Statics, Coulomb Law, and current electricity.Friday, February 12, 2016

Friday, 2/12

How are the forces of gravity and the forces that keep the planets rotating around the sun similar? How are they different?

Upcoming dates: Friday, 2/12 – Statics quiz – moved to Wednesday, 2/17 Wednesday, 2/17 – Series circuit quiz – moved to Friday, 2/19 Friday, 2/19 – Parallel circuit quiz – moved to Tuesday, 2/23 Tuesday, 2/23 – Circuit design due Thursday, 2/25 – Unit quiz Monday, 2/29 – Electricity Test and missing work deadline Friday, 3/4 – Magnetism quiz Friday, 3/4 – 3NWS Extra credit due by 4:00 PM Thursday, 3/10 – Waves Quiz Friday, 3/11 – End of the 3NWS

Thursday, 2/11

Use your video notes to complete the following sentences about static electricity:1. Static electricity is also know as electricity at

rest2. Static electricity produces electric charges that

can be confined to an object.

Induction/Conduction guiding questions (6 minutes) What circumstances must be present for

conduction to take place? What type of charge is transferred during the

process of conduction? Draw the diagram that demonstrates conduction. What circumstances must be present for

induction to take place? What type of charge is transferred during the

process of induction? Draw the diagram that demonstrates induction.

Coulomb’s Law guiding questions (6 minutes Explain the affect the value of the charges and

and the distance of the charges has on the electrical force.

Write Coulomb’s equation and label the variables (include units).

How do you convert micro coulomb’s (μC) to coulombs

What does the value of Felectric tell you about the charges attraction/repulsion?

Set up the G and U for example #1.

Practice

Article – Shocking idea Number your paragraphs (there should be 8). Highlight the following words:

Electricity (all versions such as electric) Shock Charge Static Positive Negative Neutral Friction

Circle words you don’t know the meaning of. Underline statements about static electricity.

Electric Current The continuous flow of electrons

through a conducting metal.

Alternating Current Flow of current that periodically changes

direction Produced in power plants

Current from a wall outlet changes direction 120 times per second

Direct Current The flow of current in one consistent

direction Examples

Batteries Solar cells

Current from a battery travels from the positive terminal to the negative terminal.

Common Language

Note Taking GuideQuantity Symbol Definition Unit Measuring Device

voltagecurrent

resistance

Voltage Voltage (V) (also know as Potential Difference)

can be thought of as the force pushing electric charges along a conductor. Voltage between two points creates an electric field. Measured in Volts (V)

Voltmetera device that measures

electric potential difference, must be connected in parallel

Current Electric current (I) is the movement of

electric charge in a conductor. Measured in Amps (A)

Ammetera device that measures current

attached in series

Resistance Resistance (R) is a measure of how

difficult it is to push the charges along. The energy is transformed at the

resistor (potential energy is converted). Examples: light bulb, charging your

phone, making coffee, etc. Measured in Ohms ()

Note Taking GuideQuantity Symbol Definition Unit Measuring Device

voltage V Energy in the circuit

Volts Voltmeter

current I Rate of flow Amps Ammeterresistance R Opposes current OhmsΩ Ohmmeter

Ohm’s Law Ohm's Law analyzes the relationship

between voltage and current in an ideal conductor.

Ohm's Law is given by:

V = I * R

ExampleA flashlight that is powered by 3 volts and uses a bulb with a resistance of 60 ohms. What is the current flowing through the circuit?

Practice

Electrical Circuit Terminology Circuit – a path that allows electricity to

flow Circuit diagram – a simplified

representation of an electrical circuit that shows only the electrical connections of elements in a circuit.

We will study two types of circuits: Series circuit Parallel circuit

Cool Down What is the difference between static

and current electricity?

Resistors can be connected in series; that is, the current flows through them one after another.

Series Circuits

Kirchhoff’s RulesLoop Rule: The sum of the potential differences (voltage) around any closed circuit loop is zero.

Kirchhoff’s RulesLoop Rule: The sum of the potential differences (voltage) around any closed circuit loop is zero.

Series Circuit1. total resistance is the sum of the separate resistors

RT = R1 + R2 + R3 + ...2. current is the same through each resistor

IT = I1 = I2 = I3 = ...3. total potential difference is the sum of each

VT = V1 + V2 + V3 + ...In other words, in a series circuit,

resistance and voltage add,but current stays the same.

Series Circuit Example