3.P 10.1 and 10.2 Forms of Energy

Transcription

1 3.P 10.1 and 10.2 Forms of Energy STEMscopedia Forms of Energy Addressed Benchmarks: SC.3.P.10.1: Identify some basic forms of energy, such as light, heat, thermal, sound, electrical, and mechanical. SC.3.P.10.2: Recognize that energy has the ability to cause motion or create change. You probably already have some idea what energy is. Energy is easy to recognize, yet it can be hard to describe. Where do you think you have seen energy today? How do you think you will use energy tomorrow? Let s nd out more! What is energy? How do we use it? Energy is the ability to do work. Energy is also needed to cause something to change. Neither statement gives a clear idea of what energy really is. The best way to understand energy is to look at each of the forms of energy all around you. Types of Energy Mechanical Energy Thermal Energy Light Energy Sound Energy Electrical Energy Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Thermal energy, another name for heat energy, is the amount of heat energy that can be measured in an object. Light energy is a type of energy that travels in waves and allows us to see. Sound energy is the energy that is produced by sound vibrations, allowing us to hear. Electrical energy, or electricity, is the movement of an electrical charge from one place to another. Mechanical Energy One type of mechanical energy is the energy of motion. Another type of mechanical energy is stored energy. When you lift a book over your head, you give it stored mechanical energy. If you drop the book, the stored energy is changed to energy of motion as the book falls. 1/10

2 The roller coaster pictured above is another example of the two kinds of mechanical energy. The car follows the tracks up and down over the hills. As this happens, mechanical energy changes back and forth between stored energy and energy of motion. The car has stored energy when it is stopped. When it is moving, it has mechanical energy. Both kinds of mechanical energy are all around us. When a ball is thrown into the air, it has energy of motion. It also gains stored energy as it rises. 2/10

3 When someone pulls back on the chains of a playground swing, as shown in the picture above, the swing moves higher. As the swing moves higher, it gains stored energy. As the swing comes back down, the stored energy changes to energy of motion. Stretching a rubber band gives it stored energy. Think about where it has the most of each type, as well. What happens when you release the rubber band? The rubber band gains energy of motion as it ies through the air. 3/10

4 Thermal Energy Everything on Earth is made of particles much too small to see. These particles are always moving. The faster they move, the more thermal energy, or heat energy, they have. Thermal energy is the amount of heat energy that can be measured in an object. As something gains thermal energy, or heat energy, its temperature rises. particles the tiny building blocks of all things We burn fuels to release thermal energy. Some common fuels are gasoline, coal, natural gas, and wood. These materials contain stored thermal energy. We use the heat they release to heat our homes and cook our food. Heat from burning gasoline can be changed into mechanical energy. We use this energy to move our cars. We use heat from burning natural gas to cook food. Light Energy Another form of energy is light energy. Light can be generated by the sun, lightbulbs, or re. Light travels in waves. These waves can travel through glass, water, and even empty space. The light we see can be separated into all the colors of the rainbow by using a prism. When the colors are mixed together, the light appears white. This rainbow is made up of light waves we can see. 4/10

5 10/19/2018 STEMscopedia STEMscopes Due to the size of the light waves, some light energy cannot be seen. However, these invisible waves are still useful. The energy in a microwave oven uses waves that we cannot see but that can cook our food. Doctors and dentists can see inside our bodies by using X-ray machines. X-rays are other waves that we cannot see but that we know are there. These doctors are studying an X-ray. Sound Energy Sound, like light, travels in waves. The length of a sound wave determines the sound s pitch. Pitch is a measure of how high or low a sound is. A whistle is highpitched. A bass drum is low-pitched. Do you think sound can bounce? It sure can! Think of an echo if you yell into a canyon. That echo is just your sound that bounced back to you. Sound energy and light energy also have some important differences. Light travels much faster than sound. That is why we see a lightning ash before we hear the thunder. Also, light can travel through empty space, but sound cannot. Sound needs a material such as air or water to carry it. Suppose you were in a space station traveling through empty space. If a supply rocket from Earth pulled up beside the station, you would never hear it coming. There is no way for sound to travel in space like on Earth. Sound is how most people communicate in everyday life. When we speak or sing, vocal cords located in our throats vibrate, which causes air particles to vibrate. These vibrations are sound waves carried through the air. Sound waves enter other people s ears and cause their eardrums to vibrate. These vibrations send signals to our brains. Our brains recognize the vibrations as words. 5/10

6 You can see sound waves by using special tools. Long waves produce sounds with pitches different from short waves pitches. Electrical Energy Electrical energy, or electricity, is the movement of an electrical charge from one place to another. It can be transferred short distances or very long distances. We use electricity every day to power appliances in our homes. Televisions, radios, and lamps are just a few of these appliances. Lightning is a form of electricity found in nature. Can you think of other things that are powered by electricity? Raindrops fall from a cloud and run downhill into a stream. Water in the stream goes over the top of a waterwheel. This causes the waterwheel to spin. Water falls off the wheel and splashes below. How many different types of energy can you see or could you hear? 6/10

7 The waterwheel spinning is an example of energy. Answer The waterwheel spinning is an example of mechanical energy. The water falling to the bottom would create energy. Answer The water falling to the bottom would create sound energy. You can see the waterwheel because energy is shining on it. Answer You can see the waterwheel because light energy is shining on it. Can you nd any other types of energy in the picture? Answer Answers will vary. Temperature is not the same as thermal energy. Remember, thermal energy is caused by the motion of tiny particles. Temperature measures how fast the particles are moving, or heat. We can measure the temperature of water, food, and our bodies. 7/10

8 A thermometer is used to measure temperature in degrees Celsius or Fahrenheit. Career Corner: Electrical Engineers An electrical engineer is a person who works on things that either transfer or produce electricity. They design and work on lots of different things, such as microchips, radios, motors, computer processors, and global positioning systems (GPS). An electrical engineer uses computers and math every day in their job, so these skills are very important to people in this career. This electrical engineer is working on a re alarm system. The short story below describes six forms of energy. As you read the story, circle each type of energy, using these colors. You may have more than one circle for each type of energy. Stored Mechanical Energy Green Thermal (Heat) Energy Red Mechanical Energy of Motion Purple Light Energy Yellow Electrical Energy Orange Sound Energy Blue 8/10

9 Brush Width: 5 Arial Answer Place your head on your desk. Tap lightly on the desk. Is the sound loud or soft? Pick your head up off your desk. Tap lightly on the desk again. Did you hear a difference in the sound of the taps you made? Why do you think the taps sounded different? Sound travels better through solids, such as your desk, than it does through air. When you put your ear to your desk, the sound goes directly from the desk to your ear. When your ear is not on your desk, the sound travels from the desk, through the air, to your ear. Since sound travels better through the solid (your desk), the taps sound louder with your ear pressed to the desk. Energy is all around us. To help your child understand the different types of energy, set up an experiment that incorporates some of the items in your home and outside. Things to include: Hair dryer Radio Flashlight Rubber band Ball Ask your child to identify the type or types of energy in each item. While driving in the car or while at the park, have your child nd things outside of the home that give off each type of energy. Here are some questions to discuss with your child: 9/10

10 1. What is similar about the ways that light and sound travel? 2. What is different about the ways that light and sound travel? 3. What types of energy would you nd in the kitchen? In the living room? 4. Does light travel through all objects? Why or why not? 5. Where in nature would you see electrical energy? 6. What type of energy would you nd in a car that is not moving? In a car that is moving? 2018 Accelerate Learning, Inc. All rights reserved. 10/10