Bell RingerThursday Feb 6, 2014  What are 3 ways that we could “get” energy to power our school?

Bell Ringer Friday Feb 7, 2014  Label on the diagram:  KE = Max  KE = Min  Write a brief conclusion about KE Lab Group #1Lab Group #2 Lab Group #3 Lab Group #6 Lab Group #5 Lab Group #4  Label on the diagram:  KE = Max  KE = Min  Write a brief conclusion about KE  Label on the diagram:  PE = Max  PE = Min  Write a brief conclusion about PE  Label on the diagram:  PE = Max  PE = Min  Write a brief conclusion about PE  What did you notice about the Total Energy bar as the skater moved?  Draw the bar graph for the skater: At the top, half way down, at the bottom.  What did you notice about the Total Energy bar of the skater on different planets?  Write a brief conclusion about Total Energy.

Bell Ringer Friday Feb 7, 2014  Label on the diagram:  KE = Max  KE = Min  Write a brief conclusion about KE Lab Group #1Lab Group #2 Lab Group #3 Lab Group #6Lab Group #5 Lab Group #4  Label on the diagram:  KE = Max  KE = Min  Write a brief conclusion about KE  Label on the diagram:  PE = Max  PE = Min  Write a brief conclusion about PE  Label on the diagram:  PE = Max  PE = Min  Write a brief conclusion about PE  What did you notice about the Total Energy bar as the skater moved?  Draw the bar graph for skater: At the top, half way down, at bottom.  What did you notice about the Total Energy bar of the skater on different planets?  Write a brief conclusion about Total Energy. Lab Group #7  Where did you notice Thermal Energy?  Write a brief conclusion about Thermal Energy.

What is Energy????

Famous Scientists and Energy  Isaac Newton ( )  Did not know about energy  Existence still being debated in 1850  Albert Einstein ( )  In 1905 proposed: E=mc 2

A conserved, substance-like quantity that has the ability to cause change. Energy

 It has a unit  We can measure it  Has a Value  Not something you can hold  Ability to cause change in another object  Could change the behavior of another object  EX: Ball Substance-Like Quantity Can Cause a Change  Does not change  Cannot be used up  Is Transferred  Ex:  Water  Money Conserved

Our focus in this unit…. How energy is stored. & How energy is transferred.  We will ask ourselves: 1. Where does the energy come from? (Where is it stored?) 2. Where does the energy go? 3. What does the energy do?

1.What conclusions can we draw about KE? Lets look at Kinetic Energy….. 2.What is different about the skater at the top vs. the bottom of the ramp?

Energy Storage Mechanisms  The Energy of Motion.  Factors that can change E k ??  Velocity  Mass Energy Stored Kinetically (E k )

1.What might be changing so the skater’s PE changes from a high PE, lower PE, then zero? 2.It seems to “switch places with KE,” does that mean it has to be stopped or moving slow? Lets look at Potential Energy…..

Not related to motion. Objects have the potential to cause a change as a result of being removed from “where it wants to be.” Example: Bowling Ball Energy Stored Potentially Energy Storage Mechanisms

 The Energy of Motion.  Factors that can change E k ??  Velocity  Mass Energy Stored Kinetically (E k ) Energy Stored Potentially  Energy Stored Gravitationally (Eg) (Stored in the Field)  Factors that can change E g ?  Height from reference point  Mass  Gravitational Field Force  Energy Stored Elastically (E el )  Factors that can change E el ?  Stretch/Compression  Thickness

Battery Gas Tank Food Chemical Reaction What ways can you detect a change as a result of a chemical reaction? Energy Stored Chemically (E chem )

Energy Stored Internally  Scenario: A block moves along the surface of a table.  Question: Is there a change in the system? Energy is no longer “usable” or easily measurable, or recoverable but….. Energy is still there!!! Dissipated Energy (E diss )  Block moves, but where does that energy go once the block comes to a stop?  Heat due to friction  Energy Stored Thermally, sound, etc…

Conservation of Energy Total Energy  What did you notice about the total energy bar graph?  Total amount of energy remains constant  2 Parts  Cannot create or destroy Energy  Transfers Skate Park

Energy Flow diagram (a.k.a LOL Diagrams)  A spring-launched toy which is propelled into the air (Ignore Air Resistance) E k E g E el E chem E diss

LOL Diagrams Before PushRight after PushWhen it comes to a rest E k E g E el E chem E diss

Process of Working  Working  Process of energy transfer across system boundary via external forces  There can be… 1. No working done 2. Positive Working done Energy transfer into system by external forces 3. Negative Working done Energy transfer out of system by external forces

Skater moving down the frictionless ramp. A B C E k E g E el E chem E diss

Energy Storage Mechanisms  Energy Stored Kinetically (E k )  Factors: velocity, mass  Energy Stored Gravitationally (E g )  Factors: height, mass, field strength  Energy Stored Elastically (E el )  Factors: stretch/compress distance, material  Energy Stored Chemically (E chem )  Examples: Reactions, Food, Gas Tank, Battery  Energy Stored Internally (E diss )  Factors: Friction, thermal, sound, etc…

Bell Ringer Feb 10, 2014  A moving cart slows slightly as it rolls towards a spring, and then comes to a stop by compressing the spring. E k E g E el E chem E diss