Download Transformations of Energy

Energy is the ability to do work. It comes in many forms and from many sources. Energy
charges your cell phone, cooks your food, lights and heats your home, and even moves your
muscles. Energy comes in many different forms. Where does energy come from, and what
happens when you use it?
Look Sandy,
energy
charges my
Blackberry!
Energy is never created or destroyed. Energy simply changes from one form to another form. This idea is called the
Law of Conservation of Energy. Electrical energy can change into heat energy. Potential energy can change into
kinetic energy. Chemical energy can turn into mechanical energy. No energy disappears when these changes
happen, but some of the energy turns into energy that you might not use, like heat. When you add it all up, the
same amount of energy exists after a
change as there was before. It is just in a different form.
Suffering
succotash!
Energy is never
created or
destroyed, this
law is called the
Conservation of
Energy!
Mechanical energy is the energy an object has because of
its motion or position. Energy of motion is kinetic energy.
The energy of position is potential energy. Potential energy is
energy that an object has stored and can use at another
time.
Potential energy can change into energy of
This
watermelon
motion if a force is used to start the object
has potential
energy
moving. A watermelon resting on the
roof of a building has the ability to fall
downward, but it will not move until
something pushes it. When the watermelon is
sitting there, it has potential energy, but no
kinetic energy.
As the watermelon falls, its potential energy changes into energy
of motion, or kinetic energy. By the time the watermelon hits the ground, it
moves fast because almost all of its potential energy changed into kinetic
energy. Right before it hits the ground, it has as much kinetic energy as it
can have, and its potential energy is zero, since it is at the level of the
ground and cannot fall farther. The watermelon stops moving when it hits
the ground. At that time, it hap no potential energy. This is because it has
nowhere farther to fall. It also has no kinetic energy because it is not
moving anymore.
Save the
watermelon!
The illustration below shows how the watermelon loses
potential energy and gains kinetic energy as it falls. The
symbol "J" represents the metric unit of energy, the joule.
The joule (J) is
the unit for
energy!
Chemical energy is the energy stored in the bonds that hold chemical
compounds together. When you turn on a flashlight, a set of energy
transformations start to take place. The flashlight batteries contain stored
chemical energy. When you turn the flashlight on, the chemical energy turns
into electrical energy that moves through the circuit inside the flashlight.
The electrical energy changes into light energy when it reaches the
flashlight's bulb. Some of the electrical energy changes into heat energy too,
and-the bulb warms up. No energy is created or lost in this process, it just
changes form.
Batteries turn
chemical
energy into
electrical
energy!
Your alarm clock goes off in the morning. You turn on the light
next to your bed. At breakfast, your toast pops up out of the
toaster, ready to eat. Each of these events was produced by
electrical energy. Electrical energy is produced by moving
electrical charges.
All day long, electrical energy changes into other forms of
useful energy. Your alarm clock plugs ,into the wall. At a
particular time, it makes a loud noise. To do this, electrical
current flows from the wall socket through the wires of the
clock. Electrical current powers the part of the clock that
makes sound. This part changes electrical energy into sound
energy. That sound energy then travels in waves through the
air. Your ear picks up the vibration and then turns that
movement into electrical energy inside your brain. Good
morning!
Electrical
energy
wakes
up your
brain!
Turning on your bedside lamp allows electrical energy to move
out of the wall socket and through the lamp. As electric
current moves through the tiny wire in the light bulb, some
energy changes into light energy. Some of the energy also
changes into heat energy, which makes the light bulb hot.
Be careful
some of the
electrical
energy turns
into heat
energy!
You can probably predict the energy transformations that happen in your
toaster. Electrical energy from the wall socket goes to the heating coils.
This energy flowing through the coils changes into heat energy. Heat
energy involves the transfer of heat from warmer objects to cooler
objects. This heat energy toasts your bread. Some energy also changes
into light energy, which you see as an orange glow. At a set time, the
toaster uses some of the electrical energy to move a spring inside the
toaster. This spring has stored potential energy, so it can move if a force is
applied to it. When your bread is toasted, the potential energy
of the spring changes into kinetic energy. The spring moves and pushes
your toast up from inside the toaster.
Many energy
transformations
occur when you
make toast
Solar energy is energy that comes from the Sun. Solar cells
mounted on rooftops can convert solar energy into electrical
energy. People then use the electrical energy for running
appliances, lighting, heating, and cooling. Solar energy can also
turn into stored potential energy if it is used to charge special
batteries that can then be used at night or on cloudy days.
I provide
solar
power!
Nuclear energy is the energy stored inside atoms, which
are the smallest particles that make up all substances. This
form of energy is used to produce electricity in nuclear
power plants. It is also used to run various kinds of ships,
including nuclear-powered submarines. Nuclear energy
powers the Sun, as well.
Nuclear
energy is
stored in
atoms!
Meep,
meep!
Describe three energy transformations
that occur in your home each day.