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Energy Demonstration Kit and Sample Energy DemonstrationsIncluded in the Energy Demo Kit are:Wind-up toyPill bottle or film canister containing popcorn seeds 9V battery and LED with resistor attached (LED/resistor stored in a prescription pill bottle to keep intact) Rubber Bands (3 of various sizes)Shaker (Faraday) FlashlightRubber Bouncy BallWhatever you would like to add to it! Refer to the Sample Energy Demonstrations packet that follows for ideas on how to use these materials to demonstrate different types of energy. Starred (*) demos have demonstration materials included in the kit. Sample Energy DemonstrationsThis document contains definitions of the different types of energy and examples or sample demonstrations to use in your classes. The definitions were taken from the KEEP Activity Guide. Many of the demonstration materials can be found in theEnergy Demo Kit provided by KEEP. Included are the following:FORMS OF ENERGYKinetic Energy Definition and examples…………………………………………………………3Potential Energy Definition and Examples……………………………………………………..3Chemical Potential Energy Definition and Examples……………………….3Elastic Potential Energy Definition and Examples……………………………3Electrical (Electromagnetic) Potential Energy Definition and Examples………………………………………………………………………………………..4Gravitational Potential Energy Definition and Examples…………………4Nuclear Energy Definition, Examples, and Demos…………………………..5Thermal Energy Definition and Examples……………………………………….5Mechanical Energy Definition, Examples and Demo………………………………………6Sound Energy Definition, Examples, and Demos………………………………………..….6Radiant (Light) Energy Definition and Examples…………………………………………….6ENERGY TRANSFERWork: Definition and Demos……………………………………………………………..………….7Heat Transfer (Heat Energy): Definition and Demos………………………………………7ENERGY CONVERSIONSChemical Potential Energy Conversions: Description and Demos…………………..8Elastic Potential Energy Conversions: Description and Demos……………………….9Electrical (Electromagnetic) Potential Energy Conversions: Description and Demos……………………………………………………………………………………………………….….10Gravitational Potential to Kinetic Energy: Description and Demo………………….11FORMS OF ENERGYAll objects and systems have a number of forms of energy within them. The two main forms of energy are kinetic energy and potential energy. Two other common forms of energy, mechanical energy and sound energy, are a combination of kinetic and potential energy. Radiant (light) energy is regarded by some scientists as a form of energy, although most treat it as a means of energy transfer. KINETIC ENERGYDEFINITION: Kinetic energy (KE) is the energy possessed by a moving object or system of objects. The equation for kinetic energy is ? x (mass) x (velocity squared), or KE = (1/2)mv2. EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE KINETIC ENERGY: A thrown football, a speeding automobile, a rock falling from a cliff, and the flying fragments of a firecracker right after it has exploded.POTENTIAL ENERGYDEFINITION: Potential energy (PE) is the energy stored in an object or system because of its position or the arrangement of its parts. Forms of potential energy include chemical, elastic, electrical (electromagnetic), gravitational, nuclear, and thermal energy. EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE POTENTIAL ENERGY: wood (chemical PE), a stretched rubber band (elastic PE), a battery (electrical PE), a rubber ball sitting on a table with respect to the floor (gravitational PE), the nucleus of an atom (nuclear energy), a hot cup of coffee (thermal energy).CHEMICAL POTENTIAL ENERGYDEFINITION: Chemical potential energy is the energy stored in the chemical bonds that hold the atom of a molecule together. When a chemical reaction occurs, the bonds that hold molecules together are broken and rearranged, and energy is released. EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE CHEMICAL POTENTIAL ENERGY: Food, wood, fossil fuels. A charged battery has chemical potential energy stored in it. The battery also has electrical potential energy. These forms of potential energy work together to create an electrochemical reaction that produces an electric current when the battery is connected to a circuit (see Electrical (Electromagnetic) Potential Energy).ELASTIC POTENTIAL ENERGYDEFINITION: Elastic potential energy is the energy stored in an object or system when it is stretched or compressed from its relaxed position. It occurs when an object (skin or rubber band) resists being stretched out of shape.EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE ELASTIC POTENTIAL ENERGY: A stretched rubber band, a stretched or compressed spring, and the compressed air in a bicycle pump. The elastic potential energy in a rubber band can be used to do work (toy airplanes fly when a rubber band untwists and spins a propeller. The elastic potential energy in the rubber band was converted to kinetic energy.ELECTRICAL (ELECTROMAGNETIC) POTENTIAL ENERGYDEFINTION: Electrical energy is potential energy stored by separating positive and negative electrical charges against electrical forces. In nearly all cases, it is negative charges in the form of electrons that are separated from atoms. When separated, the negative charges (electrons) are attracted to the atoms they were removed from because these atoms now have a net positive charge. Hence, the electrons have electrical potential energy with respect to the atoms they were removed from. Like charges also have electrical potential energy with respect to each other since they exert repulsive forces on each other (negative charges repel other negative charges, positive charges repel other positive charges)In certain metals such as iron and nickel, the electrons orbiting their atomic nuclei may be arranged in such a way as to create magnetic fields, causing these metals to act as magnets. Electrons moving as an electric current also create magnetic fields. The poles of two separate magnetic fields have potential energy with respect to each other. The magnetic poles will exert forces on each other that are either attractive (North and South poles) or repulsive (North and North poles, South and South poles). Due to the role played by moving electric charges in creating magnetic fields, this form of potential energy is referred to as electromagnetic potential energy. EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE ELECTRICAL (ELECTROMAGNETIC) POTENTIAL ENERGY: A balloon after it has been rubbed on someone’s hair. The balloon has excess negative charges (electrons) on it, while the hair has a net positive charge on it. During thunderstorms, clouds have electrical potential energy with respect to the ground. A charged battery has electrical potential energy stored in it. The battery also has chemical potential energy. These forms of potential energy work together to create an electrochemical reaction that produces an electric current when the battery is connected to a circuit (see Chemical Potential Energy). The poles of two bar magnets brought close to each other have electromagnetic potential energy with respect to one another. GRAVITATIONAL POTENTIAL ENERGYDEFINITION: Gravitational potential energy is a form of potential energy stored in objects by separating them from other objects against the force of gravity. The gravitational potential energy of an object is equal to its weight (mass x acceleration due to gravity) times the height to which the object is lifted. The equation for gravitational potential energy (GPE) is (mass) x (acceleration due to gravity) x (height), or GPE = mgh.EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE GRAVITATIONAL POTENTIAL ENERGY: A rubber ball on a table will have gravitational potential energy with respect to the floor. A rubber ball placed at the top of a staircase will have gravitational potential energy with respect to the bottom of the staircase. A rock sitting on top of a cliff has gravitational potential energy with respect to the ground. NUCLEAR ENERGYDEFINITION: Nuclear energy is a form of potential energy stored in the nuclei of atoms. It is released by fission (the splitting of the nuclei of heavy atoms such as uranium) or by fusion (the combining of the nuclei of light atoms such as hydrogen). Aside from these nuclear processes, it is very difficult to release nuclear energy from most atomic nuclei.EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE NUCLEAR ENERGY: Nuclei of certain isotopes of heavy elements such as uranium, plutonium, and thorium release nuclear energy via fission. Examples of this process take place in nuclear power plants and nuclear weapons. Nuclei of light atoms such as hydrogen release nuclear energy when combined via fusion to form helium. Examples of this process take place in the sun and other stars and in some nuclear weapons. DEMOS OF NUCLEAR FISSION AND FUSION: Although a direct demonstration of nuclear fission is not feasible, a nuclear fission chain reaction can be simulated using dominoes. Arrange the dominoes in rows that are close together such that the first row has one domino, the second row has two dominoes, the third row has four dominoes, and so on. Each falling domino represents a Uranium-235 nucleus splitting and releasing two neutrons that split two more U-235 nuclei (cause two more dominoes to fall). For another demonstration of nuclear fission, go to the University of Colorado Physics Education Technology (PhET) web site, which features an interactive computer simulation of fission, at a demonstration of nuclear fusion, look no further than the sun (but don’t look directly at it either). The sun is a giant nuclear fusion reactor that combines or “fuses” hydrogen under tremendous pressures and temperatures into helium to power our solar system and provide Earth’s energy. THERMAL ENERGYDEFINITION: Thermal energy is the total internal kinetic and potential energy of an object due to the random motion of its atoms and molecules. An object that feels hot has more thermal energy inside it than an object that feels cool. Scientists make a distinction between thermal energy and heat, where thermal energy refers to the internal energy of an object and heat refers to the transfer of energy from an object to other objects or to its surroundings. Although technically incorrect, many people use the word “heat” to mean thermal energy (See Heat Transfer).We often think that only things that are hot or have high temperatures have thermal energy. However, anything that has a temperature above absolute zero (–273.15 °C or –459.67 °F) has thermal energy. This is because absolute zero is the temperature where there is virtually no random motion of an object’s atoms and molecules, which also means that the object cannot transfer any energy from itself to its surroundings. EXAMPLE OF OBJECTS AND SYSTEMS THAT HAVE THERMAL ENERGY: A cup of hot coffee or tea has thermal energy, which we can easily detect by carefully touching the cup. A cup of cold water also has thermal energy – it just happens to have less thermal energy than the cup of hot coffee or tea does.MECHANICAL ENERGYDEFINITION: Mechanical energy is a combination of gravitational and/or elastic potential energy and kinetic energy. These forms of energy are usually found in mechanical objects and systems and are continually being converted from one to another. EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE MECHANICAL ENERGY: A block attached to a spring that is moving up and down has mechanical energy. A pendulum has mechanical energy; it continually converts kinetic energy into gravitational potential energy and back into kinetic energy as it swings back and forth. A child also has mechanical energy when he moves about. When sitting, the child has chemical potential energy; but watch out, before you know it, the child will suddenly start running and jumping, converting their chemical potential energy into mechanical energy!*DEMO OF MECHANICAL ENERGY: Wind the wind-up toy and watch it move. The wind-up toy’s gears and springs convert gravitational and elastic potential energy into kinetic energy, while at the same time, the toy itself has kinetic energy as it moves forward. Together, these forms of energy combine to give the moving wind-up toy mechanical energy. SOUND ENERGYDEFINITION: Sound is made up of mechanical vibrations transmitted as waves through a solid, liquid, or gas. Atoms and molecules near a sound source convert elastic potential energy to kinetic energy and back, creating mechanical vibrations that move through the surrounding material medium. EXAMPLES OF OBJECTS AND SYSTEMS THAT HAVE SOUND ENERGY: The sounds that can be detected by the human ear include thunder, speech, music, the sounds made by things colliding or falling, the sounds made by animals, and the sounds made by the wind. Some sounds are beyond the range of hearing. An example is ultrasound, which is used to create images of objects and structures inside the human body.*DEMOS OF SOUND ENERGY: Shake the pill bottle or film canister containing the popcorn seeds and listen to the sound it makes. Gently put your hand on a stereo speaker and listen to the sound from the speaker, while at the same time feel the vibrations the speaker makes. Listen for sounds around you and try to identify their sources.RADIANT (LIGHT) ENERGYDEFINITON: Radiant (light) energy is radiation composed of different wavelengths and frequencies of electromagnetic waves that are produced by various processes ranging from heating, bioluminescence, and other chemical reactions, to radioactive decay and nuclear fusion. Radiant energy is technically a means of energy transfer from an object or system to other objects or its surroundings (see Heat Transfer). However, some scientists treat radiant energy as a form of energy. By itself, radiant energy has no mass so it has neither kinetic nor potential energy. EXAMPLES OF RADIANT (LIGHT) ENERGY: All forms of radiant energy are part of the electromagnetic spectrum, which include radio waves, microwaves, infrared rays, visible light, ultraviolet rays, x-rays, and gamma rays. Radiant energy in the form of visible light is composed of colors ranging from red to violet. White light results when all the colors of the visible light spectrum are combined. Examples of light energy include sunlight, lasers, and light from a fire, a candle, a compact fluorescent light bulb (CFL), an incandescent light bulb, and a light emitting diode (LED).ENERGY TRANSFEREnergy must be transferred from one object or system to another in order for something to happen. Energy can be transferred in two ways: by doing work or by transferring heat. When energy is transferred to an object or system, it is often converted within that object or system into other forms of energy. WORKDEFINITION: The transfer of energy from one object or system to another by applying a force over a distance. The formula for work is (force) x (distance), or Work = Fd.DEMOS OF WORK: Push a toy car that is initially at rest on the floor and then let it go. The moving car now has kinetic energy after you let go of it. To move the toy car, you had to transfer energy from your body to the toy car by exerting a force on the car over a distance. Another way to demonstrate work is to lift an object against gravity. Pick up the rubber bouncy ball from the floor and place it on a table. The ball on the table now has gravitational potential energy with respect to the floor. To raise the ball from the floor to the table, you had to transfer energy from your body to the ball by exerting an upward force on the ball through a height (a vertical distance).HEAT TRANSFER (HEAT ENERGY)DEFINTION: Heat is the transfer of energy from one object at a higher temperature to another object at a lower temperature. Although technically incorrect, the term “heat energy” or “heat” is often used to mean “thermal energy” (see Thermal Energy). Heat can be transferred by conduction, convection, or radiation. Conduction is heat transfer from particle to particle by direct contact, occurring most effectively in solids. Convection is heat transfer by the movement of liquids and gases. Radiation is heat transfer via electromagnetic waves and is sometimes referred to as radiant energy. Although radiant energy is technically a means of energy transfer, some scientists treat radiant energy as a form of energy (see Radiant (Light) Energy).Note that the term “radiation” is also used in science to refer to nuclear radiation, which is the emission of particles and electromagnetic waves from nuclei that undergo radioactive decay, fission, or fusion. Nuclear radiation is not considered to be an example of heat transfer, although there may be some heat transfer associated with nuclear radiation.DEMOS OF HEAT TRANSFER: Turn on a hair dryer (you’ll need to provide your own) and let it run for a few seconds. Carefully touch the hair dryer to experience the heat transferred from the hair dryer to your finger by conduction. Feel the warm air coming out of the hair dryer with your hand. The moving warm air transfers heat from the hair dryer to your hand by convection. The warm hair dryer also transfers heat by radiation of infrared rays, although our senses cannot detect these rays directly.ENERGY CONVERSIONSWhile objects and systems possess different forms of energy, the changes in the world that we see are due to objects or systems converting one or more forms of energy into other forms. CHEMICAL POTENTIAL ENERGY CONVERSIONSDESCRIPTION: When substances undergo chemical reactions, their chemical potential energy can be converted into other forms of energy. In nearly all chemical reactions, some of the chemical potential energy is converted into kinetic, radiant (light), mechanical, and/or sound energy while the rest is converted into thermal energy. Therefore, more than one form of energy is usually present after a chemical potential energy conversion. DEMOS OF CHEMICAL POTENTIAL ENERGY CONVERSIONS:CHEMICAL POTENTIAL TO KINETIC ENERGYLight a small firecracker outdoors and watch the pieces of the firecracker scatter in all directions. Some of the chemical potential energy in the original firecracker is converted into the kinetic energy of the flying firecracker fragments.CHEMICAL POTENTIAL TO RADIANT (LIGHT) ENERGYStrike a match and watch it light up. The combustion of the wood with oxygen and the phosphorous on the tip of the match react to produce visible light. Watch the flames from wood being burned in a fireplace, the tip of a candle burning, or the natural gas burning in a stove burner. Also watch the dazzling light from fireworks or the sparks shooting out from lit sparklers. All of the light you see from these are the result of some of the chemical potential energy in these substances being converted into radiant (light) energy. CHEMICAL POTENTIAL TO THERMAL ENERGYLight a match or burn a thin wooden splint. Carefully, place your hand near the flame (Caution: be sure not to place your hand too close to the flame so that you don’t get burned!). Heat is transferred from the flame to your hand, which increases the thermal energy of your hand. Hence your hand feels warmer. This results when chemical potential energy stored in the wood reacts with oxygen (and the phosphorous tip of the match) and is converted into thermal energy. Another demonstration of a chemical potential to thermal energy conversion occurs when manganese dioxide is added to hydrogen peroxide. The hydrogen peroxide decomposes into water and oxygen gas, releasing thermal energy in the process. The manganese dioxide is a catalyst, which speeds up the decomposition of the hydrogen peroxide but is not consumed in the reaction. The reaction is shown below: 2H2O2 (liquid) 2H2O (liquid) + O2 (gas) + Thermal Energy [MnO2 catalyst]This demonstration is most effective when 30% hydrogen peroxide is used; the 3% hydrogen peroxide found at the pharmacy will barely produce a noticeable increase in temperature. However, caution should be used as the reaction with 30% hydrogen peroxide will heat up significantly. In addition to the chemicals, a Pyrex beaker or Erlenmeyer flask, goggles, and hot gloves are needed for this demonstration, all of which can be obtained from a school science lab. Most chemical reactions release thermal energy, but in a few cases, chemical reactions can absorb thermal energy. One example is the chemical reaction that takes place when first aid cold packs are put to use to treat injuries. Crush a first aid cold pack and feel it become cold. The chemicals inside react to absorb thermal energy and together become cold as a result. CHEMICAL POTENTIAL TO MECHANICAL ENERGYGet up out of your seat and move around. Swing your arms. Talk to the person next to you. All these actions are the result of some of the chemical potential energy in the food you ate being converted by your body into mechanical energy.Start up an automobile engine and drive it down the road. An automobile engine converts some of the chemical potential energy in gasoline into mechanical energy, thereby moving the automobile as a result. Watch a propeller-driven airplane take off from a runway. The engine of a propeller-driven airplane converts some of the chemical potential energy in aviation fuel (which is similar to gasoline) into the mechanical energy of the engine and propellers, thereby moving the airplane forward through the air. In these examples, only some of the chemical potential energy is converted into mechanical energy, the rest is converted into thermal energy. That’s why automobile and airplane engines get hot after they have been running for a period of time, and why even our bodies feel warmer after moving around.CHEMICAL POTENTIAL TO SOUND ENERGYListen to a firecracker explode. Some of the chemical potential energy in the original firecracker is converted into sound energy, which is perceived as a sudden and loud sound!*CHEMICAL POTENTIAL ENERGY CONVERSIONS IN BATTERIESConnect the 9-volt battery to the light emitting diode (LED) and resistor by placing the resistor lead on the negative terminal of the battery and the LED lead on the positive terminal. See the LED light up. The chemical potential energy and the electrical potential energy stored in the battery work together to create an electrochemical reaction that produces an electric current which lights the LED when the circuit is connected (for more details about the energy conversions in batteries and electric circuits, see Electrical (Electromagnetic) Potential Energy Conversions).ELASTIC POTENTIAL ENERGY CONVERSIONSDESCRIPTION: The elastic potential energy in objects like rubber bands and springs can be converted into other forms of energy such as kinetic and thermal energy by stretching and contracting them. DEMOS OF ELASTIC POTENTIAL ENERGY CONVERSIONS: *ELASTIC POTENTIAL TO KINETIC ENERGYPlace one end of a rubber band on your index finger, stretch it and then release it and watch it fly across the room (Caution: be sure that you do not aim the rubber band at anyone). Stretching the rubber band gives it elastic potential energy. Releasing the rubber band converts the elastic potential energy into kinetic energy. *ELASTIC POTENTIAL TO THERMAL ENERGY Stretch a rubber band back and forth quickly, then place it across your cheek. The rubber band feels warm to the touch. Stretching the rubber band back and forth converts elastic potential energy into thermal energy. ELECTRICAL (ELECTROMAGENTIC) POTENTIAL ENERGY CONVERSIONSDESCRIPTION: The electrical potential energy in devices like batteries can be converted into other forms of energy when devices such as light emitting diodes (LEDs) and light bulbs are connected to them in electric circuits. Electromagnetic devices like motors and the Faraday (shake) flashlight convert electromagnetic potential energy into other forms of energy when they are connected in an electric circuit to other devices.DEMOS OF ELECTRICAL (ELECTROMAGNETIC) ENERGY CONVERSIONS:*ELECTRICAL AND CHEMICAL TO RADIANT (LIGHT) ENERGYConnect the 9-volt battery to the light emitting diode (LED) and resistor by placing the resistor lead on the negative terminal of the battery and the LED lead on the positive terminal. See the LED light up. The chemical potential energy and the electrical potential energy stored in the battery work together as an electrochemical reaction to produce an electric current when the circuit is connected (see Chemical Potential Energy Conversions in Batteries). The electric current flowing through the circuit has electrical potential energy. An electrical device connected to a circuit will convert the electrical potential energy in the electric current into other forms of energy. In this demo, the LED is a device that converts some of the electrical potential energy in the current into radiant (light) energy, with the rest of the energy being converted into tiny amounts of thermal energy. The resistor in the circuit acts to provide the proper amount of current for the LED, and in doing so, converts electrical potential energy into tiny amounts of thermal energy. *ELECTROMAGNETIC TO RADIANT (LIGHT) ENERGYShake the Faraday (Shake) flashlight for 30 to 60 seconds to produce and store electrical energy. Now turn the flashlight on and use it like a typical flashlight until its light grows dim. Shake again to recharge the flashlight.A Faraday (Shake) flashlight uses a moving magnet and a capacitor to produce and store electrical (electromagnetic) energy, then uses the stored electrical energy to light the flashlight. Shaking the flashlight moves the magnet through a coil of wires. In doing so, the moving magnetic field causes electric current to flow through the coil of wires. This process is called electromagnetic induction. The electric current from the coils is then transferred to a capacitor, a device that stores electrical potential energy in the form of separated positive and negative electric charges. When the flashlight is turned on, the capacitor in the circuit transfers electrical potential energy to the light bulb, which converts some of this energy into radiant (light) energy, with the rest of the energy being converted into very small amounts of thermal energy. Additional background information describing how the Faraday (Shake) flashlight works can be found at the Shake Flashlights website titled “Shake Flashlights Info” at POTENTIAL TO KINETIC ENERGYDESCRIPTION: The gravitational potential energy of objects can be converted into kinetic energy simply by having them fall toward the ground. *DEMO OF GRAVITATIONAL POTENTIAL TO KINETIC ENERGY CONVERSION: Hold the rubber bouncy ball in your hand while standing. The ball has gravitational potential energy with respect to the floor. Now let the ball drop to the floor. When the ball is dropped, it begins to fall. In doing so, its gravitational potential energy is converted into kinetic energy. On its way down toward the floor, the ball has both gravitational potential energy and kinetic energy, with the combinations of these being equal to the original gravitational potential energy the ball had before it was dropped. The farther the ball falls, the more kinetic energy and the less gravitational potential energy it has. Just before it hits the ground, the ball’s gravitational potential energy will be completely converted to kinetic energy. This complete conversion can be expressed by the equation gravitational potential energy (GPE) equals kinetic energy (KE), or mgh = (1/2)mv2.The conversion of the rubber bouncy ball’s gravitational potential energy into kinetic energy assumes that air resistance acting on the falling ball can be neglected. Air resistance, which is similar to friction, actually converts a small amount of the falling ball’s gravitational potential energy into thermal energy. Additional background information and activities describing the energy of a bouncing ball can be found at the University of Virginia website titled “The Energy of a Bouncing Ball” at ................
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