Transcript Electricity - Barren County Schools

THURSDAY DO NOW
• What is electricity?
• Why is it important for you to learn about
electricity?
• Today’s PLAN
– 1.1 Describe properties of electric and magnetic
(electromagnetic) forces as being attractive or repulsive.
– 1.2 Explain how electric and magnetic force size depends
on magnitudes of the charges, currents, or magnetic
strengths involved and on the distance between the objects.
– 1.3 Differentiate between charges, current, electrical field,
and magnetic field.
• Todays DO
– We will complete the Magnetism Explore Activity. (4th period
only)
– We will complete guided notes over Electricity.
– We will get graded papers/quizzes back and talk about our
grades and how to make up work.
FRIDAY DO NOW
• Begin completing your Analyzing Data Mid-Year
Learning Check. (You will have about 10-15
minutes to finish this quiz.)
• Do not write on the quiz. Answer the questions
on your scantron.
• Do your own work.
• Do your best.
• When finished, turn over your scantron and
make a list of the questions you felt confident
about and the ones you were unsure about. For
those you are unsure about, tell what specifically
confused you.
• Today’s PLAN
– 1.1 Describe properties of electric and magnetic
(electromagnetic) forces as being attractive or repulsive.
– 1.2 Explain how electric and magnetic force size depends
on magnitudes of the charges, currents, or magnetic
strengths involved and on the distance between the objects.
– 1.3 Differentiate between charges, current, electrical field,
and magnetic field.
• Todays DO
– We will complete our Analyzing Data Mid-Year Learning
Check
– We will complete guided notes over Electricity and Circuits.
– We will complete a foldable about Electric circuits to use
next week during a lab.
Electricity
Thinking back…
• All matter is made
up of ______________.
• The two types of subatomic particles that
have a charge are
_______________ and
______________.
• Protons - _____
charge
• Electrons - _____
charge
protons
electrons
Electricity comes
from the movement
or placement of
these charged
particles.
Think about a magnet…
• What happens when you
try to touch the two north
ends together?
– They repel each other
• What happens when you
try to touch the two south
ends together?
– They repel each other
• What happens when you
try to touch the north
and south ends
together?
– They attract each other
The same applies to
ELECTRIC CHARGES
• Charges that are the same, repel
each other.
• Charges that are different, attract
each other.
Two Protons
Two Electrons
Proton & Electron
What’s going to happen?
+
+
-
-
+
-
The charges of protons and
electrons cause the object they
make up to be positively or
negatively charged.
+
+
+
+
+ -
+
-+
-
- +
+ - +
+
-
+ +
+
+
-
+
-
+
+ -
• Most objects
normally have
no overall
charge.
– This is because
each atom has
an equal
number of
protons and
electrons.
However, an object can
become charged by gaining or
losing electrons.
• When an object
loses electrons, it will
have a
_____________
charge.
• When an object
gains electrons, it will
have a
_____________
charge.
-
+
-
-
+
+
-
-
+
-
+
+
-
+
-
+
- -
That’s Static Electricity!
• The build-up of
electric charges
• Static means “not
moving” or “not
changing”
– In static electricity,
charges build up
on an object, but
they do not flow
continuously.
• Number your group members 1-4.
• Student 1: Blow up and tie off a balloon. Then
tie a string around the balloon’s knot.
• Student 2: Blow up another balloon and tie it
off.
• Student 3: Hold the end of the string allowing
the balloon to dangle.
• Student 4: Rub the balloon without the string
on your hair. (This gives the balloon a negative
charge – electrons move from your hair to the
balloon)
• Student 1: Rub the balloon with the string on
your hair.
• Student 4: Slowly move your balloon toward
the hanging balloon. What happens?
• Student 2: Rub the hanging balloon with a
dryer sheet. What does this do to the balloon’s
charge?
• Student 1: Rub the balloon with the string on
your hair.
• Student 4: Slowly move your balloon toward
the hanging balloon. What happens?
MiniLab
How can an object
become charged?
• Three ways to move electrons from one
object to another:
– Friction - rubbing
– Conduction - touch
– Induction – movement of electrons within an
object
Static Discharge
• When a negatively
charged object and
a positively charged
object are brought
together, electrons
transfer until both
objects have the
same charge.
• Static discharge is the
loss of static
electricity as electric
charges transfer from
one object to
another.
Often, a static
discharge
produces a
spark.
•Lightning is
another
example of
static
discharge.
Conductors
• Conductors allow electricity to pass
through them easily.
• Example: metals (such as those inside of
wires- copper)
Insulators
• Insulators do not allow electricity to pass
through easily.
• Example: plastic, rubber (such as that on
the outside of a wire)
Circuits
• A circuit is a pathway along which an
electric current can travel to a device.
• There are two different types of circuits:
1. Series
2. Parallel
Series Circuit
• A series circuit has only ONE pathway for
electricity to flow.
• All devices are located along this single
pathway.
• Any break in the circuit (such as a open
switch) will stop the flow of electricity and
the device(s) will no longer work.
• Example: old type of Christmas tree
lights.
Series Circuit
Light bulb symbol
Battery symbol
Switch symbol
Parallel Circuit
• A parallel circuit has MULTIPLE paths
along which electricity can travel.
• If one pathway is broken, the others can
still carry electricity.
• Example: household circuits, newer
Christmas tree lights
Parallel Circuit
Series and Parallel Circuits
Electromagnets
• An electromagnet is a temporary magnet
made by passing an electric current
through a wire coiled around a metal core
(such as an iron nail).
• Electromagnets have two advantages over
normal magnets:
1. They can be turned on and off.
2. Their strength can be changed based upon
the amount of current flowing through it.
Electromagnets
• The amount of current flowing through an
electromagnet can be changed by:
1. Changing the number of batteries used
(more batteries = stronger electromagnet)
2. Changing the number of wire coils (more
coils = stronger electromagnet)
Electromagnets