Download Study Guide for Electricity Presentation

Study Guide for Electricity Presentation
Basically, the rod and the electroscope are both neutral at the beginning of the
activity. When a material such as fur or fabric is rubbed on the rod, friction is
produced. The motion in a very simple picture scrapes the charges off “electrostatic
charge” or static electricity. The charge then is stuck on the rod because the rod is an
insulator. Charge may be transferred to the electroscope through contact. The
electroscope is made of conducting material so the charge on the electroscope moves
around. The charge is transferred and remains there leaving it charged until a pathway
is provided, such as the human hand, so that the charges can run off or leave the
electroscope. This neutralizes the electroscope.
When the bar magnet is on its stand, it is able to be spun by simply spinning another
magnet in your hand. This is because of the repulsion between the poles. As the
poles rotate, and they either repel or attract each other, the magnets spin in circles.
Current: is the flow of charges. Measured in (I, amps).
Conventional current: positive charges moving from the positive to the negative terminal
of a battery.
Electron current: opposite to the direction of the conventional current.
Electric current =
quantity of charge
time
I=
q (coulombs)
t (seconds)
1 coulomb
1 amp = 1 second
1.00 joule
1.0 volt = 1.00 coulomb
Ohm’s Law: the electrical potential difference is directly proportional to the product of
the current times the resistance.
1.00 volt
I
1.00 ohm = 1.00 amp
V = R (ohm’s law)
-shows the relationship between the voltage, current, and resistance.
There are two magnetic poles N and S.
Electric currents produce magnets (electro magnets).
There are three types of material conductors insulators and semi conductors. We used
conductors and insulators in the lab.
Electricity
Voltage
Current
Resistance
battery
Water Model
Height of the water (height = pressure)
water flowing
narrow tubes
pump
Miller Model
Height (roll down hill)
people moving
blocked staircases
pushing people up the stairs
Electricity
Helpful Hints
Chapter 7
Electrostatic charge an accumulated electric charge that remains at rest on an object.
Insulating materials like plastic can become charged through contact with other materials.
The build up of charge in this fashion is known as a static electricity. Electrostatic charge
can also be placed on a conductor by transferring the charge. The Van der Graaf
generator places an electrostatic charge on the conducting sphere. Often the static charge
is due to a surplus or deficiency of electrons.
Electric Conductor –
materials where electric charge is free to move throughout
the material. Usually it is the electrons in a conductor that
are mobile.
examples: copper, gold, iron (metals)
Electric Insulator-
materials that obstruct the flow of charge. Charge on an
insulator remains fixed. Electrical current cannot flow
through an insulating material.
examples: rubber, plastic, wood, glass
Electric Current-
Flow of electric charge. Just as you can measure the flow of
traffic on a highway, where the greater the flow of traffic
the more cars pass by, so increased electrical current means
more charge passes a point in a circuit.
Remember
 There are two types of electrical charge, positive and negative.
 Like chares repel.
 Unlike charges attract.
 There are two magnetic poles, north and south.
 Like poles repel.
 Unlike poles attract.
 Material can exhibit magnetic properties. Magnetic materials will act like magnets
in the presents of other magnets. Iron is a magnetic material. The metal screws are
made of magnetic material. You should have observed the metal screws acting as
magnets in the presents of permanent magnets.