Transcript energy overview

Catherine Walker
Energy:
What is it?
Forms and States
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 Organisms
Living organisms need energy for growth and
movement.
Your body uses energy
Even if you’re not moving.
Food contains nutrients which
Produce energy and help to
Grow and repair the body.
You use more energy if you’re
Active, and less if you’re resting.
Your body uses energy even
If you’re asleep or resting.
Your body needs enough
food to keep itself at the
right temperature.
Energy is needed to pump
Blood around your 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
transportation
purposes?
Energy Conversion
Energy 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.
Energy Conversion Example
Green plants convert the sun’s energy into chemical
energy through the process of photosynthesis.
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.
KE = mass x velocity2
2
What has a greater affect on
kinetic energy: mass or
velocity? Why?
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 Energy
Water 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
Note: Not meant as a complete list of
energy types.
•
•
•
•
•
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Chemical
Electrical
Light
Mechanical
Thermal (heat)
Nuclear
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 Words
Electrical energy
Energy
Energy conversion
Gravitational potential energy
Joules
Kinetic energy
Law of conservation of energy
Potential energy
Light energy
Mechanical energy
Nuclear energy
Thermal energy
Complete Concept Map
Sources
Images used for educational purposes only.
PowerPoint inspired by:
education.jlab.org/jsat/powerpoint/energy_forms_a
nd_changes.ppt
Slide 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.jpg
Bicycle: http://westernskycommunications.com/images/bicycle-photography-ua-criterium-11-cornering.jpg
Spring: http://crfsonly.com/howto/keihin-fcr-carb/honda-crf-hot-start/how-to-install-zip-ty-hot-start-nut.php
Backpack: 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.jpg
Dam: http://zonalandeducation.com/mstm/physics/mechanics/energy/gravitationalPotentialEnergy/wtrfl1.jpg
Apple: 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