Transcript Energy - Broken Arrow Public Schools

How could you prove something is
matter?
 How could we test something like air to
prove it is or is not matter?

As a group…
Energy

Is the ability to cause change.
◦ A.k.a. the ability to do work.

There are two general types of energy
known as
◦ Kinetic
◦ Potential
What is Energy?
Energy
Energy exists in many forms.
 Energy can be moved from one
object to another.
 Energy can be changed from
one form to another.
 Energy cannot be created or
destroyed.

Potential Energy
The energy in matter due to its position or
the arrangement of its parts
Kinetic Energy
Energy of a moving object, causing change
http://www.youtube.com/watch?v=Ehx1P
4adv6I
 http://www.youtube.com/watch?v=qZ4FF
WvZtyo
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Video
Forms of Energy
Six Forms of Energy
Mechanical
Heat/Thermal
Chemical
Nuclear
Electromagnetic
Sound
Mechanical Energy
Energy that moves
objects from place to
place
 You use mechanical
energy when you kick a
ball or turn the pedals
of a bicycle
 Other examples include
water flowing in a
stream, tires rolling
down a road and sound
waves from your iPod.

Chemical Energy
Energy released by a
chemical reaction
 The food you eat
contains chemical
energy that is released
when you digest your
meal
 Wood, coal, gasoline,
and natural gas are
fuels that contain
chemical energy

Electrical Energy
Energy that comes from
the electrons within atoms
 It can be generated at a
power plant or inside a
battery and can power
everything from remotecontrolled cars to
refrigerators
 Lightning and static
electricity are also forms
of electrical energy

Heat (Thermal) Energy
Energy created by
the motion of
atoms and
molecules that
occurs within an
object
 Thermal energy
exists when you
heat a pot of water
on a stove

Nuclear Energy
Energy contained in the
nucleus of an atom
 Nuclear energy is released
when nuclei are split apart
into several pieces, or
when they are combined to
form a single, larger
nucleus

Sound
Results from the
vibration or particles in
solids, liquids, and
gasses.
 We are able to detect
these tiny vibrations
with structures in their
ears that vibrate due to
sounds.

Law of Conservation of Energy
With every transformation, some energy is
converted to less useful forms. Energy
conversions are not 100% efficient. The
energy output for the intended purpose is
seldom the same as the energy we put in.
100 J electricity in
95 J heat out
5 J light out!!!!

Montage
◦ Science of Disney Imagineering, The: Energy
Video
Energy Conversion
and Efficiency
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What is an energy conversion?
How efficient are we?
How do power plants work?
How does a Hydroelectric dam work?
How does nuclear energy work? How do
we split an atom?
How does a nuclear power plant work?
What are we taking about?
Energy conversion is where we take one
type of energy and change it to another
type, like from mechanical to
electromagnetic.
 In the process we get some energy that
we intend. However some energy is lost
to other sources.

What is an energy conversion?


We wake up and begin by eating breakfast.
Electromagnetic to Thermal

Chemical to Mechanical

Electromagnetic to Sound
◦ In order to cook food we turn on an electronic stove
which produces heat.
◦ We eat food, which has chemicals and our body converts
the chemical into forms we can use and when we move
we create mechanical energy.
◦ We walk out the door and put in your head phones, this
takes electrical energy from your phone and produces
sound.
These are just a few conversions that occur before
we walk out the door.
Everyday Energy Conversions

Electromagnetic to Thermal
◦ When we were heating our food, the burner glowed this
produced light in addition to heat.

Chemical to Mechanical
◦ When we ate the food, we didn’t use all of the energy
that was there and it becomes our waste products.

Electromagnetic to Sound
◦ While you used your phone it listen to music your phone
also heated up, losing some of the stored energy.

Efficiency is a measure of how much energy that
is put in turns out to be what we want it to be. In
other words, how well do we use our energy.
Unintended energy “loss”
Vehicle Efficiency –
Gasoline Engine
25% Of the gasoline is used to propel a car, the rest is
“lost” as heat. i.e an efficiency of 0.25
Efficiency of Some
Common Devices
Device
Electric Motor
Home Oil Furnace
Home Coal Furnace
Steam Boiler (power
plant)
Power Plant (thermal)
Automobile Engine
Light Bulb-Fluorescent
Light Bulb -Incandescent
Efficiency
90
65
55
89
36
25
20
5
Humans have an efficiency of anywhere
from 20-30%. That means only 20-30%
of what we eat is converted into
movement.
 Remember unlike a car or phone, we have
to be constantly “on” in order to survive.
Even while sleeping our body is using
energy for activities like breathing.

How efficient are we?
How do power plants work?
How does a Hydroelectric dam
work?
How doeshttp://www.pbslearningmedia.org/asset/nvhe_vid_fission/
nuclear energy work?
How do we split an atom?
How does a nuclear power plant
work?

http://www.youtube.com/watch?v=vTHPQ
qOPg8E
Describe a stone falling off a tabletop in terms of
both kinetic energy and potential energy.
2) Give an example of an energy conversion that
produces unwanted forms of energy.
3) Describe a situation in which chemical energy is
converted into mechanical energy. Explain each
step of the energy conversion process.
4) Suppose that one air conditioner becomes very
hot when it is working but another does not.
Which air conditioner is more energy efficient?
How can you tell?
1)
Chapter 3 Questions