2. ATOMS…
Have neutrons, protons, and electrons.
Protons are positively charged
Electrons are negatively charged
3. ELECTRONS…
Are located on the outer edges of
atoms…they can be moved.
A concentration of electrons in an atom
creates a net negative charge.
If electrons are stripped away, the atom
becomes positively charged.
4. THE WORLD IS FILLED WITH ELECTRICAL
CHARGES:
+
+
-
+
+ +
+
+
+
+
+
-
-
- -
-
-
- - -
5. STATIC ELECTRICITY
The build up of an electric charge on the
surface of an object.
The charge builds up but does not flow.
Static electricity is potential energy. It
does not move. It is stored.
6. STATIC DISCHARGE…
Occurs when there is a loss of static
electricity due to three possible things:
Friction - rubbing
Conduction – direct contact
Induction – through an electrical field
(not direct contact)
7.
8. ELECTRICITY THAT MOVES…
Current: The flow of electrons from one
place to another.
Measured in amperes (amps)
Kinetic energy
9. HOW CAN WE CONTROL CURRENTS?
With circuits.
Circuit: is a path for the flow of electrons.
We use wires.
10. Static electricity is stationary or collects on the surface of
an object, whereas current electricity is flowing very
rapidly through a conductor.
11. The flow of electricity in current electricity has
electrical pressure or voltage. Electric
charges flow from an area of high voltage to
an area of low voltage.
17. THERE ARE 2 TYPES OF CIRCUITS:
Parallel Circuit – there are several
branching paths to the components. If
the circuit is broken at any one branch,
only the components on that branch will
turn off.
19. CONDUCTORS VS. INSULATORS
Conductors – material through which
electric current flows easily.
Insulators – materials through which
electric current cannot move.
21. WHAT IS RESISTANCE?
The opposition to the flow of an electric
current, producing heat.
The greater the resistance, the less
current gets through.
Good conductors have low resistance.
Measured in ohms.
22. WHAT IS VOLTAGE?
The measure of energy given to the
charge flowing in a circuit.
The greater the voltage, the greater the
force or “pressure” that drives the
charge through the circuit.
25. What is magnetism?
Magnetism is the properties and interactions of magnets
The earliest magnets were found naturally in the mineral
magnetite which is abundant the rock-type lodestone.
These magnets were used by the ancient peoples as
compasses to guide sailing vessels.
27. The earth is like a giant magnet!
The nickel iron core of the earth gives the earth a
magnetic field much like a bar magnet.
28. MAGNETS
USUALLY MADE OF IRON
EVERY MAGNET HAS A NORTH AND SOUTH
POLES
LIKE SIMILAR CHARGES REPEL
OPPOSITES ATTRACT
29. FERROMAGNETIC
OBJECTS THAT CAN BE MAGNETIZED
(IRON, COBALT, NICKEL)
3 TYPES OF MAGNETS
LODESTONE – NATURAL (PERMANENT)
ARTIFICAL – INDUCED
ELECTROMAGNET – temporary magnets
produced by moving electric current
30.
31. Ferromagnetic
material such as iron
attracts magnetic
lines of induction,
whereas nonmagnetic
material such as
copper does not.
32. Demonstration of
magnetic lines of
force with iron filings
NORTH &
SOUTH POLES
33. If a single magnet is
broken into smaller
and smaller pieces,
baby magnets result
34. A moving charge creates a magnetic field
When a charged particle is in motion – a magnetic
force field perpendicular to the motion is created
37. RT HAND RULE
Current flow direction of thumb
–
Magnetic filed – fingers
38. ELECTROMAGNET IS CREATED BY:
SOLENOID: Current flowing
through coil of wire
Putting a magnet in the
middle of the coil of wire
increases the strength of the
electromagnet’s magnetic
field
39. A coil of wire is a helix
Supplied with current it is a solenoid
Add an iron core – simple form of
ELECTROMAGNET
40. What is an electromagnet?
When an electric current is passed through a coil of wire
wrapped around a metal core, a very strong magnetic
field is produced. This is called an electromagnet.
41. HOW ELECTRIC & MAGNETIC FIELDS
INTERACT
Faraday discovered that the
magnetic lines of force and the wire
must have a motion relative to each
other to induce an electrical current
42. ELECTROMAGNET INDUCTION
Moving a wire through a magnetic field
will induce a current (Faraday)
Wire or field can move
Moving a magnet through a coil of wire
will induce an electrical current
43. “FARADAY’S LAWS : OR HOW TO INCREASE THE
STRENGTH OF THE INDUCED CURRENT
Increase the Strength of field or size of
magnet
Increase the SPEED of motion
Change the ANGLE (more
perpendicular)
Increase the Number of Turns of coil
44. ELECTROMAGNET INDUCTION
MOVING A BAR
MAGNET THROUGH A
COIL OF WIRE WILL
INDUCE A CURRENT
TO FLOW THROUGH
THAT WIRE
45. What are electric motors?
An electric motor is a device which changes electrical
energy into mechanical energy.
48. GENERATORS
A generator is a device that uses induction to
convert mechanical energy into electrical energy.
49. TRANSFORMERS
A transformer is a device used to change the
voltage in a circuit. AC currents must be used.
75,000 V in the
power lines
120 V in your
p = primary house
s = secondary
50. Transformers are
extremely useful
because they
efficiently change
voltage and current,
while providing the
same total power.
The transformer uses
electromagnetic
induction, similar to a
generator.
