Ohms Law

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Ohms Law

• Created by Mr. Elmy
• For his students.
• Modified by Mrs. Dever
• For her students

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Conductor

• A conductor is a material that current can pass
  through easily, like metals.

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Insulator

• An insulator is a material that current cannot
  pass through easily, like plastic.

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Resistor

• A resistor is a material that resists, but
  doesnt stop the flow of current.

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Resistance Opposition to the flow of electrons.
It changes electrical energy into thermal energy
and/or light. Measured in ohms. Conductors
have less resistance than insulators.
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Wire resistance greater for 1)
Longer wires 2) Thinner wires
3) Higher temperatures
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• Electrical Resistance.
• This is when current flow is slowed down.
• Current seems to lose energy. Actually, the
  electrical energy is converted into heat and/or
  light.
• The symbol is R.
• The unit is the ohm (?).

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Water Heater Element
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Light bulb
Stove Top Burners
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Flowing charge is called current. The symbol is I
and the unit is the ampere or amp (A).
SIM
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For your notes Electric Current 1. The reason
electric charge flows from one place to another
is voltage.
a. Voltage is the difference in electrical
potential between two places where electrons are
flowing. b. Voltage is the push that makes
electric charges move. c. Measured in volts
(V).
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2. The flow of electric charge is called
current. a. Current is measured in amperes,
or amps (A). b. Voltage causes current. 3.
The amount of electric charge is measured in
coulombs. a. 1 coulomb is the charge carried
by 6.24 x 1018 electrons. b. 1 amp is 1
coulomb per sec.
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6. Ohms law Voltage Current Resistance
V I R
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Connecting Ohms Law to the Water Lab

• When the resistance was the same, how did
  squeezing the baster harder (more voltage) affect
  the current (amount of water flowing out of the
  tube)?

V I R
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Connecting Ohms Law to the Water Lab

• When the resistance went up (you clamped the
  tube) how did the current change if you squeezed
  with the same force (voltage was the same)?

V I R
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Connecting Ohms Law to the Water Lab

• Suppose you clamped the tube (increased the
  resistance) AND you wanted more water to come out
  of the tube (increase current), what would you
  need to do to the voltage?

V I R
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Movie to help!
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Sources

• Bloomfield, How Things Work.
• Krauskopf Beiser, The Physical Universe. 10th
  ed.
• Tillery, Physical Science.