bell ringerthursday feb 6, 2014 what are 3 ways that we could “get” energy to power our school?
TRANSCRIPT
Bell Ringer Thursday 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 #2Lab 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 #2Lab 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 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 (1642-1727)
Did not know about energy
Existence still being debated in 1850
Albert Einstein (1879-1955) In 1905 proposed:
E=mc2
A conserved, substance-like quantity that has the ability to cause change.
Energy
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 Ek?? Velocity
Mass
Energy Stored Kinetically (Ek)
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
Energy Storage Mechanisms
The Energy of Motion.
Factors that can change Ek?? Velocity
Mass
Energy Stored Kinetically (Ek)
Energy Stored Potentially Energy Stored
Gravitationally (Eg)(Stored in the Field)
Factors that can change Eg? Height from reference
point
Mass
Gravitational Field
Force
Energy Stored Elastically (Eel)
Factors that can change Eel? 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 (Echem)
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 (Ediss)
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)
Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss
LOL DiagramsBefore Push Right after Push When it comes to a rest
Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss
Process of Working Working
Process of energy transfer across system boundary via external forces
There can be…1. No working done2. 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
Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss
Energy Storage Mechanisms Energy Stored Kinetically (Ek)
Factors: velocity, mass Energy Stored Gravitationally (Eg)
Factors: height, mass, field strength Energy Stored Elastically (Eel)
Factors: stretch/compress distance, material Energy Stored Chemically (Echem)
Examples: Reactions, Food, Gas Tank, Battery Energy Stored Internally (Ediss)
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.
Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss Ek Eg Eel Echem Ediss