to the image on the next slide.
but WHAT makes a battery, a battery?
To find out, let’s make a battery!
paper
pencil
aluminum foil
(soak in vinegar
to clean)
items from your kit.
items from your home.
(zinc coated)
washers
into a small cup
with a sprinkle
of salt added
to draw
three circles
on the paper.
Cut out the
paper circles.
or “element”
in this sequence:
square of aluminum foil,
which will become
the base.
to measure and record
the voltage of this one element.
1 circle of paper
dipped in vinegar
(damp, not too wet)
This is the electrolyte.
1 copper penny
do not have to be
too precise.
in sequence to your stack.
Measure and record
the voltage as you add
more elements.
electrolyte
copper
NOTE: Some metal combinations make stronger batteries than others.
pile light the LED
layers in each element
by Alessandro Volta in 1800,
was the first electric battery.
Its invention can be traced back
to a once-famous argument between
Volta and Luigi Galvani, a fellow scientist
who had gained notoriety
for his experiments on frog legs.
In 1780, Luigi Galvani was dissecting
a frog affixed to a brass hook.
When he touched the frog’s leg
with his iron scalpel, the frog’s leg twitched!
As you might imagine, it was quite startling.
Galvani believed the energy that drove
this contraction came from the leg itself.
He called it "animal electricity.”
with his friend’s conclusions.
He argued that the “electric”
phenomenon was caused
by the two different metals,
the brass hook and the iron scalpel,
being joined together by a moist
intermediary, the frog’s leg.
Volta set out to prove his hypothesis.
Volta did not use the frog’s leg.
Instead, he substituted a simple piece
of cloth soaked in brine (an electrolyte)
to separate a brass hook from an iron scalpel.
The completed “voltage pile” produced a voltage.
This proved that the frog’s leg was not necessary.
copper and zinc discs with an electrolyte between them,
Volta could increase the amount of electricity produced.
The result was what we call a voltaic pile, one of the first devices to provide a reliable source of electricity.
Volta gave his name to the measurement for electrical energy, the “volt.” With his discoveries, electricity went from being the parlor tricks of static electricity to becoming a major new source of energy.
you know how to generate voltage with a voltaic pile.
WHAT IS voltage?
What are you measuring and generating?
You can think of voltage as . . .
is PUSHING
the electron(s) THROUGH the wire.
This character symbolizes
PRESSURE,
electrical PRESSURE.
The electrical PRESSURE
in DC circuits comes from a constant
voltage source such as battery.
The electrical PRESSURE for AC circuits
comes from a wall plug.
Voltage pushes electrons
(the very pink Mr. Amp) through a wire.
to circuit components --
allowing a motor to spin,
a buzzer to BUZZ
or an LED to light.
for voltage is the water hose.
In this analogy, you can imagine
voltage as being like water pressure.
through a wire.
by a faucet being turned ON
is analogous to
connected to
a circuit loop
pushes electrons
(current) through
a wire.
is electrical pressure.
so electrical pressure from the battery
pushes electrons through this circuit.
it has the POTENTIAL to do work.
It is like a rock resting precariously at the top of a hill.
Some action is required
to transfer the stored energy
into another form of energy.
The POTENTIAL difference in voltage
between the battery’s two terminals
creates an electrical PRESSURE
which is measured in volts.
This PRESSURE has the POTENTIAL
to force electrons
to flow as current
when the battery
is connected to a circuit.
in a circuit, which
particles are able to flow
involved in controlling
muscle contractions
to a faucet, what part would be analogous
to a voltage source
