, but you can measure energy by its ability to do work. The different types of energy have different features and to understand changes between these forms, we have to understand how each type of energy is different than the others. Type of energy description example kinetic energy energy of motion a moving car, a jogger potential energy energy of position: something that could potentially be pulled by gravity a piledriver, a bungee jumper just before the jump, a ball tossed into the air heat or thermal energy energy due to temperature boiling water chemical energy energy stored in chemicals a battery, gasoline, food solar energy energy due to the sun solar cells Energy is constantly being transformed from one form of energy to another. For example, the human body uses food (which contains chemical energy) and converts it in our body into heat (body temperature), kinetic energy (motion), or into a different type of chemical energy - fat. The principle of conservation of energy is the most fundamental principle in the world. Its applications and usages are so common to our everyday life, that often it is not perceived. This module will help participants discover and explore various forms of energy and how they interact. 5

6 VI. PROCEDURE The Generator Setup: 1. Unpack the generator board and mount the assembly on the corner of a table. 2. Secure the assembly with C-clamps to the table top. 3. The kit should contain 4 magnetic elements that can be placed on the magnet pad of the generator assembly: a heating pad, two light bulbs mounted in their sockets and a motor with a pulley and a weight. Be sure to connect red wires (with alligator clips) with red and black with black. wires Motor TABLE Generator Pulley C-Clamp Weight Note: there is only one c-clamp in this picture, but you may need to use two. 6

7 Here is a picture of the generator hooked up to one light bulb. Note that the clamp has been removed to make it easier to see. kinetic energy light and heat a) Connect the wires of the generator to the light bulb assembly. b) When the handle of the generator is turned the light bulb(s) will glow. Notice that the brightness depends on how fast you turn the handle of the generator. c) The kinetic energy (turning to the handle) is being converted into light and heat (given off by the light bulb). d) Now connect two light bulbs in series and parallel and explore the difference between the two configurations. 7

8 Note that wire must touch the bulb at the side and bottom as shown in the picture above. However, the bulbs in the kit may be placed in light bulb holders, which ensure that the current gets to the side and bottom of the bulb. 8

9 kinetic energy heat d) Disconnect the wires from the two light bulbs. e) Connect the generator wires to the heating pad. When turning the generator handle the heating pad will warm up, which is visible due to a color change. You can also touch the heating pad to feel the temperature rise. Notice also that the faster the handle is turning the faster the temperature is rising. Don t worry; the heating pad will not become dangerously hot. kinetic energy kinetic energy and potential energy f) Disconnect the generator wires from the heating pad. g) Finally connect the generator wires to the motor. Make sure that one end of the string is secured through the hole in the pulley and connected the other end of the string to the weight. When the generator is operated by turning the handle, the motor will rotate and pull the weight upwards. h) This time the kinetic energy of the moving handle is being converted into another kinetic energy (the movement of the motor) and increases the potential energy of the weight (the farther from the ground an object is, the more potential energy it has). Cleanup: Return everything to the generator box Dispose of burned out light bulbs. 9

10 VII. Frequently Asked Questions Why do the wires from the running generator get hot when they are connected to only each other? When the generator is running, it sends a flow of electrons out one of the wires. When the wires are attached to apparatuses such as light bulbs, heat pads, or motors, as we saw, the electrons flow out of the wires and into the apparatus where the energy of the moving electrons is converted into another sort of energy. When the wires are hooked up to only each other, the electrons just flow around and around the wires because they have no where else to go. This flow of electrons produces heat. The same thing happens when you attach a wire from one end of a battery to the other: the electrons move through the wire, making it hot and expending the battery. Why can I not touch the ends of the wires from the generator while it is running? As mentioned in the previous answer, when the generator is running, electrons are flowing through the wires. If you touch the uninsulated end of the wire, the electrons will flow from the wire into you! The generator in this kit does not produce enough electricity to cause serious injury, but touching uninsulated, live (with electrons flowing through them) wires is something the students should learn not to do. Can the generator power other things? Yes, the generator used in this module can power things that do not need much electricity to operate. VIII. Trouble Shooting The light bulb does not light up Make sure the wires are connected red to red and black to black. Turn the handle on the generator faster. If it still does not work, try using a different light bulb. IX. Handout Masters See energy posters. X. References For information about energy and work: (search for energy) 10