|
|
"Energy
Show" (Senior)
Return to Science Shows
Program:
St Joachim's (Angela Alibrando), St Jude's (Jenny Chalker), Christine
Bellert & Kate Lorkin (St Anne's).
Presentation:
Equipment:
- Flash cards
with different types of energy forms [sound, light, heat, movement,
gravity, electricity, magnetism, solar, chemical, wind and hydroelectricity].
- Blue tack for
flash cards.
- Metal tin and
nails.
- Balloon and
pins.
- Radio.
- Retort stand,
clamp, scissors, paper clips, masking tape and magnet.
- Solenoid, bar
magnet, 2 wires and galvanometer.
- Paper clips,
battery, 2 wires, wire-wrapped nail.
- Candle and matches.
- Matches.
- 3-4 types of
food.
- 2 retort stands,
string and 2 small ring weights.
- 2 sets of string-weight-string-weight
- straw, nylon
thread, masking tape, long balloon.
- torch.
- rubber band.
- rubber ball.
- Cup, thermos
of hot water, spoons [metal, plastic and wood]
- 3 bowls of water,
hot and cold water.
- straw, string
and rod.
- Van der Graff
generator, wand, plastic bucket, pieces of paper, aluminium plates.
Notes:
"Hello everyone.
Has anyone seen Ralph. He is around here somewhere. He said he will
help me set up today but whenever there is work to do he always hides.
Anyone seen him?
He's so lazy ... he never seems to have much energy. I tell him every
morning to eat his cereal. He loves Cocoa-pops. Anyone like Cocoa-pops?
Its great. It gives you lots of energy. That is very funny actually
because I have been asked to come here to talk to you guys about energy.
Energy is very important to us every day. We use energy all the time
and we don't even know it. There are many forms of energy around us
and I have some words that might help us in finding these types of energy.
The problem is I got all these cards mixed up when I was coming over
and I can't remember which card matched which picture. Can you help
me?
Match them up
activity: Flash cards with the correct type of conversion of energy
...
| Energy
form |
Example |
| sound |
radio |
| light |
candle |
| movement |
person running |
| gravity |
apple from
a tree |
| electricity |
lightning |
| magnetism |
horse shoe
magnet |
| solar |
sun |
| chemical |
bomb |
| wind |
windmill |
| hydroelectricity |
dam |
There is energy
in the food we eat ... there is energy in petrol that we put into cars
... there is energy in turning on a light switch ... there is energy
used when we open a door and many other ways. What we are going to do
is look at a few kinds ot energy that we see every day around us. But
I need you help. The most important thing is that energy is something
that we all need and can use. It is important that we use it and to
know where it came from in the first place. The reason we can get up
every morning and go to school to learn and have fun is because we keep
refuelling ourselves with food. Like putting petrol into cars to make
them work. Without the petrol cars will not run. We have to do the same.
How many times have your heard your Mum or Dad say "You must eat
all your dinner first".
We will look at
different types of energy and how they might change from one form to
another.
Demonstrations:
|
Type
of energy
|
Demonstration
|
Equipment
|
Energy
conversion
|
| Sound
energy |
Tin
filled with nails: Shake it really loud! What is happening?
Energy is changing from one form to another ... movement energy
to sound energy. |
Metal
tin and nails. |
Movement
to sound energy |
| Sound
energy |
Popping
a balloon with a pin: Why does it stay round? The air particles
on the inside collide with the elastic rubber balloon at the same
rate as the air particles on the outside. The forces are the same. |
Balloon
and pins. |
Elastic
potential energy to movement and sound energy |
| Sound
energy |
Radio:
Turn on a radio. |
Radio. |
Electrical
energy to sound energy. |
| Magnetism |
Magic
Magnets: Suspend a paperclip attached to string from a retort
stand with a magnet at the top. How does it stay there? |
Retort
stand & clamp, string, scissors, paper clip, masking tape and
magnet. |
Magnetic
energy & gravitational energy. |
| Magnetism |
Generating
electricity: Creating electricity with a solenoid, bar magnet,
2 wires and galvanometer. |
Solenoid,
bar magnet, 2 wires and galvanometer. |
Movement
to electricity energy |
| Magnetism |
Generating
magnetism: Connect a wire wrapped around a nail to a battery
and see if it picks up paper clips. |
paper
clips, battery, 2 wires, wire-wrapped nail |
Electrical
energy to magnetism energy |
| Chemical
energy |
Candle
burning: Light a candle. |
candle,
matches |
Chemical
to light and heat energy |
| Chemical
energy |
Lighting
a match: Light a match. Sulphur on the match. |
matches |
Chemical
to light and heat |
| Chemical
energy |
Examples
of good energy foods: apple, ... |
3-4
types of food? |
Stored
chemical energy |
| Movement
energy |
Standing:
Standing still, marching or jogging on the spot. Anything that moves
has movement energy. |
3
students |
Chemical
energy (food) to movement energy |
| Movement
energy |
Coupled
pendulum: String with 2 pendulum suspended of it. |
2
retort stands, string and 2 small ring weights |
Movement
energy to stored energy |
| Movement
energy |
Which
will break? 2 sets of weights held together with strings and
pulled slowly and then fast. Which will break |
2
sets of string-weight-string-weight |
Inertia |
| Movement
energy |
String
rocket: Rocket on nylon thread across the room |
straw,
nylon thread, masking tape, long balloons. |
Elastic
potential energy to movement energy. |
| Light
energy |
Torch:
Turn on a torch. |
torch |
Chemical
to light energy |
| Light
energy |
Sun:
Look out the window. |
- |
Nuclear
to light and heat energy |
| Elastic
potential energy |
Fling
a rubber band |
rubber
band |
Elastic
potential energy to movement energy |
| Gravitational
potential energy |
Drop
a ball: Gravitational energy and elastic potential energy in
the bounce. What happens when it bounces? Why does it come back? |
rubber
ball |
Gravitational
energy and elastic potential energy to movement energy |
| Heat
energy |
Rubbing
hands together: Rub your hands together. What happens? Friction
makes heat. |
- |
Movement
energy to heat - friction |
| Heat
energy |
Spoons
in a cup: Place a wooden, plastic and metal spoon in a cup of
very hot water. Which one is hottest? Better conductor of heat. |
Cup,
thermos of hot water, spoons [plastic, wooden and metal] |
Heat
transfer processes |
| Heat
energy |
Three
bowls: Place your hands into 2 outer bowls or cold and warm
water. Then place them separately into the middle luke warm water.
What does each hand feel? |
3
bowls of water, hot and cold water |
Heat
transfer processes |
| Wind
Energy |
Kissing
Balloons: 2 balloons on string suspended from each end of a
rod. Blow with a straw in between and they come together. |
straw,
string, rod |
Wind
energy to movement energy |
| Electrical
energy |
Van
der Graff generator: Get a spark off the Van der Graff and stand
a student in the bucket with hands on it. |
Van
der Graff generator, wand and bucket. pieces of paper and aluminium
plates. |
Electrical
energy to movement energy. |
Topic notes:
Professor Cludd
presenting information related to "Energy". Students
could be able to:
- state what energy
is.
- state what force
is.
- identify changes
that take place after forces act in common situations.
- identify energy
as either movement energy or potential energy.
- identify different
forms of energy (see below).
- identify the
main sources of energy on the Earth.
- describe two
main sources of fuel used by humans.
- describe energy
conversion involved in some simple energy converters.
- describe one
way to store energy.
- describe the
ways in which we get energy from food and drink.
Some of the topics
could include ...
1. Types of
energy:
- Chemical energy
- Electrical energy
- Light energy
- Sound energy
- Heat energy
- Kinetic (movement)
energy
- Nuclear &
Atomic energy
- Gravitational
potential energy
- Elastic potential
energy
- Solar energy
- Wind energy
- Hydroelectricity
- Geothermal energy
- Magnetism
- Wave Energy
Introduction
to Energy:
Understanding
forces: Many everyday activities include some of the words lifting,
pushing, pulling, stretching, squashing, bending, twisting or tearing.
Forces can make an object move. When a jet plane takes off the push
of the gases out of the engines forces the plane forward. There are
also forces that slow things down ... friction is an example which is
useful in brakes or a parachute. Forces may also change the shape of
things, like the force during a car collision with a light pole or the
compression of a soccer ball when you kick it. Some forces act at a
distance like gravity, magnetism or electrostatics. Other forces need
to be in contact with the object to work such as explosives. A force
does not necessarily make something change its shape or move differently.
When we push against a wall there are forces acting ... the amount of
force pushing on the wall is balanced by the amount of force the wall
must push back on you otherwise the wall will collapse.
Understanding
energy: There are many types of energy that exist in our lives.
There is a term used to describe the physical affect that occurs when
a type of energy is used up ... this term is called "work".
Scientists say that energy is the ability to do work. Work can be your
legs making pedals on a bike turn so that you move forward ... it could
be getting out of bed ... chopping wood ... and a light globe turning
on. In summary, forces change or try to change the way things move.
They may speed something up, slow it down or make it change direction.
They may also change or try to change the shape of something. Work is
done on an object when a force acts on an object moves it. Energy is
a measure of an object's ability to do work.
Measuring energy:
Energy is measured in Joule (J) just like length can be measured in
metres (m) or speed in km/h. It came from the British scientist who
lived during the 19th century James Prescott Joule. What does the size
of the units indicate? One Joule of energy is used to lift a 100g mass
up in the air 1 metre. The number of Joule humans use is much larger
than 1 Joule. We often work in MegaJoule which is 1 million Joule. Here
are some common energy amounts to compare with ...
| Activity |
Energy
in Joule (J) |
| Energy
used when burning a match |
10,000J |
| Movement
energy of a car on a country road |
500,000J |
| Energy
used to walk 5km |
1,000,000J |
| Energy
used in an electric heater for 10 minutes |
1,200,000J |
| Electrical
energy stored in a car battery |
2,000,000J |
| One
day's hard work |
3,000,000J |
| Energy
needed for a growing boy per day |
13,000,000J |
| Energy
used by a typical family in a day |
170,000,000J |
| Energy
stored in 5 litres of petrol |
200,000,000J |
| Energy
made by a large power station every second |
2,000,000,000J |
Food energy:
The energy needed by our bodies come from the food we eat. Energy stored
in food in measured in kilojoule (kJ). Information about the amount
of energy contained in various fodds is important in determining a balanced
diet. A diet that will provide us with the correct amount of food necessary
for our daily energy requirements but will not make us fat is a balanced
diet. Below are some common kilojoule values for foods ...
| Food |
Energy
in kilojoule (kJ)
|
| Teaspoon
of sugar |
80
|
| Piece
of fresh fruit |
193
|
| Slice
of bread |
235
|
| Two
plain sweet biscuits |
285
|
| An
egg |
301
|
| Slice
of fruit cake |
637
|
| Glass
of milk |
645
|
| Small
lamb chop |
1279
|
Potential energy:
Energy can be stored in a car battery, a bomb, a litre of petrol, an
apple, or a wound up spring. The form of energy these have is called
potential energy. It has the potential to change to another form of
energy. An example might be a wound up spring would release its energy
and fire a toy off. Potential energy is a form of stored energy. All
objects have a greater gravitational potential energy when they are
at a higher point.
|
Chemical
energy
|
Electrical
energy
|
|
Activities:
- Light
a match (movement to heat from friction)
- Lighting
a candle (chemical energy to heat and light energy)
|
Activities:
- Lemon
battery (chemical to electrical energy)
- Investigate
the workings of a torch (chemical to electrical energy to light
energy)
|
| Theory:
Fuels, explosives and all food have stored chemical energy. Petrol
is mixed with air and burnt releases an explosive burst of energy
that forces the pistons within the motor car engine to down which
in turn drives the drive shaft of your car in order for it to move
forward. The food we eat gives us the energy everyday to move and
live. Explosives can be used in mining to blast huge holes in the
sides of hills to extract metal ore. |
Theory:
Electrical energy can be stored in a car or alkaline battery. Chemical
reactions inside the battery automatically occur when you connect
a wire from the positive to the negative terminals. If there are
circuit components connected between these wires the electricity
passes through them also transferring their electrical energy to
these components. Light bulbs can glow, radio speakers can deliver
sound and electric motors can operate. We use a large amount of
electrical energy every day in many appliances we use. |
|
Sound
energy
|
Heat
energy
|
|
Activities:
- Shake
a tin full of nails (movement to sound energy)
- Turn on
a radio (movement to sound energy)
|
Activities:
- Rub your
hands together (movement to heat from friction energy)
- Investigate
how a kettle's filament works (electrical to heat energy)
- Radiator
(electrical to heat energy)
- Turn on
a gas stove (heat to chemical to heat energy)
|
| Theory:
The speeding up of vibrating air particles results in high sound
energy. The greater the vibrations, the louder it becomes. We need
air particles to collide off each other to transmit a sound wave
from the source to our ears in order for the sound to be heard. |
Theory:
Heat energy is to do with the nature of the movement of particles
within an object. If they are moving rapidly then their temperature
is high. It is found that at -270 degrees celcius all movement of
all particles in the universe would stop. When we touch something
that feels warmer than our hand the particles of the warmer object
are moving faster than the particles on our hand. This is the sensation
of warmth. |
|
Nuclear
& Atomic Energy
|
Gravitational
Potential Energy
|
|
Activities:
-
|
Activities:
b
- Drop a
ball to the ground (gravitational energy to kinetic energy)
|
| Theory:
Only as recently as the 1940's did nuclear energy become available
to us through the discovery of the technology needed to extract
the energy. A huge amount of energy is released when the nucleus
of atoms is smashed open. Almost 10,000 times the strength of any
chemical explosion. Nuclear reactions use a controlled nuclear reaction
to generate heat that turns water to steam. This steam is forced
through turbines (like a steam engine) that generate electricity.
The devastating power of nuclear energy can be seen in the dropping
of the bombs on Hiroshima and Nagasaki during World War II. Many
nuclear reactors nowadays are used to generate nuclear material
for help in diagnoses and treating illnesses in patients, particularly
cancer. |
Theory:
One important type is gravity (or gravitational potential energy).
If a pencil is pushed off a table onto a seat it is pulled downwards
and speeds up until it hits the seat. The amount of energy due to
gravity for the height from the table to the seat is completely
converted into movement (kinetic) energy. Its maximum speed is just
prior to hitting the seat. If it then rolls off the seat onto the
ground the same thing happens. The amount of energy due to gravity
for the height from the seat to the ground is completely converted
into movement (kinetic) energy again. You can actually calculate
the final speed any object will travel just prior to hitting the
ground by the square root of the value (20 x d) where (d) is the
height the object falls through. The units are in metre per second
which can be converted to kilometres per hour by multiplying this
value by 3.6.
Example:
If a rock was dropped from the top of a 200m building the final
speed just prior to hitting the ground will be the square root
of (20 x 200) = the square root of (4000) = 63.2 metre per second.
In kilometes per hour this is 3.6 x 63.2 = 228km/h. Quite fast!
All objects
are pulled towards the centre of the Earth with a large force
... in fact towards the centre of any object that has a mass.
Two people standing next to each other have a force of gravity
pulling each other together! Because the masses of the two people
is so small (compared to planets!) you cannot detect much gravity
force. A black hole is so densely packed that even light is drawn
into due to gravity. Since light cannot escape it it is not observable
and is therefore a black object. This is why it is called a black
hole. It is so dense that is it like squashing the Earth down
into the size of a golf ball!
Gravity can
also be used to generate other forms of energy. Water stored in
dams can be released downhill through a dam. The water makes the
turbines spin around generating electrical energy that can then
be transported to us for use in our homes.
|
|
Solar
Energy
|
Wind
Energy
|
|
Activities:
- Feel the
warmth of the morning or afternoon sun in and out of shade (solar
energy to heat energy)
- Investgate
plants growing in and out of the sun's light (solar to chemical
energy)
|
Activities:
- Make a piece of
paper move (wind energy to movement energy)
- Blow on a made windmill
(movement energy to wind energy)
|
| Theory:
The sun carries with it a lot of energy. The main use of solar energy
on our planet is to convert solar energy into a form plants use.
Plants absorb solar energy by a process called photosynthesis. Over
exposure can also be damaging to our skin or eyes. That is why sun
glasses and sun block are important to us. |
Theory:
Strong winds are a form of kinetic energy. During the cyclone of
Darwin many years ago a lot of damage to buildings and property
was evident. |
|
|
|
|
Activities:
b
|
Activities:
b
|
|
Theory:
Strong magnets can be used to do work in scrap metal yards. If
you connect the positive and negative terminals of a battery to
each other electricity naturally flows through the wire. If you
get the wire and wrap it tightly around a long metal nail and
connect the two ends to the battery, electricity passes through
the wire as normal. As a side result the coiled wire then becomes
an electromagnet. Placing anything metallic near it will be attracted
to the nail. This is how a simple electromagnet works.
The Earth
spins on its axis. As a result of this it creates a magnetic field
within itself. This is why the Earth has a magnetic field with
the north pole up top and the south pole down south.
|
Theory:
Gravity can be used to generate other forms of energy. Water stored
in dams can be released downhill through a dam. The water makes
the turbines spin around generating electrical energy that can then
be transported to us for use in our homes. The energy is stored
high up in the river above. When it falls through the height of
the dam it transfers it stored potential energy into movement (kinetic)
energy which turns the turbines. These turning turbines generate
electricity like the old dynamos on bike tyres. The Snowy Mountain
scheme was a good example of this. |
|
Light
energy
|
|
|
Activities:
- Turn on
a torch (electrical to light energy)
- Strike
a match (movement to heat and light energy)
|
Activities:
- Bounce
on a trampoline (elastic potential energy to movement energy)
- Fling
a rubber band with your fingers (elastic energy to movement
energy)
|
| Theory:
Another name for light is electromagnetic waves. Only a small amount
of the electromagnetic spectrum can be seen by the human eye: this
part is called the visible spectrum. The electromagnetic spectrum
has many purposes: laser beams, communication, TV and radio, x-rays,
microwaves and infra red. |
Theory:
Elastic potential energy is stored in springs and elastic energy.
When we wind a clock up the stored energy in springs is slowly used
to work the clock mechanism. The use of a trampoline converts movement
energy into elastic potential energy and again turns it back into
movement energy when we bounce back up again into the air. |
|
Kinetic
(movement) energy
|
|
|
Activities:
- Walk around
slowly and then fast (chemical energy (food) to movement energy)
- Throw
a ball (chemical energy (food) to movement energy)
|
Activities:
- Make waves
in a bucket of water (movement energy to wave energy)
- Speak
so that someone can hear (movement energy to wave energy)
|
| Theory:
Kinetic energy is the energy on object has because of its movement.
Some things have very large amounts of kinetic energy as in the
case of a rapidly moving train. This can cause a lot of damage if
it collides. The amount of kinetic energy it has will be converted
to the target it hits. |
Theory:
Waves carry energy from one point to another. Water waves can
carry a surfer to shore or damaging the coastline and sound waves
can carry sound energy to someone's ears making the ear drum move
back and forth. Another name for light is electromagnetic waves.
Only a small amount of the electromagnetic spectrum can be seen
by the human eye: this part is called the visible spectrum. The
electromagnetic spectrum has many purposes: laser beams, communication,
TV and radio, x-rays, microwaves and infra red.
The other
form of wave energy is earthquakes.
|
Main sources
of energy: (to come)
Non-renewable
energy sources: (to come)
Changing and
storing energy: Almost all energy we use today comes indirectly
from the Sun. Most of the energy reached the Earth millions of years
ago and is now stored in the form of coal, oil or natural gas. This
form of stored energy must be converted into other forms of energy to
be useful for factories, homes, communication and transport. The change
of energy from one form to another is very important. Below are a number
of examples of energy conversions that are important to us...
|
From
|
Kinetic
energy
|
Gravitational
energy
|
Electrical
energy
|
Chemical
energy
|
Heat
energy
|
|
Kinetic
energy
|
Gearbox
of car
|
Stone
rolling down a hill
|
Electric
train
|
Gunpowder
exploding to fire bullets
|
Steam
engine
|
|
Gravitational
energy
|
Lift
going up
|
.
|
Electric
motor in a lift
|
.
|
.
|
|
Electrical
Energy
|
Bicycle
generator
|
Hydroelectric
power station
|
Transformer
|
Battery
being made
|
.
|
|
Chemical
energy
|
.
|
.
|
Battery
being charged
|
.
|
.
|
|
Heat
energy
|
.
|
.
|
Elements
of a electric hotplate
|
Gas
stove
|
Heat
exchanger
|
When energy changes
from one form to another some of the energy is lost. How well a radiator
or car converts this full amount of energy to its purposeful use called
its efficiency. The efficiency can be expressed as a percentage. Other
examples of energy converters could include the following ...
|
Initial
form of energy
|
Energy
converter
|
Final
form of energy
|
|
Electricity
|
globe
|
light
|
|
light
|
solar
cell
|
electricity
|
|
electricity
|
loudspeaker
|
sound
|
|
sound
|
microphone
|
electricity
|
|
chemical
energy
|
jet
engine
|
movement
|
|
electricity
|
electric
motor
|
movement
|
Friction:
Another main form of loss of energy can be in friction. A car has a
lot of moving parts. Many of these moving parts are lubricated by engine
oil which helps to reduce the energy lost by parts rubbing against each
other. Rub your hands together. Do they feel warm? This is a simple
example of frictional energy. Movement energy is lost to form heat in
the rubbing action of your hands. Many other ways are devised to try
to reduce friction in transport ... stream lining, lubrication, reduce
the number of moving parts, reduce the weight etc. Friction also causes
wear and tear.
Storing electrical
energy: A devise that stores energy has always been of great use.
Devices such as chemical cells can store energy. Small batteries are
used to provide energy for many appliances such as calculators, torches,
clocks and radios.
|
