Transcript Do Now - White Plains Public Schools

What is Static Electricity?
Everything we see is made up of tiny little parts called atoms.
The atoms are made of even smaller parts. These are called
protons, electrons and neutrons. They are very different from
each other in many ways. One way they are different is their
"charge." Protons have a positive (+) charge. Electrons have
a negative (-) charge. Neutrons have no charge. Usually,
atoms have the same number of electrons and protons. Then
the atom has no charge, it is "neutral." But if you rub things
together, electrons can move from one atom to another.
Some atoms get extra electrons. They have a negative charge.
Other atoms lose electrons. They have a positive charge.
When charges are separated like this, it is called static
electricity.
 If two things have different charges, they attract, or pull
towards each other. If two things have the same charge, they
repel, or push away from each other.
 So, why does your hair stand up after you take your hat off?
When you pull your hat off, it rubs against your hair.
Electrons move from your hair to the hat. Now each of the
hairs has the same positive charge. Things with the same
charge repel each other. So the hairs try to move away from
each other. The farthest they can get is to stand up and away
from all the other hairs.
If you walk across a carpet, electrons move from the rug to
you. Now you have extra electrons. Touch a door knob and
ZAP! The electrons move from you to the knob.You get a
shock.
Static electricity
Static electricity is a
buildup of charge on an
object.
Static Electricity
 Like charges repel – unlike charges attract
 Positive (+) and Negative (-) charges attract
or pull.
 Positive (+) and Positive (+) charges repel
or push.
 Negative (-) and Negative (-) charges repel
or push.
http://amasci.com/emotor/vdgde
mo.html
 Some atoms hold on to their electrons more tightly than
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others do. Positive items in the series are at the top, and
negative items are at the bottom:
Human hands (usually too moist, though) Very positive
Rabbit Fur
Glass
Human hair
Nylon
Wool
Fur
Lead
Silk
 When the motor is turned on, the lower roller (charger)
begins turning the belt. Since the belt is made of rubber and
the lower roller is covered in silicon tape, the lower roller
begins to build a negative charge and the belt builds a positive
charge.You can understand why this charge imbalance occurs
by looking at the triboelectric series: Silicon is more negative
than rubber; therefore, the lower roller is capturing electrons
from the belt as it passes over the roller.
Do Now:
What do all magnets have in
common?
1. With your elbow buddy, use the bar magnet and the
horseshoe magnet. Take turns with others at your table.
2. See if you can make a paper clip stick to different parts of
each magnet.
3. Draw a diagram in your journal showing the number and
location of paper clips on each magnet.
Magnetism
 Magnets have 2 poles, North and South
 Opposite poles (North and South) attract
 Like poles (South and South) (North and North)
repel
 The area around a magnet where the force is
strongest is called the magnetic field.
Electricity
• Electricity is a flow of electrons
•An electric circuit is a pathway
that allows the flow of electrons.
•An electric circuit has 3 parts:
1. Power/Energy source
2. Switch
3. Resistor - Objects that require an
electrical current to work (ex. light bulbs,
fan, bell).
Open and Closed Circuits
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An open circuit does not
allow the flow of electricity
(lights turned off)
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A closed circuit allows the
flow of electricity (lights
turned on).
1. Draw an open circuit with 6 resistors.
2. Draw a closed circuit with 4 resistors and
2 power sources.
3. Draw a closed circuit with 5 resistors.
2 Types of Circuits
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Series circuits (Christmas
lights) are all wired together to
the power source. If one bulb
goes out, they all go out.
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Parallel circuits (store signs)
are wired separately to the
power source. If one bulb
goes out, the others stay on.
Conductors
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Metals are good conductors of
electricity (wires)
They CONDUCT electricity
Plastic is a poor conductor, or insulator,
of electricity (cover the wires).
INSULATORS do not conduct electricity
BBC website http://www.bbc.co.uk/schools/scienceclips/ages/8_9/circuits_conductors_whatnext.shtml