Hey, hey, hey! Today is Monday and that means DNews. It also means our test is merely days away. Remember, you may use one small note card, front and back, for the test.
DNews here and study materials below...
Below is a picture of Ohm's Law, which we will begin covering today, and the study guide.
Remember:
V=Voltage (Volts)
I=Current (Amps)
R=Resistance (Ohms)
DNews here and study materials below...
Below is a picture of Ohm's Law, which we will begin covering today, and the study guide.
Remember:
V=Voltage (Volts)
I=Current (Amps)
R=Resistance (Ohms)
Electricity and
Magnetism Study Outline
·
I know the parts of an atom.
o
Protons (positive charge) and neutrons (no
charge) in the center.
o
Electrons (negative charge) on the outside.
·
I know what electricity is and how it relates to
the parts of an atom.
o
Electricity is the flow of electrons.
o
Electrons are the parts of an atom that move
because they are on the outside of the atoms, where they already move freely.
·
I know the difference between static electricity
and current electricity.
o
Static electricity is the sudden discharge of
electrons when they come in contact with an opposite charge or another
conductor.
o
Current electricity is the constant flow of
electrons through a circuit.
·
I know how static electricity and current
electricity are formed.
o
Current electricity requires a power source,
whether it is a battery, turbine, or something else that creates a charge.
Current electricity allows electrons to flow through conductive wires, in a
closed circuit, to power a variety of different things.
o
Static electricity is created when electrons
build up in one area- usually from friction (rubbing one surface against
another) and adhesion (electrons sticking from one surface to another).
·
I know the difference between conductors and
insulators.
o
Conductors-allows electricity to flow freely.
(Ex. Metals)
o
Insulators-prevent the flow electricity. (Ex.
Rubber, Plastic)
·
I know what voltage, current, and resistance are
and how they are measured and related.
o
Voltage is the electric force that causes the
free electrons to move from one atom to another. Just like water needs pressure
to force it through a hose, electrical current needs some force to make it
flow. A volt is the measure of electric pressure. Voltage is usually supplied
by a battery or a generator. The symbol for volts is “V.”
o
Current is electricity in motion. It
measures the amount of electrons that can flow through a material like a
conductor. Electrical current is measured in amperes or "amps"
for short. Amperes is like the amount of water flowing through a hose in a
certain amount of time or the amount of electricity flowing through a wire. The
scientific symbol for amps is the letter "I".
o
Resistance controls how much current is allows to flow through the circuit. It can
be like a kink in the hose that stops or slows down the flow of water.
Resistance is measured in “ohms” and is written as “R.”
o
When I increase the resistance, I decrease the
current. When increase the voltage, I increase current.
·
I know how to use Ohm’s Law to find voltage,
current, and resistance.
o
V=I x R
o
R= V/I
o
I = V/R
·
I know how to find the resistance level of a
resistor (hint: colored bands).
o
The first color band tells you the first number
of resistance. The second colored band tells you the second number. The third
colored band tells you the number of zeroes after the first two numbers.
·
I know how to identify the different electrical
symbols in a schematic diagram.
o
See attached sheet.
·
I know the difference between a series and
parallel circuit.
o
In a series circuit, the same current flows
through all the components. They are in one continuous loop. An example of a
series circuit is a string of Christmas lights. If any one of the bulbs is
missing or burned out, no current will flow and none of the lights will go on.
Parallel circuits are like the smaller blood vessels that branch off from
an artery and then connect to a vein to return blood to the heart. Now think of
two wires, each representing an artery and a vein, with some smaller wires
connected between them. These smaller wires will have the same voltage applied
to them, but different amounts of current flowing through them depending on the
resistance of the individual wires.
An example of a parallel circuit is the wiring system of a house. A
single electric power source supplies all the lights and appliances with the
same voltage. If one of the lights burns out, current can still flow through
the rest of the lights and appliances. However, if there is a short circuit,
the voltage drops to almost zero, and the entire system goes down. Below there
is a series circuit on the left and a parallel on the right.
·
I know the difference between direct current and
alternating current.
o
With direct current, the current is always
flowing in the same direction; batteries are an excellent example of a source
of direct current.
o
With alternating current, the current is
constantly changing direction.
·
I know the two famous scientists who designed
these two types of current the late 19th and early 20th
centuries. (Tesla and Edison
·
I know how electromagnetism works.
o
Electromagnetism is using an electric circuit to
create a magnetic field. The stronger the current, the stronger the field. You
can also increase the strength by adding a solenoid, which is a wire coiled
around an iron core.
·
I know how magnets work.
o
Magnets are items that use a magnetic field (an
invisible force) to attract objects. This magnetic field is created when
magnetic domains are aligned from a north pole to a south pole in magnetized
objects. Just like with electricity, opposites attract. Like poles, just as
like charges, will repel, and opposite poles, like opposite charges, will
attract. Most magnets contain magnetite, which is a naturally occurring type of
iron ore. However, magnets can also be made from aluminum, nickel, and cobalt.
·
I know why the earth is like a magnet.
o
The inside of the earth is theorized to have
large deposits iron materials, which add to its magnetic properties. These
magnetic properties create align to create a magnetic north and south pole,
which then creates a magnetic field around the earth.
·
I know that opposite forces attract and like
forces repel in both magnetism and electricity.
·
I know the types of objects can be magnetized or
attracted to magnets, which are not, and why.
