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Energy is all around you! You can hear energy as sound. You can see energy as light. And you can feel it as wind.

You use energy when you: Hit a softball.

if b k bift your book bag. Compress a spring. Living organisms need energy for growth & movement.

Energy is involved when:A bird fliesbird flies.

A bomb explodes. Rain falls from the sky. Electricity flows in a wire.What is energy that it can be involved in so many different activities?

Energy can be defined as the ability to do work. If an object or organism does work (exerts a force over a distance tomove an object) object or organism uses energy.

Because of direct connection between energy & work, energy is measuredin same unit as work: joules (J).(J)In addition to using energy to do work, objects gain energy as work is beingdone on them.

Five main forms of energy are:1) Heat) Heat2) Chemical3) Electromagnetic4) Nuclear5) Mechanical

) Heat Energy Atoms internal motion is called heat energy, as moving particles produce h

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em ca nergy s requ re o on a oms oge er w en on s arebroken, energy is released.-This is our concern in CHEMISTRY!Fuel & food are forms of stored chemical energyEl t ti EPower lines carry electromagnetic energy into our homeinform of electricity.Light is a form of electromagnetic energy.Eachcoloroflight(RoyGBv)represents different amountof electromagnetic energyElectromagnetic Energy is also carried by X-rays, radio waves, & laser lightlectromagnetic Energy is also carried by X rays, radio waves, & laser light.Nucleus of an atom is source of nuclear energy.Whennucleussplits (fission), nuclearenergyisreleasedinformofheat& light energy.Nuclearenergyisalsoreleased when nuclei collide at high speeds & join (fusion)y g p jThe suns energy is produced from a nuclear fusion reaction in whichhydrogen nuclei fuse to form helium nuclei.Nuclear energy is the most concentrated form of energy.Wh k i d t bj t it i & thi i khen work is done to an object, it acquires energy & this energy is knownas mechanical energy.When we kick a football, we put mechanical energy to footballtomakeitmove.When we throw a bowling ball, we give it energy & when it hits pins, someof energy is transferred to pins (transfer of momentum).Energy can be changed from one form to another. Changes in form ofenergy are called energy conversions.All forms of energy can be converted into other forms.The suns energy through solarcellscanbe converted directly into electricity.Green plants convert the suns energy (electromagnetic) into starches andsugars (chemical energy).In an electric motor, electromagnetic energy is convertedtomechanicalenergy.Chemical energy is converted into electromagnetic energy in a batteryhemical energy is converted into electromagnetic energy in a battery.Mechanical energy of a waterfall is convertedtoelectricalenergy in a generator.In an automobile engine, fuel is burned to convert chemical energy into

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The most common energy conversion is conversion between potential &kinetic energy.All forms of energy can be in either of two states:ya) Kinetic Energy-Is energy of motion.b) Potential Energy-Is stored energy.

The energy of motion is called kinetic energy.Th f bj h ki i i hhe faster an object moves, the more kinetic energy it has.

The greater mass of a moving object, the more kinetic energy it has. Kinetic energy depends on both mass & velocity. K.E. = mass x velocity2Potential Energy

Potential Energy is stored energy.te t a E e gy s sto ed e e gy. Stored chemically in fuel, neucleus of atom, & in foods. Or stored because of work done on it:

Stretching a rubber band.Winding a watch.Pulling back on a bows arrow.Lifting a brick high in the air.

Potential energy, dependingonheight is called gravitational potential energyA waterfall a suspension bridge & a falling snowflake all havewaterfall, a suspension bridge, & a falling snowflake all havegravitational potential energy.If you stand on a 3-meter diving board, you have 3 times the G.P.E, thanyou had on a 1-meter diving board.The bigger they are the harder they fall is not just a saying. Its trueObj i h h G P Ebjects with more mass have greater G.P.E.The formula to find G.P.E. is G.P.E. = Weight X Height.Kinetic vs. Potentia

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place.

Ball slows down Ball speeds up

Energy can be neither created nor destroyed by ordinary means. It can only be converted from one form to another. If energy seems to disappear, then scientists look for itleading to many important discoveries.

In 1905, Albert Einstein said that mass & energy can be convertedinto each other.He showed that if matter is destroyed, energy is created, & ifenergy is destroyed mass is created. E = mc2

EnergyMechanical energy Nuclear energyKinetic energyechanical energy Heat energy Chemical energy Electromagnetic energy

Kinetic energy Potential energy Gravitational potential energy Energy conversion Law of conservation of energy