Capturing Human Energy PDF

Capturing Human Energy...

Capturing Human Energy Chapter 1: Hand-Crank Flashlight Harnessing Human Energy    © 2018 The Regents of the University of California. All rights reserved. Permission granted to purchaser to photocopy for classroom use. Image Credits: Shutterstock Have you ever used a hand-crank flashlight? You turn a crank on the outside of the flashlight and the crank turns a generator inside the flashlight. Hand-­crank flashlights are powered by energy from A generator is a machine that stores energy by the human body, so they never need new batteries. charging a battery. When the generator turns, it converts kinetic energy to electrical energy and then stores it in a battery as potential energy. The potential energy stored in the battery can be used right away or saved for later. The energy that powers the light comes from the battery—but before that, it came from you. When you use a hand-crank flashlight, you are using your body’s energy to power a light! MSSCI_PS_HHE_AR_12 How a Hand-Crank Flashlight Works Turning the crank......turns the generator......which charges...and powers the light. the battery... = energy transfer When you turn the crank on a hand-­crank flashlight, kinetic energy from your body turns the generator inside the flashlight. That kinetic energy is converted into potential energy and stored in the battery, which can then make the light bulb work. Capturing Human Energy 1 The disadvantage of a hand-crank flashlight is that you have to turn the crank in order to charge the battery. The longer you plan to use the flashlight, the more energy you need to store and the more cranking you have to do. However, turning a crank isn’t the only way to store energy in a generator. There are lots of Harnessing Human Energy    © 2018 The Regents of the University of California. All rights reserved. Permission granted to purchaser to photocopy for classroom use. Image Credits: Shutterstock other ways to release kinetic energy: bouncing, stretching, compressing, and other forms of motion all involve kinetic energy, which means they can be used to turn a generator and store Squeeze-lever flashlights are similar to hand-crank electrical energy in a battery. Now imagine flashlights: both convert kinetic energy from the if those motions allowed you to charge that motion of the human hand. To make a squeeze- battery just by doing everyday activities— lever flashlight work, you squeeze the handle. things you have to do anyway, like walking. Some people have invented devices that do just that: convert kinetic energy from everyday activities into electrical energy, storing the energy in batteries as potential energy that can be used to power flashlights, cell phones, and other devices. Students, business people, engineers, and even hobbyists have come up with ideas for inventions like this. You can read one or more of the chapters that follow to find out about a few of them. 2 Capturing Human Energy  Chapter 2: Energy-Capturing Backpack When you wear a backpack, the backpack moves up and down a bit as you walk. Like all motion, this up-and-down movement is a form of kinetic energy. An energy-capturing backpack uses that kinetic energy to charge a battery. One way that an energy-capturing backpack can work is by hanging the heavy part of the backpack from springs, allowing it to bounce Walking produces an up-and-down motion that hikers up and down as you walk. The bouncing can use to power small devices like cell phones. turns the wheel of a generator. When the Harnessing Human Energy © 2018 The Regents of the University of California. All rights reserved. Permission granted to purchaser to photocopy for classroom use. generator turns, it converts kinetic energy to electrical energy and then stores it in a battery as potential energy. The potential energy stored in the battery can be used to power a cell phone or other electrical device. MSSCI_PS_HHE_AR_17 How an Energy-Capturing Backpack Works Image Credits: (l-r) Dorling Kindersley/Getty Images; Shutterstock; Science Journal; Shutterstock generator Walking......makes the generator...which charges...and powers a in the backpack move... the battery... cell phone or other equipment. = energy transfer When you use an energy-capturing backpack, the motion of walking powers a generator that charges a battery. You can use the energy in that battery to charge small devices. Capturing Human Energy 3 Chapter 3: Energy-Capturing Bike A spinning bicycle wheel has lots of kinetic energy. The kinetic energy provided by the rider’s pedaling makes bicycles a good way to capture energy from the human body. When you use the brakes on an energy-capturing bicycle to slow down, the kinetic energy of the spinning wheel is converted to electrical energy and stored in a battery as potential energy. That potential energy could be used to power all kinds of electrical devices. Some The Copenhagen Wheel fits into a bicycle wheel energy-capturing bicycles use the potential and stores some of the rider’s energy for later use. energy stored in the battery to run a motor Harnessing Human Energy © 2018 The Regents of the University of California. All rights reserved. Permission granted to purchaser to photocopy for classroom use. that helps turn the wheel and gives the rider It was your kinetic energy that was transferred an extra boost. This can be a big help when to the bicycle wheel, then transferred to riding up steep hills! Using a motor might sound the generator and converted into electrical like getting a free ride from the energy stored energy, then stored as potential energy in the in your bicycle. However, if you trace it back, battery, then used to power the motor that that energy first came from you, the rider. gave you a boost when you needed it most. MSSCI_PS_HHE_AR_21 How an Energy-Capturing Bicycle Works Image Credits: (tl-tr) Michael D. Spencer; Shutterstock; (b) Michael D. Spencer; Shutterstock generator The spinning wheel......makes the generator...which charges...which can power a in the wheel move... the battery... motor that helps turn the wheel when the rider wants an extra boost. = energy transfer On a bike with the Copenhagen Wheel, kinetic energy from the rider turns a generator that charges a battery, which can help power the bike when the rider needs some extra help. 4 Capturing Human Energy  Chapter 4: Energy‑Capturing Knee Brace An energy-capturing knee brace uses the kinetic energy of your moving leg to charge a battery. The knee brace has a generator inside it. You bend your knee with each step, and as you straighten it again, the movement makes the generator spin. The kinetic energy in the spinning generator is converted to electrical energy, then stored in a battery as potential energy. You can use that potential energy to power a cell phone or other device. Harnessing Human Energy    © 2018 The Regents of the University of California. All rights reserved. Permission granted to purchaser to photocopy for classroom use. The knee brace spins the generator when you’re straightening your knee instead of when you’re bending it. That’s because your muscles don’t have to work as hard to straighten your knee as they do to bend it. This makes the An energy-capturing knee brace harvests energy knee brace easier to use—you don’t have with the bending and straightening of the leg. to work very hard to spin the generator. MSSCI_PS_HHE_AR_22 How an Energy-Capturing Knee Brace Works Image Credits: (tl-tr) SFU Locomotion Lab; Shutterstock (b) SFU Locomotion Lab generator Taking a step......makes the generator in...which charges...which can power a the knee brace move... the battery... cell phone or other equipment. = energy transfer When you use an energy-capturing knee brace, the motion of your steps turns a generator in the knee brace. That energy is converted to potential energy and transferred to a battery. The energy in the battery can be used to power a small device, like a cell phone. Capturing Human Energy 5 Chapter 5: Energy-Capturing Rocking Chair Most chairs can’t convert energy from the body into electrical energy. However, an energy-capturing rocking chair can! Energy­ capturing rocking chairs use the motion of rocking to power electronic devices—a lamp attached to the chair or a charger for phones and other electronic devices. The process begins with the kinetic energy your body uses to rock the chair, usually by pushing your foot An energy-capturing rocking chair uses the motion against the floor. That kinetic energy makes the of rocking to power electronic devices. chair rock back and forth and spins a generator Harnessing Human Energy    © 2018 The Regents of the University of California. All rights reserved. Permission granted to purchaser to photocopy for classroom use. built into the rockers (the parts of the chair that rest on the floor). The kinetic energy in the spinning generator is converted into potential energy and stored in a battery built into the body of the chair. The energy can be used right away to power the lamp or the device charger, or it can be stored for later. When using stored energy to power the lamp or the device charger, you don’t need to rock to keep them working. Image Credits: (tl-tr) Micasa Lab; Shutterstock; (b) Micasa Lab When you rock an energy-capturing rocking chair, kinetic energy is transferred to a generator on the back of the chair. The generator transfers energy to a battery. Energy from the battery can be used to power electrical devices. 6 Capturing Human Energy