Transcript Slide 1

The Science
of Batteries
You will learn about:
• what’s inside a battery
• how a battery works
• how electricity moves
• the difference between
current and voltage
No. 2
First some background:
everything is made of atoms –
Wood
including this pencil
magnified
10 times
The wood is made of cells
Cells
magnified
1000 times
Cells have parts inside them,
like DNA
DNA
magnified
10,000,000
times
DNA and everything else are
made of atoms
Atoms
magnified
50,000,000
times
O
C
C
H
C
C
H
Atoms are made of a few parts:
protons, electrons, and neutrons
O
C
C
H
C
C
E
H
E
N P N
P P
N
E
The basic parts of an atom
Key
N Neutron (0)
P
Proton (+)
E
Electron (-)
The electrons spin
around the outside of
the nucleus.
The protons and
neutrons are stuck
together in the center
of the atom; this
center is called the
nucleus.
There is a lot of space
between electrons and
the nucleus.
E
E
N P N
P P
N
E
In fact, there is so much empty space
between an atom’s electrons and nucleus
that even this diagram is misleading
E
Really far apart!
N
E
P
P
N
P
N
E
To keep things simple, let’s use
this diagram for an atom
E
E
P
N
P
N
P
N
E
Sometimes Electrons Jump from
One Atom to Another
What’s all this
stuff about
atoms have to
do with
batteries?
Batteries
make
electrons jump
from atom to
atom to make
things work
The Basic Parts of a Battery
A rod of
carbon is in
the center of
the battery
A mixture called an
electrolyte (an acid
or base) separates
the carbon rod from
the zinc layer
A layer of the
metal zinc is
around the
outside of the
battery
If you connect a
wire between the 2
metals, electrons
flow from the
negative zinc to the
positive carbon
How a Battery Works
+
+
+
+
-+
+
+
-++
-+
+
-+
+
+
- - - -E- - - -
When the
carbon reacts
with the
electrolyte it
loses electrons
and becomes
positive
--- When the zinc
-- reacts with the
electrolyte, it
- steals electrons
- from the
electrolyte and
becomes
negative
In the wire, electrons are jumping
from atom to atom
E
P
N
P
P
N
P
P
E
E
P
N
P
E
N
P
P
P
P
P
E
P
E
P
N
P
N
P
N
P
P
N
N
E
N
E
N
P
P
N
P
N
E
E
N
E
N
N
P
P
P
P
N
E
E
P
E
P
N
E
P
P
P
E
E
E
E
N
P
N
E
P
E
N
E
E
N
E
N
N
N
P
P
N
N
N
P
N
N
N
N
E
E
E
P
E
E
P
N
E
E
N
P
P
E
E
P
N
E
P
N
E
E
N
E
P
E
E
P
N
N
E
P
P
N
N
N
N
N
N
N
P
N
P
E
P
P
N
E
E
N
P
N
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E
E
E
Close up
of Wire
Put something on
the wire, and the
electrons get to
work!
Battery Power!
+
+
+
+
-+
+
+
-++
-+
+
-+
+
+
- - - -E- - - -
----
Batteries
turn
chemical
energy into
electrical
energy !!
Not all batteries are the same
• One difference is how many
electrons are moving. We call this
current or amperage
• Another difference is how fast (or
with how much pressure) the
electrons are moving. We call this
the voltage
Not all batteries have the same voltage
1.5 Volts
9 Volts
High Current/Amperage
& Low Voltage
Low Current/Amperage
& Low Voltage
E
E
E
E
E
E
High Current/Amperage
& High Voltage
Low Current/Amperage
& High Voltage
E
E
E
E
E
E
A 9 volt battery is just six 1.5 volt
batteries combined together
Why Batteries Die
+
+
+
+
-+
+
+
-++
-+
+
-+
+
+
- - ---- - -
----
Batteries work
because the
metals react with
the electrolyte.
Batteries dies
when its metals
inside have
completely
reacted with the
electrolyte.
Either the metals
have dissolved
or the electrolyte
has no more
extra electrons to
push around.