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