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Agenda for Wednesday Dec 7 th Energy House of cards Energy notes. Energy. What is energy? How do we use energy? Read page C-3. House of Cards. Agenda for Thursday Dec 8 th Energy notes Drive a nail Lab. Energy Vocab. Potential energy – stored energy, energy of position
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Agenda for Wednesday Dec 7th • Energy • House of cards • Energy notes
Energy What is energy? How do we use energy? Read page C-3
Agenda for Thursday Dec 8th • Energy notes • Drive a nail Lab
Energy Vocab • Potential energy – stored energy, energy of position • Skier at the top of a hill • Gas • Kinetic Energy – energy of motion • Skier moving down the hill • Gas being burned
Nature of Energy • Energy is all around! • Sound • Light • Wind • You use energy when you: • Hit a baseball • Lift your book • Compress a spring
Nature of energy • Living organisms need energy for growth & movement • Energy is involved when • A bird flies • A bomb explodes • Rain falls • Electricity flows through a wire
Nature of energy • 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 to move an object) the object or organism uses energy
Nature of Energy • Direct connection between energy and work • Energy is measured in the same unit as work: Joules (J) • Objects gain energy because work is being done on them
Forms of Energy • 5 main categories • Heat • Chemical • Electromagnetic • Nuclear • Mechanical
Heat Energy • Moving particles produce heat • Heat energy can be produced by friction • Heat energy causes changes in temp. and phase of any form of matter
Chemical Energy • Required to bond atoms together • When bonds are broken, energy is released • Fuel and food are forms of stored chemical energy
Electromagnetic Energy • Power lines carry electromagnetic energy into your home in the form of electricity • Light is a form of electromagnetic energy • Each color (ROY G BIV) is a different amount of electromagnetic energy • X-rays, radio waves, and lasers
Nuclear Energy • Nucleus of an atom is the source of nuclear energy • Fission (nucleus splits) – energy is released as heat and light • Fusion (nuclei joins) – energy is released
Nuclear Energy • Sun’s energy is from a nuclear fusion reaction • Hydrogen nuclei fuse to form helium nuclei • Nuclear energy is the most concentrated form of energy
Mechanical Energy • When work is done to an object, it gains energy • Energy it gains is mechanical energy • When you kick a football, you give mechanical energy to the football to make it move • Give energy to a Bowling ball, ball hits pin and they get energy
Energy Conversion • Energy can be changed from one form to another • Changes in forms of energy are energy conversions • All energy forms can be converted to other forms • Sun through solar cells to electricity • Plants take sun energy to sugars (electromagnetic to chemical)
States of Energy • Most common energy conversion is between potential and kinetic energy • All forms of energy can be in either of 2 states • Potential • Kinetic
Kinetic Energy • Kinetic Energy – energy of motion • Depends on mass and velocity • Faster an object moves, more kinetic energy it has • Greater the mass, more kinetic energy it has • KE – 1/2mv2 • What has a greater affect of kinetic energy, mass or velocity? Why?
Potential Energy • Potential energy – stored energy • Fuel, nucleus, food • 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
Gravitational Potential Energy • Potential energy that is dependent on height • Waterfall • Suspension Bridge • Falling snowflake • GPE = mgh
Gravitational Potential Energy • If you stand on a 3 meter diving board, you have 3 times the GPE than you had on a 1 meter diving board
Kinetic - Potential Energy Conversions • Roller Coaster • Mechanical energy brings them to the top • This gives them great potential energy • Conversion between potential to kinetic energy powers cars through the entire ride • At the point of max PE, the car has minimum KE
Kinetic - Potential Energy Conversions • As a baseball player throws the ball into the air, various energy conversions take place
Law of Conservation of Energy • Energy cannot be created or destroyed • It can only be converted from one form to another • Albert Einstein • mass and energy can be converted into each other • Matter is destroyed, energy is created and vice versa • E = mc2
Agenda for Friday Dec 9th • Finish yesterday’s lab • Energy Conversion in a bouncing ball lab • Video