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Investigating Energy
Unit 4
I.
What Are the Different Forms of Energy?
(Lesson 1)
A. Definition of Energy: the ability to cause
change
1. God uses energy to cause:
a. stars to shine
b. water to flow over the Earth’s surface
c. tiniest microorganisms to swim in a
puddle
B. Forms of Energy
1. Kinetic Energy: energy of motion
a. rain falling
b. flying bird
c. thrown football
d. you walking or wiggling
2. Potential Energy: (objects that aren’t
moving can also have energy) energy of
position or condition
a. rock on a cliff
i. it isn’t causing a change when it is on
the cliff, but if it falls, it will be
able to change objects below it.
3. Mechanical Energy: the sum of kinetic
and potential energy
a. moving bicycle
b. hockey puck flying through the air
-because of its motion (kinetic energy)
and its potential motion due to its
position above the ground (potential
energy)
4. Light Energy: visible form of energy
radiating from matter
a. without light you would not be able to
see anything
b. you see objects only when light falls
on them
c. light energy travels in waves
i.
waves have different lengths
ii.
waves travel in straight lines
through empty space
iii.
waves bend when they travel
through substances such as
glass or water
d. light energy can travel in empty space
e. living things depend on light energy
from the sun (plants use for photosynthesis)
5. Sound Energy: in the form of vibrations
that can be heard
a. sound can only travel through matter
such as air, water, or metal
b. sound cannot travel through empty
space
c. sound waves need something to
vibrate against
6. Chemical Energy: stored in bonds of the
atoms and molecules of a substance
a. depends on the arrangement of the
atoms of the substance
b. gasoline has more readily available
energy than water because of the
way molecules are arranged
c. batteries and food also store
chemical energy
7. Thermal Energy: (HEAT) the kinetic
energy of moving particles
a. faster moving particles feel warm
b. slower moving particles feel cool
c. The degree or measure of thermal
energy in an object is called
temperature
d.
e.
f.
When molecules collide, energy is
always transferred from fastermoving molecules to slower-moving
ones.
HEAT flows or is transferred in
three ways
i. Through direct contact
ii. Through space
iii. In currents through fluids
HEAT always flows from warmer
objects to cooler objects until both
are the same temperature
8. Nuclear Energy: energy that holds
protons & neutrons inside an atom’s
nucleus
a. when atoms are split or joined,
nuclear energy is released
b. nuclear energy is the same kind of
energy that supplies heat in the sun
c. weapons and nuclear plants are
based on this type of energy
9. Electrical Energy: energy of moving
electrons
a. Electrons move through wires to
power our appliances
b. Generated from many forms
i.
Burning oil or coal (chemical
energy)
ii.
Wind power (kinetic energy)
iii. Splitting atoms (nuclear energy)
iv. Solar power (thermal energy)
II. How Does Energy Change Form?
A.
Energy Conversion: the change of energy
from one form to another
1. Exploding stars
2. Erupting volcano
3. Lighting a match
4. Drop of rain falling to the ground
5. Plant leaves convert sunlight into sugar
which stores chemical energy.
6. When you play a video game, electrical
energy is converted into light energy
and sound energy.
7. The engine in your car converts the
chemical energy of the gasoline into
kinetic energy.
B.
The Law of Conservation of Energy
1. States that energy can’t be created or
destroyed.
2. Although energy is never lost, it may
be converted into a form that we
cannot use.
a. Rubbing your hands togetherchemical energy in your body is
converted to movement, but some
of the energy is changed to heat
that you cannot use.
b. A car engine is hot after it runs
for awhile because much of the
energy being converted from the
gasoline is lost as heat.
3. Whenever energy is converted, some
of it is converted to heat.
4. Some systems convert energy with
less heat loss
a. Diesel engines lose 75% of their
energy to heat
b. Car engines lose 88% of their
energy to heat
C.
James Watt
1. Born in Scotland in 1736
2. Sent to repair a steam engine
3. Developed a NEW steam engine
a. Watt figured out how to make the
steam engine turn wheels, run at
different speeds, and do many
other things.
4. The unit of power called the “watt” is
named after him.
III. What Are Our Sources of Energy?
A. Nonrenewable Resource: a resource that
can’t be replaced or can be replaced only
over a long period of time
1. Fossil Fuels: fuel that formed over
many years from the remains of living
organisms
a. From plants buried in mud, sand, and
rock
i. Energy from the sun is stored as
chemical energy
ii. To release this energy, we burn
them
iii. This burning causes pollution
2. Examples:
a. Coal
i. Coal pollutes the air more than
petroleum or natural gas
ii. Will last only 200 more years
b. Petroleum (Oil)
c. Natural Gas
3. Pollution from burning fossil fuels
a. Acid Rain – kills plants and animals
and makes water unsafe to drink or
swim in
b. Produces gases that rise into the
atmosphere and trap heat,
contributing to global warming
4. Nuclear Energy: very powerful source
of energy
a. Produced by splitting the nuclei of
uranium atoms
i. Atoms are split in a nuclear
reactor
ii. Neutrons shoot out and split
other atoms, which release
more energy. (Nuclear Fission)
b. Nuclear Fission is used to
generate electrical energy in
nuclear power plants
i. The heat produced by nuclear
fission heats water to make
steam, which turns a turbine to
generate electrical energy.
ii. Because the supply of uranium
is limited, nuclear energy is
also a nonrenewable resource.
B. Renewable Resource: a resource that can
be replaced through natural processes over
a short period of time (God provides many
renewable resources.)
1.
Solar Energy: from the sun
a. The sun heats the earth unevenly
causing wind.
2. Wind
a. Windmills
i. Used to generate electricity
ii. Used to pump water to fields
or animals on farms
3. Water
a. Falling water can produce
electricity (waterfalls, dams)
b. Tidal energy
4. Geothermal Energy
a. Built where the earth’s crust is
cracked or thin
b. Hot melted rocks called magma are
hot enough to boil water and turn
it into steam. The steam turns the
turbines to generate electricity
5. Biomass
a. Plant materials used to produce
energy
b. Spoiled crops, tree limbs, scrap
paper, corn stalks, etc.
i. Can be treated with chemical or
bacteria that change them into
fuels that can be used like
gasoline
IV. How Can We Use Energy Wisely?
A. Use electric lights wisely
B. Use less gasoline
C. Use less of things to save energy (water)
D. Recycle aluminum, pop cans, plastics, and
paper