Lesson 1

1 2 You will also need
a clean flat area to do the projects:
or or
Life without electricity!

It is hard to imagine.
4 Let’s review a few fundamentals
about electricity.
Electrical current
flows in a loop.

Batteries are a source
of electrical energy.

Perhaps using a battery
you have spun a motor,
lit a light bulb or LED,
or buzzed a buzzer.
5 DC Voltage
(1.5 volts)
The voltage provided
by a battery is constant.
An Oscilloscope Screen Volts Time 1

0

-1
In a battery powered circuit,
electrons flow in one direction.
This is called
DC for direct current.
DC or Direct Current
6 This is called AC
for alternating current.
DC or Direct Current An Oscilloscope Screen The voltage coming from
the wall plug alternates.
It is not flat.

It goes UP and DOWN.
7 AC versus DC - Background A Simple Explanation The Current War! 8 closed open Circuit loops,
whether DC or AC,
can be open or closed.
9 Perhaps you have built your own switch
to open and close a battery-powered
DC circuit.
With this paperclip switch
you can turn a buzzer on and off.
Wall switches
open and close
household circuits.
10 Can you test objects to determine
if they are conductors or insulators?
11 Can you build a simple series
and a simple parallel circuit?
Above and beyond everything else,
have you discovered the FUN of exploring electricity?
If you have discovered that,
then you have discovered a great deal, indeed.
12 Mankind’s initial encounters with electricity
were with static electricity -- CHARGE!

STATIC ELECTRICITY! You have likely walked across
a carpet and been shocked when
you touched an object. THAT is
13 You need to know something about
positive and negative charges
to understand electricity
or, for that matter,
to correctly install batteries.
By exploring static electricity,
scientists discovered that there are
two types of charges in our universe:
positive and negative.
14 So WHAT IS CHARGE? To begin to answer that question,
you need to know or recall
that all ordinary matter is made of particles.
15 A tiny dot made
with a sharp pencil tip
would have about
four times a billion
times ANOTHER billion
carbon atoms in it!

Now that IS small!
And all particles
are made of atoms!

How small are atoms
Click for
answer.
16 These particles
have a property called:
Each teeny, tiny atom
is made of particles.
CHARGE!!!
17 Each and every one of the billion, billion atoms
in a pencil dot
has a center or nucleus containing protons.
Protons Protons Protons are POSITIVELY charged.
18 This central nucleus or core is surrounded by electrons
that are moving about
frantically in shells.
Electrons Electrons are NEGATIVELY charged.
ELECTRICITY The charges on electrons and protons cause those sparks you experience as S T A T I C ! 20 There are
two types of charge: PLUS and MINUS.
AND these RULES apply to charges:
nucleus
with protons
LIKE CHARGES REPEL! OPPOSITE CHARGES ATTRACT! electron electron electron
21 Though it is a great deal of fun
to explore static electricity,
from sparking sparks
to making your hair stand on end,
static electricity does not supply
stable electrical power.

To get BEYOND the mere parlor tricks
of static electricity,
people had to figure out HOW to generate
a more reliable source
of electricity than just sparks.

To do that, they first figured out
how to build a battery.
22 With reliable sources for electrical power,
electronics became possible.

People discovered not only
electrical CHARGE,
but also learned
to define and measure
the key electrical quantities. . .
Voltage!
Current!
Resistance!
23 test leads Find these items
in your kit.
You have in your kit a tool
that measures all three of these: voltage, current, resistance!

Let’s charge forward and measure VOLTAGE!
LCD
screen
multimeter Find these items
around your home.
AAA, AA, C, D cells
and rechargeable
batteries (optional)
Set aside somewhat used batteries for later.
24 Set the dial
to 20 DCV
(Direct Current Voltage).
Insert the red
and black
test leads,
as shown.
The voltage
will appear
on the LCD screen
of the multimeter.
1 2 3 Press the red probe
to the positive terminal
and the black probe
to the negative terminal
of each NEW battery
to measure its voltage.
25 Record the voltages you measured
in STEP 3 in your book
or on a sheet of paper.
4 BE SURE
to turn OFF the meter
when you are finished.
What do you notice?
Use your observations
to answer the question
on the next slide.
26 Do AAA, AA, C and D cells have the same or different voltages when new How is the D cell different from a C or AA Is the voltage of
a used battery different from a new battery
Which particles carry the
negative charge in a wire
1 2 3 4 5 What is the starting voltage
of an alkaline AA cell battery
electrons the same D cells, in general, last longer. The voltage of a used battery is lower. 1.5-1.6 V
27