ENERGY Subjects: Grades: Duration:

Science, math, social studies, writing 6-10 Lesson 1: Forms of energy 3-5 hours. Lesson 2: Converting forms of energy 2 hours.

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Teacher Objectives The purpose of this unit is for students to gain a basic understanding of: 1) The different forms of energy, 2) The conversion of one form of energy to another, and 3) The efficiency of those conversions (a glimpse)

Vocabulary Conductor Insulator

A material that allows heat or electricity to pass through easily A material that does not allow heat or electricity to pass through easily Heat Energy transferred from one object to another related to the activity of the atoms and molecules. Light Electromagnetic radiation that is visible to the eye Kinetic energy The energy of an object in motion Potential energy When an object is in a position to give kinetic energy Chemical energy The energy stored in chemical bonds between atoms. Electromagnetic One of the four fundamental forces in the universe. Gravity is another of the four forces. Efficiency When most of the energy in a system goes to the desired purpose. KEY CONCEPTS 1) Chemical energy is the easiest and most common form for storage of energy. 2) Electrical energy is the most versatile form of energy, as it is easily converted to all other forms of energy, and can do so with precision and relative efficiency.

HOW TO BEST USE THIS UNIT: Students: 1) read ʻStudent Content Reading,ʼ 2) participate in class discussion 3) complete activities and 4) complete assessment.

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Student Content Reading Energy is perhaps the most important commodity in the world, as the days of cheap, easy energy are over. Whether we realize it or not, almost every decision we make in life is directly or indirectly related to energy. You will do well to understand it, know how to use it wisely, and avoid costly mistakes. It isnʼt just a matter of economy. It can be a matter of survival. Hypothermia is a dangerous lack of heat energy that results in discomfort, loss of body parts, or even death. Whether you are driving a four wheeler or a boat, shooting a rifle, or cooking over a campfire, you are transferring one kind of energy into another. Fuel for cooking stoves, generators and machinery convert the chemical energy of fuel into all other forms of energy. Energy is expensive. If we look at our family budget, almost every expense is connected to fuel and its cost. In the Alaskan Bush, freight costs, which are mostly the cost of fuel to deliver an item, almost double the value of that item landed in our town or village. Forms of energy. There are six forms of energy: 1) heat 2) light 3) chemical 4) kinetic (motion) 5) electrical 6) nuclear. Nuclear energy refers to the splitting (fission) or fusing (fusion) of the nuclei of atoms. Since nuclear energy is expensive, complex and dangerous, it is reserved for power plants and submarines. Safer methods of fusion copy the natural dynamic of the sun by fusing atoms of helium. As nuclear energy isnʼt available to us common folks, letʼs focus on the five available forms of energy: heat, light, chemical, kinetic and electricity. We will investigate the 5 forms of energy in terms of: 1) what they are, 2) how one can be converted to another and 3) how we put them to use.

Five Forms of Energy 1) Heat. We heat our homes to keep them livable. High-end commercial clothing and traditional Native fur clothing are both designed to save body heat. Snowmachines provide handwarmers. Chainsaws utilize cooling fins to get rid of cylinder heat. Refrigerators remove heat to prevent food from spoiling. It seems like most of our life has to do with being too hot or too cold, and trying to do something about it. 2

1) What Is Heat? Heat is simply the activity of atoms and molecules. Atoms and molecules are constantly vibrating, or bouncing off each other. Temperature is the measurement of that motion. How lively are the atoms and molecules? If they are vibrating quickly, the object is said to be hot. If they are vibrating more slowly, the object is said to be cold. If the substance is a solid, the molecules vibrate in place. If the substance is a flowing liquid, they vibrate while tumbling over, under, and around each other. If the substance is a gas, they vibrate freely, each seeming to want to escape the others. Discussion: • What do you think heat is? How do you picture it in your mind? …a substance, a liquid, energy? • Make a quick illustration of heat; share the illustrations with the class. • When you think of “heat,” what three words come to your mind? (i.e.sun, fire, stove, sweat etc.) • When you think of “cold” what three words come to your mind? (ice, winter, wet, shiver etc.) List the class responses. Add over time. Activity: If students can handle the activity: Have 5 students step into an area bounded by a loop of rope on the floor. The students are molecules. They gently bounce off each other randomly. When they are “hot” they bounce quickly. When they are “cold” they bounce slowly. Sometimes this works as an illustration. Often it gets out of hand. The students can act as a solid (vibrate in place), liquid (roll, vibrate, and move as part of a flowing liquid) or a gas (Just drift off. Kinda like daydreaming.) What do you think heat is? Illustrate what you think heat looks like. Conductors allow heat to pass through. Insulators slow the passage of heat. Heat energy always flows from a place of high heat to a place of lower heat. When heat flows through an object we say it “conducts” heat. Some materials, like aluminum, conduct heat fairly well. That is one of the main reasons why cylinder heads are made of aluminum, to carry heat away. Other materials, like a foam cup, do not conduct heat well at all. We do not want our hats, boots or gloves to conduct heat from our bodies. Activity: Identify good heat conductors. (Copper, steel, cooking pots) Identify good heat insulators. (Air, glass, polyester fibers, down, cotton, foam) Put hot tap water in containers of different materials. Hold the container. How long does it take to feel the heat? Measure the temperature in each container at 5 minute intervals. Which substance is the best conductor? Insulator? 3

We live in a land where the summers are warm and winters are very cold. Heat control is most important for Alaskan homes. Without an external heat source, none of us could survive. Living in a tent requires a good stove and a considerable amount of wood. Knowing how to manage heat determines how efficient and comfortable our homes and lives will be.

Heat travels three ways: Convection is when air or water move in currents caused by uneven heating. Warm air rises. Warm water rises as well. • If your coat is unzipped at the top and loose at the bottom, convection air currents will carry away the air your body has warmed. • If your home is well insulated, but you leave the downstairs door and an upstairs window open, convection currents will cause cold air to come in the door, the warm air will rise, and leave by the upstairs window. This is convection Activity: Make a simple pinwheel, and put it onto the eraser of a pencil. Hold it over a candle flame. If the pinwheel doesnʼt catch fire first, it will turn with the rising hot air from the candle. Discussion: Why does air go into the firebox of a wood stove and rise out of the stovepipe with no fan or force driving it? (Warm air is less dense than cold air, and rises up the stovepipe. This is convection!) In a Toyo or Monitor Stove, there is no convection, as cold air comes in, and the exhaust exits through the same opening in a side wall. With no convection currents, an electric fan is necessary to force the air in and out. Without the fan, combustion could not occur. Furnaces also require fan driven forced air into the firebox. Discussion: If you are camping out in a cabin, tent or snow shelter, would you rather sleep on the floor or on an elevated surface? (The higher the better. Warm air rises.) On earth, most winds and ocean currents are giant convection currents.

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Activity: Watch the Weather Channel for a period of time. What is the direction of the prevailing winds during both a high pressure and a low pressure area? What is the general direction of the jet stream? Research the ocean currents, particularly where the warm Japanese currents meet the cold Bering Sea currents. In any closed space that is unevenly heated, like the wall of a home, convection air currents will tend to move hot and cold air around. The purpose of fiberglass insulation in a wall is to keep convection currents from circulating. The small glass fibers block the movement of air by the convection currents. The “dead” air space is good insulation. Bird feathers, animal fur, and down coats do the same thing. They do not conduct heat, and they prevent convection currents from forming next to the skin. Discussion: Describe the feeling the last time you had a haircut. Long hair traps many air pockets, preventing air circulation next to the skin. Short hair doesnʼt provide that same protection. Discussion: Give local examples of heat transfer by convection. (A well insulated house can be cold if convection currents caused by leaky windows and doors allow convection currents to carry warm air away.) One insidious loss of heat comes when our wood stoves reduce the air pressure in the house. Since warm air must go up the stovepipe for the wood to burn, cold air must come into the house to replace that warmed air. An old timer in Red Devil sealed his house so well that his oil stove couldnʼt burn at all. The fire went out. For air to go up the stovepipe, air must come into the house from somewhere to replace it. If that cold air comes from far across the room as a 5

draft, the whole floor is cooled. Cold air must come in. There is no way to avoid that. It is better to duct cold air up to the wood stove, so the cold air goes directly into the wood stove, not across the floor. Conduction is when heat travels through a material. Examples: • Gloves: heat travels from your hand, through your glove, and away into the outer air resulting in your hand being cold. •

The fins on a chainsaw conduct the heat from the cylinder where the heat is carried away by a strong flow of air.

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When you stand still ice fishing, heat from your feet is conducted through your boots to the cold ice and cold air around your feet. Good boots donʼt conduct heat well at all.

Discussion: What types of clothing are good insulators? Name several. (Down, cotton, wool, all furs.) Which furs are warmer and which ones are not as warm? (Lynx is warm. Land otter and black bear are not very warm.) What types of clothing provide a good windbreak? Name several. (Nylon, dacron, animal skins.) What can you say about damp insulation? (Water is a fairly good conductor of heat. Insulation that has moisture [water] in it will conduct much faster than dry insulation.) Discussion: Think of local examples of heat transfer by conduction. (The metal of our wood stoves conducts heat from the fire to the outside of the stove where it is radiated into the room. In an oil furnace, the heat exchanger conducts heat from the fire and conducts it to the air that is blown into the room. It is important to keep the heat exchanger clean or the transfer of heat will not be efficient. In all engines, excess heat is carried away by either liquid or air and dissipated somewhere away from the cylinder. Activity: 1. Hold a 6” piece of copper wire in one hand. 2. Heat the opposite end of the wire with a match or lighter. 3. How long does it take before you feel the heat? (Not long) 4. Light a wooden match. 5. Hold the far end away from the flame. 6. Is the wood from the match heating your hand? 7. Does wood conduct heat? (Nope.) Activity: 1. Make sleeves of 3-4 different kinds of cloth/fur materials that are long enough to cover a thermometer. 2. Put a thermometer in each of the sleeves. 6

3. 4. 5. 6.

Put each thermometer encased in a different fabric outside on a cold day. Record beginning temperature of each thermometer. Record Temperature of each thermometer at 10,20,30 minute intervals. Which material keeps the thermometer the warmest? Beginning Temperature

Temp. at 10 Temp. at 20 Temp. at 30 minutes minutes minutes

Moose hide Flannel Marten Fur Cotton

Radiation can be imagined as a stream of photons of light. At the same time, it could also be imagined as a series of electromagnetic waves. We see a band of radiant energy and call it light. Below the visible spectrum is infra-red radiant energy that can be sensed as heat by the skin, but not seen with the eyes. Radiant heat, like light, does not need to travel through a material. It can travel through a vacuum where there is no matter, like outer space. Above the visible spectrum is ultraviolet light. Our skin “tans” to protect us from too much ultraviolet. In the spring, snowblindness is caused by overexposure to ultraviolet light. We see only a narrow band of waves, yet radiant energy exists in waves above and below the visible spectrum. Some materials allow radiant heat to pass through, like window glass. Other materials, like a piece of plywood, do not allow radiant heat to pass through.

Activity: Imagine- Step up to a woodstove or campfire. What do you instantly feel? The radiant heat from the fire penetrates your clothing, even your flesh to some extent, literally warming you from the inside out. If you were to turn off the lights and walk towards the wood stove, you couldnʼt see the radiant heat given off by the stove. Could you find its direction by feeling with your hands? What posture would you take to find it? (Probably hands, palm out, swinging back and forth to sense the source of the radiant heat.) Discussion: If you were extremely cold, would you rather stand near a wood stove or a Toyo stove? Why? (The Toyo stove heats the surrounding air. The wood stove heats by radiation. When the radiant heat strikes an object in the room, that 7

object warms up and heats the surrounding air. When radiant heat strikes you, the effect is felt instantly and tends to penetrate our skin.) Discussion: On a summer day, the sun is suddenly obstructed by a cloud. The outside air temperature stays the same, but you instantly feel cooler. Why? (Although the ambient air temperature doesnʼt change, the radiant heat from the sun is blocked.) Discussion: Name the colors of the visible spectrum. (Red, orange, yellow, green, blue, indigo, violet.) These we can see. Radiant heat exists below the visible spectrum. Night goggles, dramatized in movies, allow humans to see infrared radiant heat. Some animals can see into the infra-red band of light and do better in the dark than humans. Has anyone in the class ever used night vision goggles? Discussion: Give local examples of heat transfer by radiation. (Wood stoves, stove pipes, heat lamps in the bathroom, the sun, campfires.) Radiant heat, like light, can be reflected. If we put a wood stove in a white tent, the radiant heat will reflect off the white canvas and warm us from all directions. If we put the same wood stove in a dark green or brown tent, the dark canvas will absorb the radiant heat. The tent will seem cold all the time, even though the wood stove is burning strongly. Survival blankets are made of thin foil covered with plastic. The foil reflects the radiant heat from our body back toward us. Survival blankets are designed to keep our heat in. High quality home fiberglass insulation is foil faced to reflect the radiant heat of the house back into the room. The firefighting packs that Alaskans carry in Lower 48 assignments contain a fire shelter tent. It is simply a shiny aluminum pup tent the firefighter can hide under while the roaring flames pass over. These tents are designed to reflect radiant heat away from the firefighter. Discussion: Now, write in your own words what you think heat is. How does it travel and what importance does it have in our lives, especially in Alaska. List 5 objects you would take with you on a camping trip to stay warm and describe the properties they have which would help you stay warm. 2) Light. Light energy is radiant energy that we can see between the wavelengths of red to violet. Most of our light comes to us from the sun. There are other sources of light: campfires, flashlights, headlights, street lights, the moon, lamps in our homes etc. Discussion: Name sources of light in our communities. (We use lights to see. We use them to signal. We use them to light instruments in planes and cars in the dark. We use them for entertainment, like in a rock concert, and as decoration at Christmas. We use flashing lights to attract attention, like at stores and restaurants.) 8

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How do we use lights to signal? (Turn signals on a truck or car, reflecting metal in the woods, pop up ads on a website trying to direct you towards their product.) How is light important to entertainment? (Discuss how lighting in a movie communicates what is going on… like blue and yellow filters, dark lighting, bright lighting etc.)

To be smart about light is to be smart about lots of things. • Light can be reflected (bike reflector or snow) or absorbed. Most houses are painted light colors to reflect light and keep the room bright. Dark paint makes the room gloomy and makes it hard to see in corners. • Long ago in small log cabins, people hung white bed sheets across the ceiling. The white sheet reflected radiant heat and light. It could be taken down and washed as it got dirty from woodsmoke and soot from candles and kerosene lamps. It wasnʼt an insulator. It was a reflector. Most log cabin ceilings were very dark from smoke and soot over time. The removable white sheet overcame that problem. Discussion: After dark, shine a vehicle light on the reflectors on the cones on your runway. How reflective are they? (Answer: They are tremendously reflective! To an incoming pilot with a landing light on, they almost seem like they have power of their own.) Discussion: Identify other light reflectors. (The moon, the parabolic reflector in a flashlight, light colored paint in homes to keep rooms bright, fuel tanks painted silver or white to reflect heat so fuel doesnʼt heat up and evaporate in the summer.) Discussion: Identify times when we want light to be absorbed. (Paint winter sleds black to melt ice, dark color wings on an airplane to melt frost, the black grease athletes put under their eyes so they can better look into the sun. Snowmachine seats are made of dark colors that absorb light and generate heat to evaporate snow and ice.) Discussion: Why do people tend to get snowblind more on a cloudy spring day than a bright sunny one (On a sunny day the iris is closed and protected. On a cloudy day the iris is open, but the UVʼs come unobstructed through the clouds. The open iris lets the UVʼs into the eye, doing damage. This occurs in the spring because the light is reflected off the snowʼs surface coming at the traveler from many directions. The phenomena occurs to a lesser degree in the summer off the water on a large river, lake or the ocean.) Light can be focused with a magnifying glass, and can generate great heat. Heat cannot be focused in this way. Heat always flows from higher to lower. 9

Activity: On a hot spring day, start a fire with a magnifying glass in sunlight. As light leaves a source, like a bulb, it spreads out and covers a great area. The intensity of the light weakens at a distance. However, laser beams do not spread out. They stay focused. We use laser beams to point at a distance, as distress signals, and, although it is illegal in Alaska to hunt with a laser scope, such scopes are very accurate. 3) Chemical Energy Chemical energy is immensely important because it can be stored for long periods of time and released when needed. We store and release chemical energy constantly. How is chemical energy stored? A chemical bond is formed when atoms and molecules share electrons and tend to stay together thereafter in a “bond.” There are two kinds of bonds: ionic and covalent. Ionic: Ionic bonds are where one of the atoms is real stingy, and hogs the electron(s) to itself. NaCl is an example. The Cl hogs the electron. It doesnʼt share well at all. The Na is left with a + charge because the Cl got the negative electron. Ionic bonds donʼt usually store much energy. Covalent. Covalent bonds are different. With covalent bonds, the atoms tend to share certain electrons. One atom might be a bit hoggish, but, for the most part, they share evenly. Hereʼs the secret: When covalent bonds form, it takes energy to put them together. So when the bond is broken, that chemical energy is given off. All over the world, tremendous effort is made to capture chemical energy, store it, and put it to use at the exact moment it is needed. Other forms of energy like electrical energy, light energy, kinetic energy (motion) and, to some extent heat energy, are all available for brief moments. It is very difficult to store these forms of energy for a considerable amount of time. Covalent bonds store chemical energy for a long, long time. That is the ultimate value of chemical energy. Chemical bonds can hold large amounts of energy to be released at a precise moment, whether it is gunpowder waiting for the pull of the trigger, or diesel fuel waiting all winter in the tank to be released at just the right moment to meet your need when you flip the light switch.

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Traditionally fat animals were more highly valued than lean ones as the fat was a rich food for humans and dogs, and was used in lamps to light homes. Before petroleum was taken from the ground and refined, animal fats like whale oil were used across the world for lighting. In the 1800ʼs Alaska was a major destination for whalers seeking oil to illuminate whole cities. Activity: Get bear or moose fat. Cut about 2/3 cup into small pieces. Render it in a frying pan, just like bacon. Make a lamp out of aluminum foil and a slim wick out of twisted paper towel. Dip the wick in bear fat, then pour the fat into the lamp and embed the wick in the fat. Light it. Trim the flame by pulling the wick out of or pushing it into the fat in the lamp. This will not trip the smoke alarm if windows are open and the flames arenʼt allowed to burn for too long. Today we extract the energy of covalent bonds from the ground, refine the oil, and produce fuels of all kinds: diesel, jet, auto, aviation etc. What is the Alaska pipeline all about? It is about pumping covalent bonds out of the ground, sending them down the pipeline (TAPS), then to big ships. It is about those ships bringing the crude oil that contains the covalent bonds to the refinery, and about people releasing the energy of those covalent bonds in a steady stream as they drive down the highway or generate power to watch a movie or charge a cell phone. The covalent bonds of the Alaskan crude oil were stored in the ground for millions of years, yet have recently become available to do work for us, driving pistons in our small engines, turbines in jets, and furnaces in our homes. What is hunting all about? It is about seeking covalent bonds in the form of a moose, caribou or other animal, harvesting and storing those covalent bonds for the day when they go into our cooking pot. Fishing is storing covalent bonds in the meat of the fish for the exact moment we become hungry and tired. That is huge. When meat or fish rot, the covalent bonds are broken down, and the food value of the meat is released. Bacteria use that energy, taking from us the opportunity to use it for ourselves.

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All living things are totally dependent on covalent bonds, the energy they store up and the ability to release that energy at just the right moment. If the rabbit had to wait for the release of chemical energy in order to run away, there wouldnʼt be any rabbits left. No, the rabbit eats willows today, and is able to instantly spurt away at the sight of a hawkʼs shadow tomorrow because of stored chemical energy. It takes energy to form covalent bonds, and energy is given off when they are broken. Acetylene, which is used in cutting steel, gives off tremendous heat energy when it is combined with oxygen because it has a triple covalent bond. Propane only has a double covalent bond and is not able to get as hot. Where does the energy come from to make your four-wheeler run? From the covalent bonds waiting for the exact moment when you punch the throttle. Where does the energy come from so you can play basketball? From the covalent bonds releasing energy from the food you ate for breakfast, lunch and supper. Where does the energy come from to run your cell phone? When you charge the battery, chemicals combine in covalent bonds. When you talk on the phone, the covalent bonds are broken, giving off the electrons necessary to run the phone. Our lives are built around chasing covalent bonds, storing them and releasing them at the right time. You eat bread and get energy to go hunting. The moose eats the willows to get his energy to run away from you. When we eat the moose we get secondhand willow energy. When a house burns down, the release of covalent bonds has gotten far out of control. All the energy stored in those bonds is released in a very short time to the destruction of our valuable possessions. Discussion: Name 10 items that we ship into our town or villages that contain energy from covalent bonds. (Stove oil, gasoline, AA batteries, all forms of groceries…) Name 5 items that we move around our town or village that contain energy from covalent bonds to be used at a later time. (dried salmon, moose meat, ammunition, whitefish, cordwood…) 12

Wood can sit in a woodshed for two years and not lose much energy at all. But, if that wood is lying on damp ground, much of the chemical energy will be lost as the wood rots. Rotting is a very similar process to burning, but is much slower. Everyone knows that rotten wood doesnʼt have as much heat as healthy dry wood. Salmon strips that you jarred in July sit in the pantry and release the chemical energy the moment you choose. The berries you picked last fall give you the pep to go ice fishing. Discussion: How do animals store chemical energy? (They store chemical energy short term as sugar in the blood, long term as fat. Fat has many covalent bonds. Bears must store enough fat in the fall to get through the whole winter. Some birds, like camp robbers and chickadees store food [chemical energy] in different hiding places behind tree bark.) Mice store seeds for winter as well. Discussion: Why are birds limited in storing chemical energy as fat? (If they get too fat, they are too heavy to fly. Have a local expert tell of the types of ducks that experience difficulty taking off.) Activity: Have a local expert relate the annual cycles for bull and cow moose or caribou when they are fat and when they are lean. Bulls and cows donʼt follow the same patterns of fat/lean during the different months. (Bulls fatten during the summer and lose all the fat during the fall rut. They are lean during the rest of the year. Cows fatten in the spring before calving, and get lean while nursing the calves. They are lean the rest of the year unless it is a barren cow.) Activity: Graph the input of food resources into your village from subsistence activities over a 12 month period. On a scale of 1-10, estimate how much energy each represents. You will see that food comes in very specific times. There are months when very little energy is available from subsistence and months of great abundance. Now graph the estimated consumption of energy. You will see that it is somewhat consistent. This is the essence of subsistence living. Gather during times of plenty and store for times of lack. The supply is extremely variable and the demand is fairly constant. Activity: Now have each student record and then graph the demand for fuel in their home over a period of 12 months. When is the most gasoline used? Stove oil? Wood? When does the supply arrive? The demand is somewhat predictable. The supply is extremely inconsistent. Subsistence could be described as the pursuit of covalent bonds and the challenge to store them. Spend time discussing the storage methods for all the energy sources. Drying salmon, freezing moosemeat, jarring berries, getting a woodpile, filling the village fuel tanks by barge etc.

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Forming the covalent bond. It takes an input of energy for atoms to combine with a covalent bond in a higher energy level. That energy is released when the bond is broke into a lower energy level.

Threshold. The question arises, what keeps that covalent bond from breaking and being released over time? And from that question: • What keeps the energy in gunpowder from being released before we pull the trigger? What would happen if we pulled the trigger, the primer fired and the bullet barely made it out of the gun barrel because the energy had leaked out while the cartridge was on the shelf? • What keeps the energy in the covalent bonds of gasoline and diesel fuel from being released while the fuel sits in the tank? (Actually, diesel stores well, but gasoline does age within a few months of the refining process.) The answer to the above questions is best described with a graphic. For the covalent bond to break, and for the energy to be released, a small amount of energy must first be put into the bond to raise the energy level and break it and then to release the large amount of chemical energy stored. In the case of using a match to light a campfire, a small amount of heat must be put into the match by friction. This causes the match to rapidly oxidize (burn,) giving off heat. That heat is enough to ignite the kindling, which ignites the wood for the campfire. So, the covalent bond is safe from being broken until enough energy is put into it and when it does break, it 14

releases the stored energy. Itʼs like the energy has to go up and over a hill before it can be released. That hill is called the threshold. When wood rots, the energy is released by bacteria, and rotten wood does not have the same amount of stored energy as good standing dry wood. Bacteria get the wood fibers up and over the threshold. Gasoline is safe from ignition until energy is inputted by the sparkplug. Then the covalent bonds of the gasoline are broken and great heat is released. That heat creates a chain reaction that causes the covalent bonds of the rest of the gasoline molecules to get up and over the energy hill, and release all of their stored chemical energy.

Threshold. • Some covalent bonds have a high threshold like wood. You have to put a lot of energy into them to break the bonds and release the stored energy. • Some have a lower threshold like butane in a lighter. Amount of energy released. • Some covalent bonds release great energy when they are broken, like acetylene. • Some release a little bit of energy like potatoes shifting from sugar to starch. Speed of release of energy • Some covalent bonds release energy very suddenly, like dynamite. • Some covalent bonds release energy slowly, like glowing charcoal. 4) Kinetic Energy (KE) Kinetic energy is the energy of motion. Potential energy is when an object is in a position to give off kinetic energy. For example, a river is a huge amount of water in kinetic motion. It would take a great force to stop it. It could give a great amount of energy if we were ingenious enough to harness it, like turning the water current in our rivers into electric current in our power lines. Sound is a form of kinetic energy, as it represents the motion of waves in the air.

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A glacier has potential energy. It isnʼt moving, (or is very slowly) but the water is in a position to give kinetic energy should it melt and flow downriver. So, potential energy is kinetic energy waiting to happen. A boy exerts kinetic energy as he goes up a hill. While stopped on the top of the hill he has potential energy. When he slides back down the hill he releases the potential energy back into kinetic energy.

We take advantage of the kinetic energy produced by four wheelers, outboards, airplanes, snowmachines etc. We are very dependent on the kinetic energy of power tools and vehicles. If we crash our snowmachine into a tree, we soon realize how much kinetic energy was available. The kinetic energy is released to crumple the machine and maybe us too. If an airplane tries to land with too much kinetic energy, it will have problems. The pilot must make sure to land with just the right amount of kinetic energy. Too much and the plane goes off the end of the runway. Not enough, and the plane is in the weeds short of the runway. Piloting a plane is all about converting potential energy to kinetic energy and managing both of them. It takes kinetic energy for an eagle to climb to a certain altitude. That kinetic energy is potential energy that is stored as the eagle soars. The potential energy is released and converted back into kinetic energy when it dives to strike the rabbit. You expend kinetic energy to set a trap. That energy exists as potential energy until an animal steps on the trigger. The potential energy becomes kinetic energy when the trap jumps quickly to hold the animal. Activity: Name five objects in the town or village that have, utilize or create kinetic or potential energy. (Any kind of engine, water pump, drill, circular saw, chainsaw… anything moving.) Whether we are moving wood from the woodlot to our homes, or just riding around to leave the summer bugs behind, kinetic energy is a huge part of our daily routine. To understand kinetic energy is a great help. To not understand it could be a great ouch! Kinetic energy follows three strict laws. 1) Inertia 2) Force= mass x acceleration, F=ma. and 3) action=reaction. (We will study Newtonʼs three laws in another lesson.) Discussion: Give an example of Action=Reaction. (Kick of a rifle, the paddle goes backward and the canoe goes forward.)

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Discussion: Give an example of inertia. (You hit a snag with your boat. The boat stops quickly and everything in the boat goes forward.) Discussion: Force equals the mass of the object times the acceleration: F=ma. Give examples (A bigger hammer can hit with more force than a smaller hammer. A faster swing of a baseball bat will hit the ball farther than a slow swing.) One of the biggest problems of converting kinetic wind energy into electricity is there is no relationship between the availability of wind and the demand for electricity. The wind might blow terribly hard in the middle of the night when people donʼt need electrical power as much as during the day. Activity Chart the availability of wind in your community for a month. Is it fairly constant at specific times of the day? Is it very sporadic? Compare the supply of wind with the electric demand by your community. Graph them both. In Kodiak, much of the local electricity is generated by wind and hydro-power working together. When the wind dies down, water is released from the hydro dams. In that way, water power is a wonderful backup for inconsistent wind power. If a diesel generator had to stop and start to back up the irregular kinetic energy of the wind, the generator couldnʼt keep up with the spikes and drops in wind power and match them to the demand of the area. Battery units attempt to bridge the gap between the times of high wind output and times of high electrical demand. 5) Electricity. Electricity seems like magic. 150 years ago, electricity was a curiosity in science labs, but had little to do with the common man other than the observation of lightening. Now we canʼt go a day, perhaps even an hour without itʼs benefit. Cell phones, internet, GPSʼs, movies, video games, texting, home heating all require precise amounts of electricity directed in very accurate ways. There are only four known forces in the universe: gravity, two subatomic forces, and electromagnetic. The fact that science can name them does not mean that we understand them. However, we can describe how they work. Electromagnetic force causes the flow of electrons down a wire. Electricity is a charge that can pass through a conductor (like copper wire) and does work as an electric current (like toasting your bread or giving spark to your outboard motor.) For easy understanding, we think of the flow of electricity like water flowing in a pipe.

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The outstanding aspect of electricity is that it can be converted into the other forms of energy quite easily. A boom box turns electric energy into stereo sound. An electric motor cuts a 2x4. Electric energy lights our rooms, ignites stoves and furnaces, cuts hair, cooks food and pumps heat out of a refrigerator. These all represent electric energy changing to another form of energy. Electricity works by very predictable laws, and can be controlled and directed very precisely. Computers, the internet, aviation instruments, engine magnetos, snowmachine/outboard/wheeler/chainsaw engines all are the direct benefit of being able to control electricity. Memory on a computer chip has to do with storing a huge number of tiny electric signals in an incredibly small space. One hundred years ago, both Native and non Native people understood heat, light, motion, and the release of chemical energy. The mastery of electrical energy has brought us from horse and buggy, from canoes and dog teams, to the complex modern day. Whole careers are based on understanding and manipulating electricity. If knowledge is wealth, then knowledge of electricity is extreme wealth. Safety. Two safety features in home wiring systems are breakers and GCFIʼs. When too much electricity flows down a wire, and the wiring becomes dangerously hot, the breaker snaps off. It is simply a switch that turns off in response to high heat. This keeps our home from burning down when there are too many appliances on one circuit. A GCFI, ground current fault interrupter, is different. If electricity goes out a wire, but goes to some ground rather than coming back through the circuit, it instantly trips the GCFI. If the electricity goes out and flows into your body rather than back through the circuit, the GFI instantly stops the current. Story says it will break before the electricity gets to your heart, but that sounds like myth. However, it will trip long, long before the wire gets hot enough to trip the 18

breaker. As soon as the current goes out and doesnʼt return, the GCFI switches to off. Many circuits have a GCFI as the first outlet. Outlets following in that circuit will also be protected. If either the breaker or GFI are tripped, it is very important to find out why, and not just reset either of them. They do not trip by error. Activity: Every building has a breaker box. Find the breaker box in 3-5 buildings. Identify the number of amps each breaker is designed for. Find the breaker box in the school or other building. Note that each circuit has a breaker, mostly 15 amps, and is labeled as to the part of the building or function it serves. Ask a local expert why some breakers are held together by a bar so when one trips both of them trip. Activity: Find GCFIʼs in the school. Find them in the clinic, in homes and public buildings. All circuits that involve outlets where people can get a shock should have a GCFI in the first outlet to protect that whole circuit. Direct Current and Alternating Current. Electricity travels at the speed of light. Direct current goes out one wire and returns by a second wire. Alternating current is when the electricity alternates out and back on each of two wires 60 times each second.

Direct current is used in most flashlights and simple circuit boards. Direct current canʼt travel far through a wire without considerable voltage drop. Electricity travels to computers as alternating current, but is converted to direct current to perform the exact computer functions. Batteries and solar cells produce direct current. Almost all precise electronic devises run on direct current that has been converted from alternating current. Alternating current travels from the local generator into homes and is used as alternating current because it can travel long distances 19

without great voltage drops. Most electric motors run on alternating current. All hightension wires are high voltage AC. The differences between and uses for DC and AC current and how to convert one to the other are the topics for another lesson. Activity: Identify 3 appliances that use alternating current. (Coffee pot, washing machine, fluorescent light) Identify 3 electrical units that use direct current. (Flashlight, headlight on snowmachine, laptop computer. Some materials conduct electricity well, like copper, aluminum, silver etc. Other materials donʼt conduct electricity well at all, like plastic, glass and rubber. Activity: Get a wall outlet that isnʼt installed. Find the parts that conduct electricity and those that insulate. Test them for conductivity with an ohm meter. Do the same with a wall switch. How does the switch work? Look at a circuit board. identify the parts that conduct electricity well, those that do not, and those that direct or control the flow of electricity (the elements soldered into the circuit board.) You can test conductivity with the ohm setting on a multi-meter. Find 5 items in the class that conduct electricity and 5 that do not. What do they have in common? (Generally, metal conducts electricity and plastic does not.) Electromagnetic. Every electric current is surrounded by an electromagnetic field and vice versa. Their relationship is so close, the word "electromagnetic" describes how they work together. If a magnet is spun with force in the midst of a properly wound coil of copper wires, the electromagnetic force of that magnet causes current to flow in that coil and outward to do work. That is a generator. If a current comes into a properly wound coil of wires, the electromagnetic force chases a magnet spinning in the middle which turns with force to do work. That is a motor. In both the generator and motor, the outer coils stay motionless, and the magnet in the middle either drives or is driven by electromagnetic force. The only difference is one is the driver and the other is the driven.

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There are two kinds of magnets, permanent and induced. A permanent magnet is just that, it is always acting as a magnet. In an induced magnet, the iron around which the coils are wrapped causes the iron to be a magnet as long as electricity is flowing in the coils. When the electricity stops flowing, the iron stops being a magnet. Long ago, electric motors and generators had a permanent magnet spinning in the middle of the coils. In the case of the generator, when the magnet was spun, the electromagnetic force drove electrons down the wire from the coils. It was discovered that a generator was more efficient when the magnet spinning in the middle was an induced magnet. So, generators were changed to use an induced magnet and that generator was called an alternator. The advantage was that it could generate more electricity at lower rpmʼs. The disadvantage was that it required some power from the battery to induce the magnet. A vehicle with a completely dead battery could not be jump-started. Most recently, high tech rare earth permanent magnets have been developed that are extremely efficient. So, many of the new generators, like those used in wind generation, are no longer alternators, but have converted back to induced magnet generators again. Technology continues to change the playing field. This points to the need for copper, aluminum, zinc and other rare earth minerals to create efficient energy generation. Alaska is fortunate to have many of the mineral resources to provide the nation. Mining has always been part of the Alaskan economy, and is more important now than ever before. The simple changing of forms of energy from kinetic, to magnetic to electric and then back from electric to magnetic to kinetic has caused much of the technology that makes modern life so amazing. It is as if we instantly transfer kinetic motion long distances. The fuel in a village generator drives a piston that turns a shaft that spins a magnet in the midst of a coil of wires forcing electrons down a wire. The mechanic triggers his grinder, and the electrical current causes an electromagnetic force that drives a magnet that spins a shaft that drives grinding wheel that grinds a rusty bolt. Absolutely amazing! We take advantages of electromagnetic forces constantly in villages. Every engine has a “magneto.” Why is it called that? Because it has a magnet embedded in the flywheel. When the magnet spins past the copper wires of the primary coil in the stator of your outboard, four wheeler, snowmachine or chainsaw, the electromagnetic force of the magnet pushes a flow of electric current through the copper wires of the primary coil. Activity: Expose the magneto on a working engine. Measure the distance between the magnets on the flywheel and the 21

arms of the coil. Use a feeler gauge. If they are too close, they will wear on each other. If they are too far apart, the induced spark will be weak. If you can fit a matchbook cover between them the distance is a bit too big. The electric current from the magneto doesnʼt have nearly enough voltage (pressure) to jump the sparkplug gap in the cylinder. So, the current from the magneto flows immediately to the secondary coil where there are actually two coils, one inside the other. There are no wires touching between them. It all works by electromagnetic force. The primary coil delivers a high amperage, lower voltage current to the inside coil. The electromagnetic force of that current induces a current in the outside coil. However, the copper wires in the outside coil are wound differently. The current in the outside coil is a low amperage but very high voltage that races to the sparkplug at the speed of light. That current has thousands of volts, enough to jump across the sparkplug gap in the cylinder. At exactly the right moment, the spark jumps and ignites the fuel. At full throttle in a snowmachine, this happens 5,000-6,000 times a minute, or 80-100 times a second! Many chainsaws turn 50% faster than that! Timing is important. If the plug sparks too soon, there will be a damaging backward force against the pistonʼs motion. If it sparks too late, all the fuel wonʼt have time to burn on the power stroke. Power and fuel will be wasted. Activity: Look up the proper sparkplug gap for 4 different gasoline engines. Are they the same or different? Usually the gap depends on the compression and the voltage from the secondary coil. If the gap is too close, it will not expose enough spark to the fuel. If the gap is too far, the spark wonʼt jump at all. With a feeler gauge, check the sparkplug gap in the engines for which you looked up the info. Without electromagnetic forces, our village lives would be totally different. We would be without the simplest engines that now make our lifestyle so convenient. We would be walking, snowshoeing, paddling, sawing wood by hand and cleaning clothes with a scrub board. Our village generators would not exist. We would be like our grandparents, using kerosene and Blazo to light our homes. Energy systems and technologies worldwide are becoming more efficient and quieter to improve the quality of life in the most remote villages and the largest cities. It is a fascinating study. 22

The only difference between a generator and a motor is that one drives and the other is driven. They both work in the same way: a magnet is spun in the middle of a coil of wires. Electrical energy in the form of electromagnetic force drives countless appliances in our everyday lives. Measuring electricity. In the study of electricity, there are four important terms: volts, amps, watts and ohms. Think of electricity as being like water in a pipe. Volts = pressure Amps= gallons. Watts = volts x amps. The quantity of electricity under a given pressure= how much “power” is used. Ohms = the resistance to the flow of electricity, like rust and junk stuck in a water pipe, slowing the flow. Our electric bill comes to us in kilowatts (1000 Watts) per hour, so, knowing how to figure watts from the information on the back of an appliance is vey important to understanding how to reduce our electric bill. The electricity coming from wall sockets in the United States provide 120 volts. Activity: If an electric drill uses .1 amps in a circuit that runs on 120 volts, how many watts does it use? W= V(A) W= 120volts x .1amp or 12 watts. If a compressor to drive a nail gun uses 10 amps, how many watts does it use? Watts= 120 volts x 10 amps or 1200 watts.

Again, figuring how much each costs to run is important if we want to reduce our electric bill. If electricity is $.50KWH (kilowatthour) and a circular saw uses 10 amps, lets figure how much it costs to run the saw for an hour. 10 amps x 120volts = 1200 watts or 1.2 kilowatts. If the price is $.50 an hour then 1.2 kwh x $.50 = $60 to run it for an hour. Activity: On every electrical appliance there is information that tells how many amps are used at how many volts. Look at TVʼs, video games, light bulbs, tools, toasters, egg-beaters etc. Record the volts and amps, and compute the watts. Find the cost of 1 KW electricity (1000 watts for an hour) in your community. Multiply that cost times the amount of electricity used by those appliances. Find the cost of running each one for an hour in your community. Discussion: How did people long ago use heat energy? Light energy? Motion? Chemical energy? (Heat: campfires and home fires kept people warm and cooked their meals. Light: people used bear fat lamps to light their homes, and used the light from the moon and 23

stars to navigate and predict the weather. Motion: people used kinetic energy in the form of bows and spears to hunt. They used canoes to migrate from one place to another. Chemical: people used the chemical energy stored in bear, whitefish, caribou and other fats to light their houses, and used the chemical energy stored in wood to heat their homes as well. They used the chemical energy in berries, fish eggs and other natural foods to keep alive and warm.)

Lesson 2: Converting One Kind of Energy to Another If the energy of motion just stayed as motion, we would be limited. But we can change it to other forms of energy. If the energy of light stayed as light, we would be limited, but in a solar panel we convert it to electricity. We can take that electricity, store it as chemical energy in a battery, then release it after the sun goes down. The chemical energy of the battery gives electrical energy, which gives us back the light during the dark hours. The chemical energy in diesel fuel is converted to kinetic energy of motion in the generator. How? The chemical energy of burning fuel causes expanding gasses that drive the piston. Kinetic energy of the piston drives an electric generator that converts the kinetic energy to electricity, which comes to your house to be converted to light or whatever use you decide to put it towards. So, in the simple process that goes on in your town or village 24/7, different forms of energy are being converted to many other forms of energy. Efficiency. Energy "efficiency" describes the flow of energy put into a system and what comes out as a result. The "law of conservation of energy" says that energy cannot be created or destroyed, and that the total amount of energy in any reaction stays the same. As we try to use energy, it is transformed into some forms that are useful to us and other forms that are not useful. When most of the energy goes to the purpose we want, we say the system is “efficient.” Burning fuel gives off energy we can use to move a machine, but some of that energy transforms into heat that may even damage the machine. If the cooling fins on a fourwheeler and the oil cooler are covered with mud, the engine could overheat and cease up. We can reduce waste and save money if we study how all the forms of energy flow in and out of our reactions. 24

In some large power plants, 95% efficiency is possible!!! On the other hand, our common use of burning gasoline in cars is more like 25-30% efficient, and often much less. The idea of efficiency can be applied in a huge range of systems, from getting better gas mileage in a snow machine to heating a home with less wood or oil. When one form of energy is converted to another, there is always a loss. When a diesel engine converts the chemical energy of fuel to kinetic energy, it is only 60% efficient. 40% goes to creating undesirable heat and sound. When the generator converts the kinetic energy of the diesel to electricity there is another loss in the form of heat. When the electricity passes through the wires to your house, there is again a loss in the form of heat. When electricity is converted to light in a bulb, only 20% of the energy becomes light. The rest is turned into heat. There is a string of losses just to get light into your room, most of those losses being in the form of heat. When you put wood in your stove, less than 60% of the potential chemical energy is released as heat into the house. Most of the loss is the result of unburned gasses going up the stovepipe. Newer wood stoves seek to burn waste gasses and increase efficiency, but most seem to have so many contraptions inside the firebox there is scant room for wood. A campfire converts chemical energy mostly to heat, light and a little sound. Much of the energy of a campfire is lost as we heat the whole outdoors rather than ourselves. A blue flame indicates efficient combustion of fuel. A yellow or red flame indicates inefficient combustion. Most propane and Toyo/Monitor stoves burn with a blue flame. Seldom does a wood stove burn with a blue flame. Discussion: What systems in nature appear to be extremely efficient? (water cycle) Which seem wasteful? (Forest fires. Out of thousands of salmon eggs, only one mature salmon returns to spawn.) How efficient is the whole of nature? (There are cycles, and nature seems more resilient than efficient.) Energy Trail Follow the energy trail backwards. Your four wheeler speeds down the road. That is kinetic energy. What was the energy trail that led up to the road experience? The kinetic energy of motion came from the chemical energy in the fuel, which, in theory, came from the chemical energy of smooshed dinosaurs, which came from the chemical energy from those dinosaurs eating plants millions of years ago, which got their chemical energy 25

from the light energy of the sun. Activity: Draw this energy trail. Draw the energy trail for any activity in the village. Almost all trails lead back to the sun, either in recent or distant history. But there are a couple of loops. It took electrical energy from the engine to give enough electric current to cause the plug to spark at the right instant. It also took a great amount of chemical energy to create the kinetic energy to freight the fuel to your village. There are more loops to consider. It also took a lot of chemical/heat, electrical and kinetic energy to refine the crude oil into gasoline that burns in your four wheeler. You have moose meat for supper. Later you go play basketball. Give the energy trail for your basketball activities. Discussion: (You get kinetic energy from the chemical energy of the moose meat. The moose got his chemical energy from the willows. The willows got chemical energy from light energy from the sun.) Activity. Trace it back and go a little wider. Start with the stored chemical energy in the rifle cartridge that shot the moose. List all the forms of energy that were involved or related to your basketball activity. Discussion: You pull the trigger. The kinetic energy of the firing pin creates heat in the primer which creates enough heat to ignite the gunpowder. The gunpowder expands causing kinetic energy of the moving bullet. The bullet expends its kinetic energy doing damage in the moose. Then your family expended kinetic energy to butcher and haul the moose to your home. Chemical energy was used in the machinery to do so. Light energy was used while hanging the moose in the smoke house etc. Your mom expended kinetic energy to cut it up. The chemical energy of propane was converted into heat energy to do the cooking. Thereʼs too much energy moving around to keep track of! But the point is clear. Energy is constantly being converted from one form to another. Try one more. Your community gets some of its electricity from wind power. Your are reading a book. Follow the energy trail for the light necessary to read the book after sundown. Discussion: (The light energy was converted from electrical energy which probably came from the chemical energy of a battery which came from the electrical energy of the wind charger. The kinetic energy to drive the wind charger came from the kinetic energy from the wind, which got itʼs kinetic energy from the uneven heat energy on the earth, which got itʼs energy from the light energy from the sun.)

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If we do this often enough, we will almost always end up with the sun as the source of all energy. The only exception to this might be geothermal energy taken from the core of the earth, and that too probably originated from the sun.

Alternative Energy A message to young village people: As we study energy, we see that life in the Alaskan bush has changed drastically in the past fifty years. There is a great need for young people who live in the bush to become aware of the changes taking place, and learn how to apply the positive aspects to our subsistence lifestyle to those changes. Every year new technology and ideas come along that might provide us with savings and help us return to self-sufficiency. The high cost of energy in the form of electricity, fuel oil, propane and gasoline has caused a crisis. The science in this unit can be used to inspire communities to find solutions. There are three sources of rural energy dependence: 1. Heating of homes and village buildings, including schools. 2. Electricity for homes and village buildings, including water and sewer facilities. 3. Transportation with planes, trucks, fourwheelers, outboards and snowmachines. There are two ways to help in each of these: 1. Improve what already exists. 2. Develop something completely new. Activity: Identify one part of your communityʼs energy needs. Suggest one alternative or way to make it more efficient. Some things cost money up front, but have a short payback time. How long do you think it would take to payback the cost of your idea? Efforts to find renewable energies, utilizing waste, and improve efficiency have had successes and failures throughout the state of Alaska, but mostly on the level of the government doing it to or for the people, not on the level of individuals trying something new, making it work, and spreading the word. Tok biomass is a highly successful project that was funded by the State, but driven by intelligent determined local individuals. Alternative energy is a subject that could and should involve everyone in rural communities. U.S. Congressman Don Young spoke at the Rural Energy Conference (April 2013) encouraging a very high goal. He would like all rural communities to become totally independent of expensive diesel fuel. Rural energy needs are huge. The opportunity for innovation is too. The possibilities for turning the power of our rivers into usable electric power are exciting. Every day far more free energy flows past our villages than several diesel generators could ever 27

produce. At the same time, thirty percent of heating and electricity in the modern country of Finland come from the same kind of peat we have all over western Alaska. McGrath has enough peat to heat and electrify the community for 300 years, yet power generation is dependent on imported diesel fuel. Improvements you develop can influence other villages, go to the rest of the state and possibly to the world as a model. Alaskan villages have great resources and freedom not available to urban communities. When we want a tree, we go get it. When urban people want a piece of lumber they have to spend big money, wrestle with hearings, meetings, permits and nonsense we donʼt have. Urban obstacles kill creative energy and thoughts. Rural areas have freedom and opportunity to make things happen. Here are a few specific projects around the State for research (this is changing quickly everywhere): • Biomass: Tok and Napaimute • Wind: St.Paul and many western villages • Diesel/wind hybrid systems: Emmonak, Chevak • Solar: Ambler, Galena • Geothermal: Fairbanks/Chena Hot Springs • Heat Recovery from diesel gensets: McGrath, many others (can be everywhere) • Efficient home construction: Anaktuvik Pass • Tidal ocean: Yakutat • River generators: Eagle, Nenana Many developers think that diesel will be the backbone of most village power systems for some time to come. If this is the case, those systems need to be operating at their highest efficiency. Renewables or other systems can be added to supplement that power. Later villages may be able to wean completely from diesel. Rural people have the ingenuity and knowledge of local resources. Many projects do not require high maintenance or specialized skills, and can be handled locally. Special school projects can get the community thinking. The opportunity to turn a village problem into a village opportunity are right in front of us. Success starts with a new idea, not necessarily a government grant. All the energy we need to light and heat our village homes and buildings is right around us. We must find ways to convert the kinetic and chemical energy of our rivers, wind and local biomass into that versatile form of energy we all come to love: electricity. This is an exciting new challenge that could create careers and economy, save many of our villages from high energy costs and the outmigration of our families to the cities. Activity: Research one of the above projects in the State of Alaska. What was the original intent? How did it change over time? What was the final project? What were the problems and obstacles? 28

Introduction to the Math of Physics Study Sheet.1 for Students In Physics, we try to describe events as precisely and simply as possible. As it turns out, mathematics helps us do this in very powerful ways and becomes like a language of science. While the math may seem to get complicated, remember that this is all an attempt to make it simple and possible to understand for everyone from any language or culture! In this attempt then, we have many common symbols and formulas used worldwide. Asking questions when you start to have confusion will be your best way to achieve a good understanding, so insist that you get clear answers to your questions! Throughout this unit we will give symbols and formulas in parentheses behind the words to help you remember them. Here is a Key for some with definition first, then symbol then units: (a more advanced key for all symbols can be found at: collegeboard.com/prod_downloads/ap/students/physics/info_equation_tables

Force (F) Newtons (N) mass (m) kg, grams, lbs, etc. distance (d) or (s) displacement or distance; meters, inches… time (t) sec, hrs… velocity (d/t) mph, centimeters per second… acceleration (d/t/t) or (d/t2) centimeters per second squared energy (E) Joules (J) Kinetic energy (KE) Joules Potential Energy (PE) Joules velocity of light (c) for "constant", always the same work (W) Joules (J) or Newton meters Nm power (P) Watts (W) current (I) amperes, amps (A) charge energy (V) volts resistance (R) ohms (Ω) initial velocity vi or v0 final velocity vf or v1 “change in” Δ delta gravity (g) d/t2 weight (mg) momentum (mv)

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Helpful Formulas: v= Δd/Δ t

a=d/t2

F=ma

P= W/t

V=IR so I=V/R W=Fd

KE=1/2mv2

Also remember that fractions are simply ratios or relationships. When we say, "miles per hour" or "how many miles in an hour" we relate miles to hours and to make it easier we say mathematically miles/hour. That divided sign just means "per", but we can manipulate it later in math equations to play with other relationships.

So if we say you sped up from 10 miles per hour to 50 miles per hour, we know your "initial" or starting velocity and your "final" velocity. To write this mathematically to make it shorter and simpler we write: v0 = 10mi/hr. and, v1 = 50mi/hr. Already we have some math power. If we want to know how much you gained in speed we can subtract: v1 – v0 = 50mi/hr. -10mi/hr. = 40 mi/hr. NOTE: This is just common sense, but already is looking like cool physics! Remember to keep going back to your simple understanding and just translate the math symbols back into words or match the words to the symbols. Lets extend this more to our concept of "acceleration". From the example above, we know that you gained 40mi/hr. overall, but we don't know how impressive that would be until we ask, "How long did it take to gain that 40mi/hr.?" If it took all day, we would not be very impressed! But if you did that in 2 seconds, wow! We call the change in velocity "acceleration". If you increase velocity, acceleration is positive (speeding up), decreasing is negative or "decelerating" (slowing down).

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Suppose in our example above, it took you 1 hour to increase that velocity. How can we express it mathematically? 1. We want to say," you sped up from 10 miles per hour to 50 miles per hour in one hour." Or the velocity changed from 10 miles per hour to 50 miles per hour in one hour. 2. Mathematically, the change is represented as before: 40mi/hr. But we include the "in one hour" in the same way to say 40mi/hr./hr. 3. Now we have 40 miles per hour increase per hour, or 40 mi/hr2. If we made that increase from 10mph to 50mph in just 2 seconds (that is ≈0.00056 hrs.), we can see how much faster our acceleration is: 40mi/hr./0.00056 hr. = about 72,000mi/hr.2!! Now our math symbols make things much more interesting. We understand that acceleration is a "quadratic" and it has a squared time expression. When we think about how the distance changes, we will need to consider a much more radical change than simply additive or increasing arithmetically, but now it is increasing exponentially as a function of time squared or two times (one being in the velocity, and one being in the time of the change of velocity).

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Energy Unit: On Efficiency Study Sheet.2 for Students DIRECTIONS: Read and discuss the following. Think about and answer the questions on a separate piece of paper. Energy "efficiency" describes the flow of energy put into a system and what comes out as a result. The "law of conservation of energy" means that energy cannot be created or destroyed, and that the total amount of energy in any reaction stays the same. The key concern is that as we try to use energy, it is transformed into some forms that are useful to us and other forms we did not intend or find difficult to use. 100% efficiency means all the energy put in gets used coming out. Burning fuel gives of some energy we can use to move a machine, but some of that energy transforms into heat that may even damage the machine. If we study how all the forms of energy flow in and out of our reactions, we can learn to use the forms usually considered "waste" and make the entire system more efficient. 95% efficiency is possible even in some large power plants! On the other hand, our common use of burning gasoline in cars is more like 25-30% maximum efficiency, and often much less! The idea of efficiency can be applied in a huge range of systems, from thinking about how to get better gas mileage in your snow machine, to how to make the impact of the whole human race on the planet more useful.

COMPELLING QUESTIONS 1. What systems in nature appear to be extremely efficient? 2. Which seem wasteful? 3. How efficient is the whole of nature?

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Experiments EXPERIMENT #1 Sensing heat. This is a simple and thought provoking experiment showing how we sense heat. Materials: • Three wash basins. • Hot water from the tap, which should be hot to the touch, but not so hot it burns the skin when immersed. • Cold Water. Water with snow or ice is best. • Timer Put hot water in one wash basin on the left. Put icy water in a wash basin on the right. Put room temp. water in a wash basin in the middle. Put one hand in the hot water and one in the icy water. After two minutes, or as long as the student is comfortable, put both hands in the room temp. water. What does the hand that had been in the hot water feel? (Cold) What does the hand that had been in the icy water feel? (Hot) How can this be? (Hot and cold are relative)

Heat Math •You heat with both wood and oil. If a gallon of stove oil costs $8, and your home used 43 gallons last month, how much did it cost you to heat your home? •A cord of dry spruce cost $250, and a cord of birch is $300. A cord of spruce has 12 mbtu/ cord. A cord of birch is 21 mbtu/cord. Which is the most economical /mbtu to buy? •Stove oil is .14 mbtu/ gallon. If both wood and oil burned 100% efficiently, which is the more economical? A cord of wood is 8ʼx4ʼx4ʼ. How many cubic feet is that? If a sled can haul wood, 3ʻhigh, 4ʼ wide, and 7ʼ long, what percent of a cord is that? If a cord of wood sells for $250, how much is that sled load worth?

Electricity Math Volts x Amps = Watts. A light bulb can be 25, 60, 75, 100 Watts or more. If there is 120 Volts in a line. (Like a home wall outlet.) What is the amount of amps used to run the above light bulbs? At $.50/KWH how much does it cost to run each of those light bulbs.

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If there is 12 volts available in a DC electric line. (Like a car battery) How many amps are used to run the above light bulbs at 12 volts?

Writing   Write a clear story or description, at least half a page, about one of the following subjects: •

The most memorable snowmachine, boat or fourwheeler ride. Tell what you think it would have been like before snowmachines, boat motors and fourwheelers.

•

Your family awakes one day with no electricity and fuel. Describe how your family adapts to completing daily chores and routines without these modern conveniences.

•

When you are most hungry, what food you would eat first, and why.

•

How people 50-100 years ago heated their houses, fed their families, and stored their food.

•

If you were involved in an energy career, what career you would pursue?

•

How you think electricity has changed your community in the past 50 years.

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Imagine that you are an electron flowing down a wire at the speed of light. You donʼt know where you are going, or what work you will do next, and you are filled with excitement and apprehension. What is your fate if you are doing your service in a village as opposed to a big city? Will you ever get out of the village?

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How could you get energy without paying for it? Could your whole village make money rather than spending it? How might this happen?

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Discuss “renewable energy.” Where is the energy in your local environment? Can you use it without running out?

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How is energy exchanged in natural living systems? Is it efficient in some or all cases?

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Write about a forest fire close to your village. Was anyone hurt? Did it happen after the young birds were capable of flying away? What did the fire do to transportation in your area? What effect did it have on the country over time? (Blueberries usually spring up after a fire etc.) What energy exchange started the fire? What eventually stopped the fire?

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ASSESSMENT 1) Name the five forms of energy available to us normal folks, and give two examples of each. 2) Four of those forms of energy were part of daily lives for thousands of years. One has only recently become part of daily life. Which one is that? Give three examples of how that form is used in your own life. 3) Of the five forms of energy available to us in daily life, name the form of energy represented with the following: a) wind b) boiling water c) a shock d) a devise to see in the dark e) a peanut butter sandwich 4) Which form of energy is more easily converted to other forms? Give two examples from your own life. 5) Which form stores energy better than the others. Give two examples from your own life. 6) Give two examples of kinetic energy and potential energy from your own life. 7) Heat travels in three possible ways. What are they? 8) Energy is converted from one form to another. Is that process 100% efficient, or is there always a loss? Give an example of an inefficient process. 9) What is your definition of efficiency? 10) Give the energy trail for the following: a) a raven flies over your house (use imagination) b) a radio picks up the KSKO signal. c) OR give two energy trails that start with you and go back to the source of energy. 11) What is the source of almost every energy trail in our lives? 12) A material that allows electricity or heat to pass through easily is call a __________. A material that doesnʼt allow electricity or heat to pass through easily is called an _________. 13) Name the two devises put in electrical circuits to make them safe. For extra credit, tell how each one makes the circuit safe.

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14) There are two kinds of electrical circuits, one cannot be transmitted far in a wire. It is called_________________. The other can be transmitted far in a wire. It is called __ ____________. Give examples of two appliances or tools that operate on each one. 15) A circular saw uses 10 amps. With the current coming from the wall socket, how many watts is that? A 12 volt LED light uses .05 watts. How many amps is that? A coffee pot uses 1000 watts an hour. If electricity is $.55 a kwh, how much does it cost to run that coffee pot for an hour? A day? A month? 16) Identify three possible alternative energy sources available in your community.

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