Transcript Transfer of Energy

Acronym
• Original List
– Moving Large Stuff
• Mechanical
– Grav, elast, sound
– Moving Atomic Stuff
•
•
•
•
•
Heat
Light
Chemical
Electrical
Nuclear
• MECH-’n Legs
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–
–
–
–
–
–
–
–
Mechanical
Electrical
Chemical
Heat
Nuclear
Light
elastic
gravitational
sound
I will wait for the sumo industrial strength walker
Transfer of Energy
The six Primary “forms” of
energy in a nutshell

Mechanical: An object in motion or position.

Gravitational, Elastic, Sound

Heat: Energy via moving / vibrating atomic particles

Electromagnetic: Disturbance of the electromagnetic field
from vibrating charged (+/-) particles

Chemical: Bonds between atoms

Electric: Moving Electrons

Nuclear: Energy stored in the Nucleus of an Atom.
Work = Energy
• Work
– Moving an object by pushing it.
– a transference of energy
• Energy:
– The Ability to do work (move both large or small objects)
– It’s what causes change.
Three main concepts of
transfer:
• There is a total set amount of energy in
the universe.
• All energy is conserved
– it’s neither created or destroyed
– All forms of energy are interchangeable
Remember: Work is a transference of energy
Conservation of Energy
• Energy cannot be created or destroyed
• Energy can only be transferred (Changed from
one form to another)
– Heat energy is usually a bi-product of that transfer
Roller Coaster
The Gravitational Potential
Energy of the roller coaster
transfers Into Kinetic Energy
when it rolls down the hill!
Watch the graphs while
the coaster falls!
Potential
Kinetic
Rocket
Watch the graphs while
the rocket takes off:
Potential
Kinetic
But it isn’t as simple as
that!
There is more energy involved here
than just Potential and Kinetic:
Chemical
Potential
Kinetic
Gravitational
Potential
Heat
All Forms of Energy are Inter-changeable
Chemical
Energy
Nuclear
Energy
Heat
Energy
Electromagnetic
Energy
Electrical Energy
Mechanic
Energy
DVD: Energy (Discovery)
Energy Form Transfer:
• Any Form of energy can change into
pretty much any other form of energy
including a change into more than one at
a time!
Heat
Nuclear
Electromagnetic
Heat
Chemical
Chemical
Mechanical
Heat
Heat
Electric
AllDid
energy
also
make
heat!
Thisenergy”
heat is usually lost to space..
Think:
you changes
notice how
many
times
“heat
showed up? What might explain this?
Conservation of Energy:
The pendulum will NOT gain or lose energy when it swings!
It only swings with as much energy as it is given!
Application of Energy
Conservation:
• But we realize that
pendulums WILL eventually
slow down and stop
swinging! This seems to
contradict the Law of C.E.
Friction from air resistance
Both forces act to slow down and
eventually stop the pendulum.
• BUT IT DOESN’T!
• Can you explain why the
pendulum does slow down?
(hint: think about forces!)
Gravity is constantly pulling down
Transfer of Gravitational
Mechanical Energy
• Pendulum
– Potential & Kinetic energy go back and forth
between each other.
– Energy is conserved in the process.
Greatest Potential Energy
Greatest Kinetic Energy
Transfer of Mechanical Energy
Greatest Potential
Energy
PE=MGH
G=9.8m/s2
Greatest Kinetic
Energy
KE+MV2
3s
3s
2s
4s
1s
5s
0s
6s
Kinetic
Energy
KE=1/2mv2
(work = Force x Distance)
Potential
Energy
PE=mgh
Work = Weight x Height
Converting Gravitational Potential
to Gravitational Kinetic
Where does the energy go
after I drop the ball?
When you drop the ball,
all of the gravitational
potential energy is converted
into gravitational kinetic.
Once it hits the ground, some
of that energy is converted
into elastic, heat & sound.
When it bounces back up, it
regains gravitational potential.
Mass,
Mass,
Gravity
Gravity
& Height
& Height
Collision creates heat!
Demo: Collision Balls – Baseball Discussion
Energy & Friction
• Friction turns mechanical energy into heat
Chemical, Mechanical
& Heat
• All energy can be transferred from one form
to another.
For example:
Chemical  Mechanical Heat
Converting Elastic Potential to Elastic
Kinetic Energy (click to play video)
What kind of energy conversions do
you see here? (Click to play video)
Life Sustaining Energy
• Transforming Nuclear Energy into Energy
We can Use.
– Harvesting and changing energy so we can
use it to our benefit.
It all comes from
somewhere…
We can draw a “flow chart” to
show energy changes:
Gravitational
Potential
Mechanical
Electric
Electromagnetic and Heat
Moving water turns a “generator” to make electricity that comes to
our house and we use for lots of things
The Sun –
The origin of all our Energy!
• The Sun is the source for all of our energy in
our solar system.
• The heat caused by pressure and gravity of the
sun causes all energy – even the nuclear
reactions!
Element Table
of the sun
Conversion 1:
Nuclear  Electromagnetic &
heat energy
Nuclear
Heat
Light (EM)
Conversion 2: Light 
Chemical (Photosynthesis)
Nuclear, Electromagnetic
& Heat
Chemical
(Photosynthesis)
Conversion 3:
Chemical  Chemical (Meat)
Chemical
(Photosynthesis)
Chemical
(Biomass)
Conversion 4: Chemical
(Meat)  Mechanical & Heat
Mechanical
(Movement)
Chemical
Heat
Electrical Energy
Transformations
What forms of energy do you see in this picture? What transformed into what?
Conversion 1-4: Nuclear 
Light  Thermal  GPE
Nuclear Energy 
Electro-magnetic (light)
+ Heat
Thermal Energy to
Gravitational Potential Energy
Conversion 4-7: GPE  GKE
 Mechanical  Electrical
Conversion 6-9: Mechanical 
Electrical  Light & Heat
Mechanical
Electrical
Light & Heat
Class Activity
• Fill in the following transfers:
• Falling Ball
_____  ______  _____ + _____ + _____
Wax to burning a candle
_____  ______ + ______