energy: what is it? forms and states
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Energy: What is it? Forms and States. Catherine Walker American Public University. What is Energy?. Energy is defined as the ability to do work. If an object or organism does work, the object or organism uses energy. Energy makes everything happen. Energy is all around you!. - PowerPoint PPT PresentationTRANSCRIPT
Energy: Energy: What is it? What is it?
Forms and StatesForms and States
Catherine WalkerAmerican Public University
What is Energy?
• Energy is defined as the ability to do work.
• If an object or organism does work, the object or organism uses energy.
• Energy makes everything happen.
Energy is all around you!• You can hear energy as sound.• CRASH! BANG! Did you hear that sound? It was
made by air vibrating.
• You can see energy as light.• Items such as light bulbs and television screens
give off this light energy.
• You can feel energy as wind.• Windmills and sailboats are powered by wind
energy.
Living OrganismsLiving organisms need energy for growth and
movement.
Your body uses energyEven if you’re not moving.
Your body needs enoughfood to keep itself at theright temperature.
You use more energy if you’reActive, and less if you’re resting.
Your body uses energy evenIf you’re asleep or resting.
Energy is needed to pumpBlood around your body.
Food contains nutrients whichProduce energy and help to Grow and repair the body.
We are always using energy• You use energy when you:• Hit a baseball• Ride a bike• Compress a spring • Lift your backpack
How have you used energy today?
Energy is used for…
Can you give an example of how
energy is used for residential and commercial, industrial, or
transportationpurposes?
Energy ConversionEnergy cannot be created or destroyed; it can only be changed from one form to another. When energy changes from one form to another the process is called energy conversion.• The sun’s energy through solar cells can be converted
directly into electricity.• In an electric motor, electromagnetic energy is
converted to mechanical energy.• In a battery, chemical energy is converted into
electromagnetic energy.• The mechanical energy of a waterfall is converted to
electrical energy in a generator.
Green plants convert the sun’s energy into chemical energy through the process of photosynthesis.
Energy Conversion Example
States of Energy
• Kinetic Energy is the energy of motion.• Potential Energy is stored energy.
States of Energy
Kinetic Energy• The energy of motion is called kinetic energy.• The faster an object moves, the more kinetic energy it
has.• The greater the mass of a moving object, the more
kinetic energy it has.• Kinetic energy depends on both mass and velocity.
What has a greater affect on kinetic energy: mass or velocity? Why?
KE = mass x velocity2
2
Potential Energy• Potential Energy is stored energy.• Stored chemically in fuel, the nucleus of atom, and
in foods.• Or stored because of the work done on it:• Stretching a rubber band.• Winding a watch.• Pulling back on a bow’s arrow.• Lifting a brick high in the air (known as
Gravitational Potential Energy).
Gravitational Potential EnergyWater behind a dam, a bolder sitting on a hillside, an apple hanging from tree all have gravitational potential energy.
Gravitational Potential Energy
PE = m (mass) x g (gravity) x h (height)
A cinder block that weighs 60 kilograms is sitting on a platform 20 meters high.
How much gravitational potential energy does it the cinder block have?
60 x 9.8 x 20 = 11,760 Joules of gravitational energy potential
Joules – How Energy is Measured• Both kinetic energy and potential energy are
measured in Joules.
• James Prescott Joules (1818-1889) was a British physicist who established the mechanical theory of heat and discovered the first law of thermodynamics.
• Joules don't equal watts—one is a measurement of energy, one is a measurement of power.
• 1 Watt = 1 Joule used per each second.
Common Forms of Energy
• Chemical• Electrical• Light• Mechanical• Thermal (heat)• Nuclear
Note: Not meant as a complete list of energy types.
Online Quiz
Key Concept: Law of Conservation of Energy• The total amount of energy in the universe is constant.• Energy can be neither created nor destroyed.• It can only be converted from one form to another.
Complete Energy Worksheet
Vocabulary WordsElectrical energyEnergyEnergy conversionGravitational potential energyJoulesKinetic energyLaw of conservation of energyPotential energyLight energyMechanical energyNuclear energyThermal energy
Complete Concept Map
SourcesSlide 1: http://www.conserve-energy-future.com/Images/Energy_Sources.jpg
Slide 2: http://www.unleashyourvitality.com/wp-content/uploads/2010/03/energy.jpg
Slide 4: http://www.grainchain.com/images/topics/11-14/energyOut.png
Slide 5: Baseball: http://www3.pictures.gi.zimbio.com/Olympics+Day+10+Baseball+JOgQPeBHoVrl.jpgBicycle: http://westernskycommunications.com/images/bicycle-photography-ua-criterium-11-cornering.jpgSpring: http://crfsonly.com/howto/keihin-fcr-carb/honda-crf-hot-start/how-to-install-zip-ty-hot-start-nut.phpBackpack: http://www.zimbio.com/pictures/retd20EgMW4/Olympics+Day+10+Baseball/JOgQPeBHoVr/Sun+Lingfeng
Slide 6: http://205.254.135.7/energy_in_brief/major_energy_sources_and_users.cfm
Slide 8: http://www.dynamicscience.com.au/tester/solutions/electric/energyconversions.htm
Slide 9: http://www.petervaldivia.com/technology/energy/image/potencial-and-kinetic.bmp
Slide 10: http://www.youtube.com/watch?v=7K4V0NvUxRg&feature=related
Slide 13:Bolder: http://www.bbc.co.uk/schools/ks3bitesize/science/images/boulder.jpgDam: http://zonalandeducation.com/mstm/physics/mechanics/energy/gravitationalPotentialEnergy/wtrfl1.jpgApple: http://gurneys.com/images/250/12958.jpg
Slide 17: http://glencoe.mcgraw-hill.com/sites/dl/free/0078695104/160350/00076705.swf
Slides 5, 6, 11, 14, 18, 20, and 21: http://bicycledriving.org/enforce/traffic/images/knowledgecheck.jpg
Slide 19: http://www.frankswebspace.org.uk/ScienceAndMaths/physics/physicsGCSE/efficiency.htm
Images used for educational purposes only. PowerPoint inspired by: education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt