It is recommended that you try these simple yet effective activities and
experiments at home to
help you get a better idea of the various forms of potential energy.
You can explore Energy Forms, Simple
Machines, or how energy is measured
and quantified. If
you are an educator these experiments can be used in the
classroom. Have fun!
Energy Forms
Kinetic Energy
Increase students' awareness of kinetic energy by
having them:
-
Identify objects in motion around them
-
Discriminate between fast and slow moving objects
-
Compare how various objects move (walk, roll, jump,
etc.)
-
Analyze if still objects are really moving (e.g., a
plant)
-
Investigate what makes objects move
-
Explain how muscles enable human movement
Elastic Potential Energy
Rubber Band Experiment
[picture
Materials: rubber band
A simple way to demonstrate elastic energy is to stretch
a rubber band and not let go, the stretch demonstrates potential energy. Let
go of the rubber aiming it toward a wall and it is converted to
kinetic energy.
The rubber band can also illustrate energy conversion. Place the
band against your upper lip to measure its temperature. Stretch and
release the band repeatedly. Test the temperature again. It should
feel warmer. Why does it feel warmer and where do you think the heat
energy came from?
Gravitational Potential Energy
Basketball Bounce
Materials: basketball, hard floor or pavement to bounce ball on
To demonstrate gravitational potential energy, hold a basketball
over your head and release it on to the pavement. Gravity pulls the
ball towards the Earth creating kinetic energy as it drops until it
hits the pavement converting it back to potential. This conversion
from potential to kinetic is repeated as the ball bounces up and down
the pavement.
When you drop the ball, note how high it bounces back. Why doesn't
it bounce back to the same height at which you let it go? If you let
the ball keep bouncing, notice that with it bounces back a little
lower each time.
If the ball were to bounce back to the same height at
which it was dropped, that would mean all the gravitational energy was
converted to kinetic energy. It isn't all movement, though is it?
Listen (that's a hint), what other forms of energy can you detect or
identify? Think back, too, to the rubber band experiment--can you
think of another energy form?
Roll-back Toy [add picture of steps]
Materials:
- A small container that can be laid on its side and rolled and
have a hole punched in its top and bottom (such as a clear plastic
soda bottle or coffee can)
Note: Using a clear soda bottle helps to
demonstrate what
is happening inside.
- One thick rubber band about 3-4 inches long (8-10 cm)
- Two tooth picks or paper clips
- Several washers tied together with a twist tie or another
weighting device that will fit through the opening of a soda
bottle or the container being used.
- String
- Hole punch tool or scissors
Procedure: Punch a hole through the
lid and the bottom of the container. Take the lid off the container.
Thread a string through the bottom of the container and pull it
through the lidless top of the container (make sure there is still
string hanging out the bottom end).
Tie the end of the string that you pulled through the top to one
end of the rubber band (you will use the string as a lead to help
thread the rubber band through the container).
Tape the washers together and
then connect them to the middle of one section of the rubber band (do
not tape the strands of the rubber band together).
Put the end of the rubber band (the end not connected to the
string) through the container lid. Use a
toothpick to secure the band so that it does not slip inside the
container (put the toothpick through the end loop of the rubber band
that remains outside the hole). Put the lid on the container (making
sure the string is still sticking out the other end).
Carefully pull on the thread until the rubber band comes through the
hole. Secure the band with the second tooth pick. Be sure to situate the weight so it is in the center of
the container and does not touch the sides. Your roll-back toy is ready to go!
Activity: Roll the toy and watch as the weight holds one
strand of the rubber band stationary while the free side twists around.
The farther the toy is rolled the more potential energy.
Release and watch the toy roll back towards you demonstrating kinetic
energy. This would be a great activity to have races in the classroom
to see who could devise the roll-back toy with the greatest potential
energy.
Chemical and Mechanical Energy [picture]
Rocket Experiment
Materials: plastic flask, cork, 1/2 cup water, 1/2 cup vinegar, spoonful of
baking soda, paper coffee filter, empty film canister (or
non-childproof prescription bottle, candy tube, or empty
glue stick)
Note: Only attempt this activity where this is overhead space and
room to move away.
Pour a 1/2 cup of water and a 1/2 cup
of vinegar into the flask. Put a spoonful of baking soda into a coffee
filter, roll and twist it closed. Put the coffee filter in the flask,
cork it and move away...fast! Both the baking soda
and vinegar contain molecules (which have potential energy in their
bonds). When mixed
together the bonds break and the molecules rearrange themselves to
produce a gas releasing energy. The continued production of gas in a
closed container increases the pressure (potential energy) in the
container. This experiment
demonstrates chemical energy converted to mechanical energy or
movement.
Design an EMPTY film canister (or non-childproof
prescription bottle, candy tube, glue stick) to look like a rocket (add fins, nose cones,
etc.). Put a little baking soda and vinegar in the rocket and quickly
close the lid and invert. Lift off! (NOTE: You'll need to use the type
of canister where the lid fits inside the canister rather than the cap
style.)
Volcano Experiment
Materials: small amount of vinegar and baking soda, container for
experiment
Simply pour a small amount of vinegar onto baking soda causing a
chemical reaction. Again, when mixed
together the bonds break and the molecules rearrange themselves
releasing energy. (Taken from
"Potentially Kinetic,"
KEEP Energy Education Activity Guide.)
Chemical and Electric Potential Energy
Flashlight Experiment
Chemical
and electric potential energy can be demonstrated through a battery in
a flashlight. In batteries chemicals are used to separate electrons (-
charge) from protons (+ charge), momentarily moving them. The
separated positive and negative electric charges of a battery
represent another form of potential energy called electric potential
energy. When a battery is connected to an electrical circuit (such as
a flashlight being turned on), the electrons leave the negative
terminal of the battery and move (flow) through the circuit to the
positive terminal.
In energy terms, electrical potential energy
in the battery is converted into kinetic energy of moving electrons.
Think back to the waterfall analogy used to discuss voltage and
current. The voltage is the height of the water fall and the current
is the falling water (flowing electrons). The electrons' kinetic energy is then converted into another form,
such as light with the flashlight. (taken from "Potentially
Kinetic More About Batteries,"
KEEP Energy Education Activity Guide.) Sound Energy
Good "Sound" Vibrations Experiment
Materials: bowl, plastic wrap, rubber band that fits over bowl,
pinch of salt, metal bowl, spatula Sound is caused by vibrations
that moves air molecules in waves. To demonstrate that sound waves
move through the air cover a bowl with plastic wrap and secure it with
a rubber band. Sprinkle salt over the plastic wrap. Over the bowl with
sprinkled salt clang a metal pot with a spatula. The sound vibrations
from the clanging will cause the air molecules to move causing the
salt on the plastic wrap to move. Materials: Plate, rice, stereo
with speakers Sprinkle the rice on a plate and
place it on top of a stereo speaker. Turn the music on (preferably a song
with a loud bass). Watch the rice dance!
Speed of Sound
Sound travels faster through metal and brick than it does in air.
To demonstrate this, find a brick or metal building. Have one student
place one ear on the building. Have another student stand around a
corner and loudly talk into the brick of the building. The student
with his or her ear on the building should hear the message in the ear
placed on the building first before he hears it with the air exposed
ear.
Sound Wave Experiment
Materials: piece of paper, two metal spoons Sound waves bounce
off objects obstructing them causing an echo. To demonstrate that
objects obstruct sound waves roll up a piece paper and hold the one
side to your ear. Have someone stand behind you and hit two
spoons together behind your left ear, your right ear, and above your
head. The ear that has the paper held up to it will not be able to
pick up the sound waves from the spoons being tapped above your head,
so you will think it is coming from behind the unobstructed instead.
Other "Sound"
Ideas
-
Associate sound with vibration (observe how vibrating
objects produce sound and how sound causes objects to vibrate)
-
Compare how sound travels through different objects
-
Contrast the sounds made by different objects
-
Demonstrate how sound travels (via vibration) through
solids, liquids, and gasses (air)
-
Diagram how the vocal cords produce sound
-
Explain how the ears transmit sound (through the ear
canal to nerve cells so the brain can interpret the sounds)
-
Create instruments that generate different types of sound
- Students can keep a Sound Log where they notice
noises common and unique to each day.
Light Energy
Increase students awareness of light energy
by having them:
-
Identify sources of light
-
Examine how light reflects off different objects
-
Discriminate among transparent, translucent, and opaque
materials
-
List the colors of the rainbow
-
Compare how different colors absorb light (radiation)
-
Diagram parts of the eye and explain how it transmits
light (to nerve cells to the brain so it can interpret what you see)
-
Read students a story and have them tally the
times motion, light, sound, or heat is mentioned.
-
Use a radiometer
to show that light has energy.
Thermal
Energy and Heat Explorations How Heat Travels through
Conduction
Spoon Experiment
Materials: spoons made of various materials (like aluminum,
stainless steel, wood, or plastic), saucepan of hot water (Use caution
with the water.) First place a metal spoon in the water for a few
minutes, then feel the end sticking out of the saucepan. It should feel
warm because of conduction. Next, place all the spoons made from
different materials in the saucepan. After a few minutes, touch the
handle tips of each spoon and determine which is the hottest and why.
Students can arrange spoons from best to worst conductors and discuss
why (Taken from "Exploring Heat,"
KEEP Energy Education Activity Guide.) How Heat Travels through Convection
Spiral Experiment
Materials:
paper, scissors, string, incandescent light bulb or other heat source
such as a candle or radiator. Cut a spiral or coil out of the piece
of paper and tie a string to the end of the spiral. Hold the coil
above the heat source. The heated air moving by the process of
convection will cause the paper to spiral. Caution: Incandescent light
bulbs get very hot. If you are using a candle, hold the coil and make
sure the paper does not touch the flame. (Taken from "Exploring
Heat,"
KEEP Energy Education Activity Guide.) Thermal Energy and Expansion
Balloon Expansion Experiment
Materials: saucepan filled with hot water, oven mitts or gloves,
empty glass bottle (such as a ketchup bottle), rock or a weight to
hold the bottle down, balloon Put a balloon over the top of an empty
ketchup bottle (you may need to put a rock in the bottom of the bottle
for weight). Place the bottle in a saucepan of hot water. The balloon
should expand because the air inside the bottle gains thermal energy
and the molecules move around more, filling the space inside the
balloon. (Note: If this experiment is performed in the classroom, the
teacher should place the bottle in the water as it gets very hot.
(Taken from "Exploring Heat,"
KEEP Energy Education Activity Guide.)
Penny Experiment
Materials: glass bottle with opening no larger than a penny, one
penny, bowl of ice cold water. Dip the penny and the threads of the
bottle neck in the cold water. Put the penny over the opening of the
bottle and wrap hands around the bottle until the penny jumps. The
heat from your hands is transferred through conduction to the air in
the bottle warming the air. This causes the air molecules to move
faster which makes the penny jump.
Energy and Simple Machines
The main understanding for students to achieve
during simple machines unit is that the tools change the direction of
a force. Machines change the state of energy to produce work. Work is
force multiplied by distance. Another way of saying this is that humans use
their energy with simple machines to do work by changing the state of
energy of the object (system) they're working on (e.g., from
potential to kinetic).
The result of simple machines is that the same
amount of energy is transferred (used), but because the effort is less
it is often confused with using less energy. Machines make the effort easier
for humans, but the same amount of work is done. Simple machines also
make work easier because they use less power (i.e., they are faster
and require less time; they increase the speed at which the work is
done). Students might have heard the term "powerful" used with
certain automobiles. It is powerful because the engine allows the car
to increase from 0 to 60 mph in less time.
It might be too difficult to introduce the role
of energy in the Simple Machines unit; however, the following
challenge could help students consider energy transfer when examining
how simple machines "work". The main objective of this exercise is
to help students who equate energy with effort or with force and this
is not a scientifically accurate use of the term energy. Of course, in
everyday language, these applications are acceptable.
Challenge Question:
[Graphics
would really help this activity]
A person is directed to put a heavy box that is on rollers onto the
back of a truck. She can lift the box to the truck, use a steep ramp,
or a ramp that is less steep.
Ask students:
-
Which simple machine does the ramp represent?
-
Which method they would choose and why? Notice if they
use the term "energy" in their answers.
-
Which method gets the most work done? Trick question,
the work is essentially the same. Work = Force x Distance. (Because of
friction force, there would be some minimal difference among the
methods.)
-
Which method uses the most energy? Another tricky
question, with any of the methods the box ends up at the same height,
so whatever amount of energy is transferred is essentially the same.
The individual might need to use more effort to lift, pull, or push
the box with the steeper ramp (or with no ramp), but the energy
transferred to the box is the same no matter which method is employed.
Students can simulate the challenge by securing a weight (such as a book
or a paperweight) to a large toy car or truck. Tie a rope around the
truck and weight. Tell students they are to move the truck and weight
from the ground to the top of a box (they should pull the object by
the rope). Provide students with different length boards to serve as
ramps (steep and gentle slopes). Have students use a spring scale to
measure the differences in force among the various options.
Energy Can be Measured
and Quantified Click the energy bill to show how
energy measurements show up on your utility
bill.
Next reading:
What is Energy? -
Section E.
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