Download Energy - TSDCurriculum

Energy Types
Notes part 1
What is Energy?
• Energy: the ability to make a physical
change or cause a rise in temperature.
Energy Units
1 chocolate chip
has 3000
calories!
Energy in Many Forms
(KE) Kinetic Energy:
Energy of mass in
motion (runner, car)
1
𝐾𝐸 = 𝑚𝑣 2
2
KE = ½ mass times velocity squared
Energy in Many Forms
(GPE) Gravitational Potential Energy:
Energy stored in the distance
between masses
(moon & earth, lifted book)
𝐺𝑃𝐸 = 𝑚𝑔ℎ
GPE = (mass)(9.8)(height above the earth)
Energy in Many Forms
(EE) Elastic Potential Energy:
Energy stored in the stretch and
compression of molecular bonds
(springy, stretchy)
(CE) Chemical Energy:
Energy stored in atomic bonds
(chemical reactions, explosions)
Energy in Many Forms
(TE) Thermal Energy:
Energy of vibrations of atoms and
molecules (determines temperature,
often mistakenly called heat)
Match: Energy name with marker
Energy Type
A. Kinetic energy
B. Gravitational PE
C. Elastic energy
D. Chemical energy
E. Thermal energy
Marker
1. Height & mass
2. Temperature
3. Atomic bonds
4. Stretch
5. Speed & mass
KEY: Energy name with marker
Energy Type
A. Kinetic energy
B. Gravitational PE
C. Elastic energy
D. Chemical energy
E. Thermal energy
Marker
1. Height & mass
2. Temperature
3. Atomic bonds
4. Stretch
5. Speed & mass
Which form(s) of energy?
Which form(s)
of energy?
Which form(s) of energy?
Which form(s) of energy?
Which form(s) of energy?
Which form(s) of energy?
http://commons.wikimedia.org/wiki/File:Turkish_Stars_2217.JPG
End of notes part 1
Notes Part 2: Conversions
Energy Conversion:
Energy transferred (between objects) or
transformed (one type to another), often
by a force applied across a distance.
(GPE gradually
changes to KE as
diver falls)
System:
• All of objects that are of interest.
• Example: Your machine is the system and
the surroundings are not the system.
Energy “losses”:
• Energy is never lost, but it can leave the
system or become less useful.
• Example: KE becomes thermal energy or
sound.
Conservation of Energy:
• A scientific law that the total amount of
energy in the Universe does not change
(except in nuclear processes).
• “Energy is never created or destroyed”,
it just moves in or out of the system, or
transforms into a less useful form.
• Different from recycling, etc.
Energy: Neither created nor destroyed,
just changes form.
Explain energy conservation in this
scene.
Sockeye Salmon
Explain energy conservation in this
scene.
End of notes part 2
Notes 3: Force Causes Energy Change
Notes 3: Force Causes Energy Change
Work: Converts energy (transformations
& transfers). Work is done by applying a
force across a distance.
𝑊 = 𝐹𝑑
Work = Force x distance
Notes 3: Force Causes Energy Change
Force: A push or a pull.
Only 4 forces in nature:
gravity
electromagnetic – push/pull
strong nuclear – bombs
weak nuclear – radioactivity
(The last 2 hold the atom together)
Notes 3: Force Causes Energy Change
Force of gravity (Fg): The force of one
mass on another due to a gravitational field
Gravitational field: Surrounds all masses
and causes the force of gravity (Higgs)
Notes 3: Force Causes Energy Change
• Electromagnetic force (EM Force): The
electric and magnetic force between particles.
Caused by the EM field.
• Electromagnetic field: Surrounds charged
particles and causes the EM force (photons).
End of notes part 3
Energy Conservation - Bar Graphs
E(J)
4
3
2
1
0
E(J)
KE GPE EPE
4
3
2
1
0
KE GPE EPE TE
KEY: KE = kinetic energy, GPE = gravitational potential energy
EPE = elastic potential energy, TE = thermal energy
Complete the Bar Graphs
v=0
E(J)
4
3
2
1
0
Initial
E(J)
4
3
2
1
0
KE GPE EPE
Final
KE GPE EPE TE
How much TE is produced?
KE = ½ mv2 GPE = mgh
Final: speed v = 0 m/s
mass m= 1 kg
height h = 15 m
g = 10 m/s2
GPE = (1)(10)(15) = 150 J
E(J)
200
150
100
50
0
KE GPE EPE TE
E(J)
Initial: speed v = 20 m/s
mass m= 1 kg
height h = 0
KE = ½ (1)(20)2 = 200 J
200
150
100
50
0
KE GPE EPE