Types of Charges
All matter is made up atoms. Atoms contain
smaller particles: protons, neutrons, and
electrons.
11.1
11.1
Types of Charges
•
•
All matter is made up atoms. Atoms contain smaller
particles: protons, neutrons, and electrons.
electric charge
These particles have different electric charges.
Particle
electron
proton
neutron
Electric
Charge
Location
Particle
Symbol
11.1
Types of Charges
•
•
All matter is made up atoms. Atoms contain smaller
particles: protons, neutrons, and electrons.
electric charge
These particles have different electric charges.
Particle
electron
proton
neutron
Electric
Charge
+
no charge
Location
Particle
Symbol
11.1
Types of Charges
•
•
All matter is made up atoms. Atoms contain smaller
particles: protons, neutrons, and electrons.
electric charge
These particles have different electric charges.
Particle
electron
proton
neutron
Electric
Charge
Location
+
outside nucleus
no charge
In nucleus
in nucleus
Particle
Symbol
11.1
Types of Charges
•
•
All matter is made up atoms. Atoms contain smaller
particles: protons, neutrons, and electrons.
electric charge
These particles have different electric charges.
Particle
electron
proton
neutron
Electric
Charge
Location
+
outside nucleus
no charge
In nucleus
in nucleus
Particle
Symbol
ep+
n0
Charges on Atoms
•
If an atom has more electrons than protons,
negative charge and is
the atom has a ____________
a negative ion.
11.1
Charges on Atoms
•
If an atom has more protons than electrons,
positive
the atom has a ____________
charge and is
a positive ion.
11.1
Charges on Atoms
•
If an atom has the same number of protons
and electrons, the atom has no overall
neutral
charge – it is _______________.
11.1
Charges on Atoms
11.1
NOTE: Atoms can lose or gain
electrons
______________
only. The number of protons
electrons
does not change. Only _______________
can
move from atom to atom.
Charges on Objects
• An object may be positively charged,
negatively charged, or neutral.
• An object becomes charged when
electrons are either removed from
or added to the object.
• Static electricity is an imbalance
of positive and negative charges
on an object.
11.1
neutral object
negatively charged
object
positively charged
object
static electricity
Charges on Objects
Neutral object
number of protons = number of electrons
11.1
neutral object
negatively charged
object
positively charged
object
static electricity
Charges on Objects
Positively charged object
number of protons > number of electrons
11.1
neutral object
negatively charged
object
positively charged
object
static electricity
Charges on Objects
Negatively charged object
number of electrons > number of protons
11.1
neutral object
negatively charged
object
positively charged
object
static electricity
Law of Electric Charges
• A charged object exerts an electric force on a
nearby object.
• The force either attracts or repels the nearby
object.
The Law of Electric Charges states that:
– objects with like charges repel each other
– objects with opposite charges attract each other
11.1
Vocabulary
electric force
Detecting the Charge on an Object:
Electroscopes
11.1
• An electroscope is a device that is used
to detect the presence of electric
charges.
• There are two types of electroscopes:
Detecting the Charge on an Object:
Electroscopes
pith ball electroscope
11.1
Detecting the Charge on an Object:
Electroscopes
pith ball electroscope
11.1
Detecting the Charge on an Object:
Electroscopes
metal-leaf electroscope
11.1
Detecting the Charge on an Object:
How to Use an Electroscope
11.1
With an electroscope you can determine if an object is neutral or if the object
has a charge on it. You do this by observing what happens when the object is
brought close to a neutral electroscope.
Pith ball electroscope Metal leaf
electroscope
If object is neutral
If object is positively or
negatively charged
Detecting the Charge on an Object:
How to Use an Electroscope
11.1
With an electroscope you can determine if an object is neutral or if the object
has a charge on it. You do this by observing what happens when the object is
brought close to a neutral electroscope.
Pith ball electroscope Metal leaf
electroscope
If object is neutral
pith ball does not move
If object is positively or
negatively charged
pith ball swings toward
object
Detecting the Charge on an Object:
How to Use an Electroscope
11.1
With an electroscope you can determine if an object is neutral or if the object
has a charge on it. You do this by observing what happens when the object is
brought close to a neutral electroscope.
Pith ball electroscope Metal leaf
electroscope
If object is neutral
pith ball does not move metal leaves hang
straight down
If object is positively or
negatively charged
pith ball swings toward
object
metal leaves spread
apart
Applications of Static Electricity
11.1
There are many ways that we use static electricity.
Application
Science principles
involved
Electrostatic Law of electric
sprayers
charges
How the application works
This process uses less paint and no
solvents, so it is better for the environment