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MAKING MACHINES out of paper and sticks Tara Chklovski an publication Published by: IRIDESCENT 532 22nd Street Los Angeles, CA 90007 Sponsored by: Office of Naval Research (O.N.R.) Written by: Tara Chklovski Edited by: Ioana Urma Book Design & Cover Illustration by: IOANA/Ioana Urma Cover is drawing of "How Things Work Mural" based on Iridescent's educational topics, painted in Iridescent's 1st L.A. Science Studio space (17'x20', 2010). Photography by: Anna Beatriz Galvao Mariana Rutigliano Linda Wong Experiment models by: Alay Bhayani Jeffrey Cui Shraddha Doshi Gloria Hernandez Juan Hernandez Christopher Hong Darryl Hwang Denisa Lleshi Dorina Lleshi Matthew Miller Nellie Querns Elizabeth Windler Technical advisors: Tim Chklovski Toby Cumberbatch Sylvie Denuit Matthew Loth John McArthur Kevin Miklasz Thomas Stakelon Sinchai Tsao Pedagogical advisors: Erika Allison Vanessa Garza Luz Rivas Font is: Avenir, by Adrian Frutiger, 1988 Copyright © Iridescent, 2011 All rights reserved No part of this book may be reproduced or utilized in any form of by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. Inquiries should be addressed to: Iridescent, 532 22nd Street, Los Angeles, CA 90007. introduction 8 bird boat rube goldberg machine make a… 10 12 30 hot air balloon cool house laser maze eye bowl heart plumbing system speaker 32 further reading 14 16 18 20 24 28 contents 4 introduction Have you ever wondered how a gull’s wings work or how your heart is able to pump blood up against gravity, how a hot air balloon is able to lift hundreds of pounds just with hot air? These are just some of the amazing things that you will learn about – by creating your very own unique working versions. To do so, you will need to keep a few things in mind. •Creating something is very satisfying. There is no joy quite like that of creating something new, beautiful, unique, something that is completely yours! •But creating, building, designing, inventing and engineering takes hard work. You must be willing to put in some effort into doing and especially in learning and experimenting. •You need to be courageous. Your model may fail the first time, the second time, the third time. But it is OK! The Wright brothers studied birds, made observations, tested various designs that failed for years and years before their first successful flight. So it is OK for your model to fail many times. Just be brave, listen to what your model is telling you and make changes each time you test it. It will work! •Play around with the materials! Observe, notice how they interact with one another, with your model, with the world. For instance, have you taken two magnets and tried to push like poles together? How far away do you start to feel the repulsion? What does it feel like when the magnets are moved off-axis to each other? What about moving one around the other in a circle? Try these things! That's how you will learn! Only when you play with, observe and listen, will you begin to understand how the world around you works. This is how the great scientists and inventors worked. And you will be one if you do the same! Welcome and share in the pleasure of finding things out! 4 MAKING MACHINES out of paper and sticks 5 make a… bird GLIDE! Design + build + fly bird-shaped gliders. Observe which designs fly the farthest. In nature, birds with long, narrow wings - Sea Gulls, Albatrosses, Swallows and Swifts - are very good gliders. They float in the air for a long time without flapping. Can you think of some other birds with long, narrow wings that are good gliders? If you look from the side, you may notice that birds’ wings are curved. This curved wing shape is called an airfoil. An airfoil changes the direction of the flow of air: it pushes the flow down. According to Newton's laws of motion, if air is pushed down by the airfoil (the curved wing shape), then the airfoil will be pushed up by the air, causing lift. The wings, and bird, lift up. This is the concept of Action-Reaction: every force exerted has an equal and opposite force exerted back. You can do a test of this by throwing a basketball while standing on a skateboard. Did you move in the opposite direction from the ball (you should have!)? Your movement backwards is caused by the force of the basketball pushing back on you. Look also at the angle of the wing (from the side). Do you notice a difference when the wing is angled more steeply? The more steeply the wing is angled, the more lift will be generated, and the bird will go up higher. collect POSTER BOARD OR STIFF SHEET OF PAPER (1 SHEET) NOSE WEIGHT (PAPER CLIPS OR PLAY-DOH) TAPE SCISSORS RULER experiment 1. Observe different birds in nature or by looking at videos. 2. Draw the different wing shapes of the birds you see glide far. 3. Invent a wing shape design of your own by first sketching it out on a piece of paper. This will help you plan out the design shape carefully, because once you cut it out, it will be hard to join the pieces back together! 8 MAKING MACHINES out of paper and sticks 4. Build the body of your bird. Try and choose a shape that will be strong and can survive many crashes. 5. Cut out the horizontal and vertical part of the tail. 6. Draw and cut out the wings. Cut a variety of wing shapes to try. 7. Tape the parts together, making sure the wings and tail are taped evenly on the body. 8. Put a little play-doh or a few paper clips in the nose, as a weight. 9. Throw the plane gently and see how it flies. If it goes up or dives too steeply, it is not balanced. What do you think you can do to balance it better? Try it with the different wings and wing angles. What angle works best on your bird? Why do you think this reflect angle works best? What wing shape helps your bird go farthest? What are you proud of observing from nature? 9 boat LEARNING FROM BIRDS: design + build + sail a sailboat. Observe which direction the sail needs to be pointed in so that the boat can go forward. Have you ever wondered how sails help a boat to move forward? You may have noticed that the sails of sailboats - pushed by the wind or flow of air - are curved (in cross-section or when looking at them from the side, bottom or top). This curved shape is called an airfoil (just like on a bird’s wing - see bird project p. 10). In the sailboat, the airfoil changes the direction of the flow of air, pushing the air back in a certain direction. You can think of it as a kind of reflector for the air. The air hits the sail or airfoil and bounces back off of it. The direction the air is pushed off of it depends on the angle of the sail to the incoming wind or airflow. When the sail or airflow push the incoming flow of air or wind back, the boat is pushed forward. The boat is pushed forward exactly in the opposite direction to the direction that the wind is pushed back. This is because, as Newton's laws of motion state, for every force that the sail exerts on the air, there must be an equal and opposite force from the air on the sail. This is the concept of Action-Reaction. collect PLASTIC BOTTLE WOOD SKEWER CONSTRUCTION PAPER ALUMINUM FOIL WIRE TAPE SCISSORS RULER LARGE BOX FAN LARGE OPEN CONTAINER OF WATER experiment 1. Draw out your sailboat design on a piece of paper before start- ing. This will help you plan out the design carefully, because once you cut the bottle, it will be hard to join the pieces back together! 2. Based on your sketches, build the body of the boat out of the 10 MAKING MACHINES out of paper and sticks plastic bottle pieces (ask an adult for help cutting the bottle, making sure edges aren't sharp or pointy). 3. Attach the skewer to the boat base. 4. Shape the aluminum foil into a curved sail form around the skew- er. Design the sail so that it doesn’t get crushed (as aluminum foil can get crushed very easily). Try and put in some support braces using posterboard or wire. 5. Test the sailboat in the water and see which direction the boat goes depending on how you direct the fan and how you angle the sail. What sail angle helps the boat sail the farthest? Why do you reflect think this angle works best? What sail shape helps your boat go farthest? What aspect of your boat are you most proud of designing? 11 rube goldberg machine ENERGY TRANSFER! Design + build + set in motion a Rube Goldberg machine. Rube Goldberg machines are contraptions that perform simple tasks in unique, fun, and indirect ways. Some Rube Goldberg machines use a complicated series of actions to simply move an object from one place to another. Any object that is moving, has what is called kinetic energy; giving an object more speed means giving it more kinetic energy. Kinetic energy can be transferred from one object to another by a collision, like when one domino tips over into another domino. Even without a collision objects can gain kinetic energy if they fall down or roll down a ramp. The goal of a Rube Goldberg machine is to find creative ways of making this type of energy transfer happen using a variety of simple machines (see experiment) attached together in the form of a complex machine. collect experiment ANYTHING THAT YOU CAN FIND AROUND THE HOUSE! Try and make YOUR OWN UNIQUE Rube Goldberg that has each of the six simple machines listed below and can transfer energy in at least five different ways: PULLEY: A simple machine that uses grooved wheels and a rope to raise, lower or move a load. LEVER: A stiff bar that rests on a support (called a fulcrum) which lifts or moves loads. WEDGE: An object with at least one slanting side ending in a sharp edge, which moves material apart. WHEEL & AXLE: A wheel an axle lifts or moves loads. INCLINED PLANE: A slanting surface connecting a lower level to a higher level. SCREW: An inclined plane wrapped around a pole which holds things together or lifts materials. 1. Decide on the task that you want the Rube Goldberg machine to do. For example, to move a ball into a box or to open a door. 12 MAKING MACHINES out of paper and sticks 2. Think of ways you can make your materials interact with each other. How can one energy transfer start a chain of actions? Test each energy transfer before putting the entire contraption together. Make sure you think about five different energy transfers that you will implement. 3. Once all the testing is done, put your Rube Goldberg together and watch it perform the task you chose to do in a very complicated, but fun way. If the Rube Goldberg stops midway, retest and redesign that failed energy transfer. How many different energy transfers did your Rube Goldberg reflect have? What are some energy transfers that you observe in your room, outside your window, in the playground? How can you modify your Rube Goldberg machine to use wind to transfer energy? How about water? How about solar energy? 13 hot air balloon HOT AIR! Design + build + fly a hot-air balloon to lift a weight. The better designed the balloon is, the more weight it will be able to lift. Why do hot air balloons rise up? Hot air balloons rise because they are filled with air hotter than the air around them, and hot air is lighter than cold air. Why is hot air lighter than cold air? When a material is heated, its molecules absorb the heat or energy and with this extra energy are able to move around at greater speeds. In objects that can stretch and expand, molecules with extra energy can move farther apart. When the molecules move, the object grows in size or volume. It doesn't change in weight, though, because the number of molecules doesn't change. It is made of the same number of molecules, just located farther apart. This makes the object less dense, but maintains its weight. When we start heating the air of a hot air balloon, the air molecules start moving around with more energy. As the hotter air expands, the balloon expands, but its weight does not change right away. Once the balloon has expanded as far as it can, then the energetic molecules start escaping out of the hole at the bottom. This leaves less molecules inside, making the balloon lighter than the cooler air around it. The balloon rises. collect POSTER BOARD (1 SHEET) TISSUE PAPER (10-12 SHEETS) GLUE STICK SCISSORS RULER PIECE OF WIRE TO SHAPE INTO A RING STRING HAIR DRYER experiment 1. Draw and cut a template for the hot air balloon side panels out of the poster board. You will use this to make tissue paper cutouts of the same size. Draw the typical shape you see in modern balloons or try creating new shapes you would like to test. 2. Using your template, cut 8 tissue paper side panels. 14 MAKING MACHINES out of paper and sticks 3. Glue the panels together into a balloon shape. 4. Cut out a circular piece of tissue paper to cover the top of the hot air balloon and glue it on. 5. Cut some wire coil and shape into a circle. 6. Place the coil at the bottom of the balloon, fold over the tissue paper over it, covering it, and glue it in place. 7. Make a basket out of the poster board and attach it with string or tape to this coil ring, and place a weight in the basket. 8. Heat up the balloon with the hair dryer, let it go and watch it rise! How do you think the size of the balloon affects how much reflect weight is in the basket? Why do you think size makes a difference? Does shape make a difference? Look at early balloon designs. Try them out and see if a particular shape is better at carrying more weight. What are you proud of learning? 15 cool house CONVECTION! Design + build a house with doors and windows carefully positioned to help remove the hot air and cool the house passively (without using a fans or the AC). The goal is to save energy. If you have an attic space or have ever been in an attic space on warm days, have you noticed how much warmer it is in there than in the rest of the house? How about in the basement? In the days before refrigerators, basements - because they are much cooler were used to store food items. Next time it's hot inside, try lying down on the floor and see how you feel. It's cooler than when standing up, isn't it? Warm air rises to the top because it is lighter, or less dense, than cold air. Air molecules with more heat, or energy, move around at greater speeds and end up farther apart. So in the same amount of space (volume), warmer air will have less molecules in it than colder air. This makes it less dense or lighter, and it makes it rise up. As warm air rises and cold air sinks, a directional movement of air is created which is called a convection current. Have you ever wondered why on a warm day it is warmer inside a parked car than outside? This concentration of heat inside the car is caused by the greenhouse effect. A greenhouse is an enclosure made of glass or other transparent materials - typically for plants that allows sunlight in, but then traps some of the sunlight's energy inside. This trapped energy is heat. A car parked in the sun heats up for the same reason, heat energy from the sunlight gets trapped. collect CONSTRUCTION PAPER TAPE SCISSORS TWO INCENSE STICKS & HOLDER CAUTION: only conduct this experiment under adult supervision. experiment ONE MATCHBOX THERMOMETER 1. Knowing that warm air rises and cold air sinks, can you think about which parts of your house are the hottest? Sketch and design the location of your openings (doors and windows) so that 16 MAKING MACHINES out of paper and sticks the heated air will come out and the cool outside air will come in. 2. Build your cool house out of construction paper. 3. Once the house is complete, put a lit smoking incense stick inside the house in an incense stick holder. BE CAREFUL NOT TO TOUCH THE PAPER WITH THE INCENSE STICK AND SET IT ON FIRE! If the placement of windows and doors is well designed for cooling with natural ventilation, then the smoke will come out. 4. Place a thermometer at various points inside the house. Where do you get the highest reading? What design worked best? What placement of openings reflect helped more smoke to get out of the house? Where did you get the highest temperature reading? Why do you think this is? Can you think of some other examples of convection you can see around the house? 17 laser maze Design a laser maze that reflects the laser beam through as many obstacles as possible. When light waves hit a material, they cause the atoms (specifically, the electrons in metals) to oscillate (move back and forth). These oscillations cause the atoms to radiate a small wave back out in all directions. The reflected waves of many atoms combine to form a visible reflection. In the case of metals, the electrons in the atom's outer shell (farthest from the central nucleus) are not attached to the atom; they are free to move throughout the metal with very little resistance. When light shines on metal, it makes these free electrons oscillate or vibrate and the energy reflected is visible light. A mirror is mostly made of glass, but it also has a thin metallic film on the back side. It is that metallic film that reflects the light passing through the glass. The glass is only there to hold up the very thin film. A few ideas, tips and terms to be aware of: ∙∙ Light paths are only visible when there are particles in the intervening medium (such as smoke or fog or dust particles in the air). ∙∙ Moving a mirror back doesn’t increase the amount viewed in it. ∙∙ Incidence angle = angle at which light hits a surface. ∙∙ Reflection angle = angle at which light is reflected off a surface. collect FOG MACHINE & FOG JUICE (FROM A PARTY SUPPLY STORE) LASER POINTER (KEY CHAIN OR BIGGER IF POSSIBLE) MIRRORS CONSTRUCTION PAPER TAPE POPSICLE STICKS SCISSORS experiment CAUTION: only conduct this experiment under adult supervision. 18 1. Cut a pattern of holes in the construction paper. Your obstacle course will be more challenging if the holes are very small. 2. Glue popsicle sticks along the side of the paper so that the obstacle course can stand upright. Stand them up in play-doh. MAKING MACHINES out of paper and sticks 3. Use play-doh to make the mirrors stand upright. 4. Turn on the fog machine and point it towards the obstacle course. 5. Turn on your laser pointer and reflect the beam off of as many mirrors as possible so that the beam can go through the obstacle course holes, from one end of the maze to the other. Do you see a red path of light when you shine the laser point- reflect er onto a mirror or something else? Is it what you expected? What happens when you add fog? Do you see the light path? What do you think is happening? Where is the image you see in the mirror? Can you illustrate your thoughts on how it is formed? What happens when you move the mirror back? Do you see more of yourself or of an object? Can you draw and explain how the light travels in your obstacle course? 19 eye bowl REFRACTION! Build an eye model and see how its lens bends light to reproduce an image. Light waves travel at different speeds through different mediums (materials). As light crosses from one medium into another, the same wave will change the speed at which it is traveling. This happens, as you probably guessed, because the two mediums interact with the light in different ways. The way that light travels through a materials is by passing on energy. As a light wave enters a material, it hits and gets absorbed by the electron of an atom in that material. The electron doesn't keep the energy for long though, and soon it re-emits the light wave. This process continues from atom to atom, where each atom is like a baseball player catching the light wave and then throwing it to the next atom. The atoms of different materials take different amounts of time to catch and throw the light waves, making light travel more slowly when it enters a material. In a vacuum (an empty medium without atoms) light travels at a speed of 299,792,458 meters per second or about 186,282 miles per second. Through a material, it takes longer. Imagine sitting on a boat and looking out at a fish in a lake. For your eye to see the fish, there must be light traveling from the fish to your eye. This light wave travels slowly through the water and then when it enters the air it speeds back up. The path of the light wave makes an angle with the boundary between the water and the air. At this boundary the path of the light bends. To understand why light bends, lets use an analogy. Imagine you are pushing a stray shopping cart (lightwave) from the grass (water) onto a parking lot (air). If you go straight from the grass into the parking lot the cart will speed up after crossing the boundary. What if you approach the boundary at an angle, so that the front right tire hits the pavement first? What happens? The front right wheel will begin moving faster than the other wheels and this will cause the cart to start to turn to the left. Once you leave the grass you will be pointed in a new direction. Going over the 20 MAKING MACHINES out of paper and sticks boundary bent your path, just like the light wave's path became bent, all because the wave moves at different speeds in different materials. This is called refraction. Understanding refraction can help you better understand how the eye works. The lens in your eye (the front curved part of the eyeball) bends the light waves which enters it. The light waves are bent so they come together or “focus” at a particular distance back from the lens, called the focal distance. The lens in your eye works the same as other lenses (camera, telescope, microscope): it bends the light waves, changing their direction of travel. Lenses can do this because they are made of a different material than the mediums or materials around them. Light passing through the air is bent by a glass lens. If an object is placed in front of a lens, some of the light that bounces 21 off the object will pass into the lens. This bounced light is refracted through the lens, and becomes focused into an “image.” Think about a camera. If you put an object in front of the camera, light bounces off the object and passes through the lens where it is refracted. The lens uses refraction to focus the light to form an image. On a digital camera, that image is what is displayed on the back screen. Pick up one of the magnifying lenses, hold it away from you and look at your friends through it. How can you tell that the light passing through the lens is changing direction? collect TWO CLEAR PLASTIC BOWLS (THAT YOU CAN SEE THROUGH CLEARLY, WITHOUT DISTORTION) A SHEET OF WAXED PAPER OR TRACING PAPER CLEAR PACKAGING TAPE (OR MASKING TAPE) SCISSORS A LENS OR MAGNIFYING GLASS experiment 1. Put the bowls together, rim to rim (opening to opening). 2. Tape them together. It should look sort of like a flattened ball when you are done. This model represents the eye-ball. 3. Cut a circle out of the waxed paper or tracing paper. The cut-out paper should cover the bottom of one of the bowls. 4. Now tape it to the bottom of one of the bowls. The paper will act as a screen for the image to form. 5. Tape the lens to the bottom of the bowl on the side opposite the paper. 6. Place your eye model between the object you want to look at and your own eye. Adjust the distance between the model and your eye until a clear image is formed on the screen. Look at the paper. Do you see an image on the paper? What is the shape of the image? 7. Is it upside down? What is its color? 8. Point the eye model in a slightly different direction and observe what happens to the image. What do you see if you point the lens of your eye model at your friends or parents? 22 MAKING MACHINES out of paper and sticks 9. Describe the image you see. What was the hardest part of building the model? Can you reflect use the eye model to show your friends or parents how an eye works? What was the best part of this experiment? 23 heart CIRCULATION IN YOUR HEART! Design + build + operate an artificial heart. Your heart pumps and circulates blood to every part of your body so that all of your cells get the oxygen and nutrients they need to survive. In a single day, your heart can pump about 1,000-2,500 gallons of blood. To keep you alive, your heart works without any breaks or rests! But, unfortunately, the heart is not indestructible. People can suffer from the break down or weakening of the heart, or they can be born with a weaker heart. This can result in heart failure, where the heart can no longer pump enough blood for the body's needs. In the most severe cases of heart failure, the only long term solution is to replace the heart. For many years the only way to replace a heart was through a transplant, where a failing heart is replaced with a living heart from an organ donor. Since this process was, for many reasons, very difficult, more recently, doctors, scientists, and engineers have come up with another transplant option: an artificial heart! Making an artificial heart was very hard because it was trying to take the place of something very complex. There are four chambers in your heart, and each one has a specific job to do to make sure your body has enough oxygen. Blood comes into the right atrium from the body. This blood is low in oxygen and high in carbon dioxide. Blood is then pumped into the right ventricle and the next stop is the lungs to drop off the carbon dioxide and pick up more oxygen. From the lungs the blood is pumped back to the left atrium and then on to the left ventricle which finally pumps the blood back into your body. An artificial heart has to be designed to do the job of each original chamber correctly. That's tough to do! On top of that, an artificial heart needs a new power source. A real human heart is made of muscle, and just like the muscles in your arms and legs, the heart depends on the food you eat to give it the energy it needs to pump blood, but an artificially heart can't use the food you eat. There are several artificial hearts that exist, but they too have some issues such as size, weight, and attachments. 24 MAKING MACHINES out of paper and sticks JARVIK 7 was the first artificial heart used in people 1982. This heart has only two pumps which replace the two lower chambers of a person's heart that has stopped working. The power system for this heart is large and bulky and it connects to the pumps through tubes that poke through the skin – ouch! ABIOCOR, a more recent version, has a mechanical pump which completely replaces the pumping action of the lower chambers of a person's heart. It allows doctors to completely remove a person’s heart and replace it with a whole new system. The difficulty with this model is that a lot of equipment has to be placed inside the body. The equipment is bulky and puts a lot of pressure on the other organs. 25 collect PLASTIC TUBING FOUR SMALL PLASTIC BOTTLES FOOD COLORING THICK STRAWS THIN STRAWS SCISSORS TAPE BALLOONS experiment 1. Draw a diagram of the four chambers of the heart and how they connect to each other to use as an organizational guide. You will use the plastic bottles to represent these chambers. 2. Take the four bottles and make holes in each of the caps, big enough to fit the tubing. 3. Tape two bottles together with the cap sides touching. Do the same with the two remaining bottles. 4. Take a sharp pencil or scissors and make a hole at the bottom of the first two bottles that represent the upper chambers of the heart and two holes on the top of the bottles that will represent the lower chambers of the heart. 5. Use the clear tubing to connect the top bottles to the bottom bottles through the holes made. The bottom bottle should have the rubber tubing touching the bottom of the lower bottle so that when the bottom bottle is squeezed water will flow up the tube and pour water into the top bottle. 6. Remember to put valves in the caps of the bottom bottle so that no water is leaking back up to the top bottle when the bottom is squeezed. Do this for the other side two in order to complete your four chambered heart. reflect What can you change about your four chambered heart to make it pump better? What would happen if you only had a three chambered heart? Where would the blood from the top chamber go? Why does the heart need a left and right side? 26 MAKING MACHINES out of paper and sticks paste your heart diagram here 27 plumbing system Design a plumbing system which can distribute water to five “cells” in your body in under 30 seconds! Your circulatory system controls the movement of blood through your heart and throughout your whole body. The blood circulates (moves) in a continuous, closed loop. The movement is generated (started) by the pumping action of the heart. Your house also has a circulatory system, but instead of blood, it pushes water around. It is called the plumbing system and it is composed of pumps, pipes, and valves. Both your body and your house have circulatory systems that operate using the same parts and concepts: ∙∙ A pump: the heart (body); a mechanical pump (house). ∙∙ Distribution vessels: arteries and veins (body); pipes (house). ∙∙ Control valves: valves in the heart (body); faucets and the toilet lever (house). ∙∙ They transport both nutrition and waste: blood transports oxygen and nutrients and removes cell waste (body); the plumbing system carries both fresh and waste water (house). One of the most important tasks of the circulatory system is to deliver nutrition and remove waste through blood - to and from the cells - at incredibly high speed. The size of your blood vessels controls the speed of blood flow: in large vessels the flow is slow, while in small vessels it speeds up. This is because the same amount of blood needs to move through under the same pressure (put out by the pump of your heart). If the opening is smaller, the pressure will be greater and it will be pushed through faster. collect PLASTIC TUBING THICK STRAWS THIN STRAWS SCISSORS TAPE FIVE CUPS BALLOONS 28 MAKING MACHINES out of paper and sticks 1. Sketch ideas for your design, figuring out how the system will experiment work to fill up all the cells at the same time. This is necessary. 2. Use the materials listed to construct your plumbing system. 3. Check to see whether or not you have any leaks in your pipes. Also check to see if you need to add any valves to control the flow of “blood.” 4. Pour water into the entry part of your plumbing system and watch how it flows! What could you change about your plumbing system in order reflect for the ”blood” to flow to the cells more quickly? How about more slowly? How does the size of your pipes affect the speed of blood flow? 29 speaker USING PRESSURE WAVES TO CREATE MUSIC! Design + build a speaker that will use electricity and magnets to put pressure on the air and create sound waves (musical sounds). Have you wondered how you are able to hear a sound that was emitted really far away? Most times you can't feel or see anything. Sometimes though, if the sound is loud, you can even feel vibrations! Sound can be thought of as waves of pressure that move longitudinally (in the directional line of the sound without going up and down). Sound can move through all kinds of mediums: air, water or even hard materials like wood. The medium or material the sound moves through is made up of tiny molecules. When these molecules are made to vibrate by some force, they transfer or pass the vibrations on to the molecules next to them. This continuous transfer results in a sound wave, a wave of transferred vibrations. You can create a sound with your vocal chords, but also by moving something with your hands, such as waving a fan through the air. Try it. Do you hear something? Those are molecules of air passing the energy you threw at them on as vibrations in the form of a sound wave. You put pressure on the air and made it vibrate! collect NEODYMIUM MAGNET WIRE 32 OR 34 AWG (AMERICAN WIRE GAUGE) PLASTIC CUP ALLIGATOR CLIPS SANDPAPER TAPE GLUE SCISSORS PENCIL HEADPHONES experiment 1. Leaving a 10 centimeter tail of the wire free at the beginning and at the end, wrap the wire around a rolled up piece of construction paper about 50 times. 30 MAKING MACHINES out of paper and sticks 2. Use sandpaper to rub the insulation off the ends of the tails. 3. Tape the magnet against the outside, bottom, of a plastic cup. 4. Cut the speakers off of the headphones and strip away the plas- tic insulation to expose all four wires. Sand away any insulating coatings on these wires. 5. Plug in the headphone jack and turn on the sound for the device you are using. 6. Connect some of the exposed wires from the headphones to the free tails of the coiled wire. Test your choice by holding the rolled-up paper up and down with the coiled wire by the magnet. Experiment with the connection until you hear the right sounds. How can you change your design to increase the volume reflect of your speaker? What can you do if the sound quality isn’t good? How does the size of the cup affect the sound? 31 further reading EASY The Great International Paper Airplane Book by George Dippel, Howard Gossage and Jerry Mander, 1971. Body. Make It Work! by Andrew Haslam, 2000. Flight. Make It Work! by Andrew Haslam, 2000. Insects. Make It Work! by Andrew Haslam, 2000. Photography. Make It Work! by Andrew Haslam, 2000. Sound. Make It Work! by Andrew Haslam, 2000. Everyday Machines: Amazing Devices We Take for Granted by John Kelly, with David Burnie and Obin, 1995. The Robot Zoo: A Mechanical Guide to the Way Animals Work by John Kelly, Dr. Philip Whitfield and Obin, 1994. The New Way Things Work by David Macaulay, with Neil Ardley, 1998. The Amazing Book of Paper Boats: 18 Boats to Fold and Float by Melcher Media (creator), with Willy Bullock (illustrator) and Jerry Roberts (text author), 2001. Illustrated Guide to Aerodynamics by Hubert Smith, 1991. 700 Science Experiments for Everyone compiled by UNESCO, 1964. 32 MAKING MACHINES out of paper and sticks Amateur Naturalist: A Practical Guide to the Natural World by ADVANCED Gerald Durrell with Lee Durrell, 1993. Why Things Break: Understanding the World By the Way It Comes Apart by Mark Eberhart, 2004. The Seven Secrets of How to Think Like a Rocket Scientist by James Longuski, 2006. How to Design a Boat by John Teale, 2003. The Simple Science of Flight by Henk Tennekes, 1996. Physics, Fun, and Beyond: Electrifying Projects and Inventions from Recycled and Low-Cost Materials by Eduardo de Campos Valadares, 2005. The Flying Circus of Physics by Jearl Walker, 2006. 33