Warm Up – copy the objective Have you ever felt a shock when you touched someone or something? Describe your experience.

The charged particles in atoms are the protons(+) and electrons (-). Electrons can be gained or lost. If an atom has more protons than electrons it is positive, if it has more electrons it is negative.

Law of Electric Charges Like charges repel Unlike charges attract Sketch the balloon demonstration, add in the charges. Electric field- region where electric force is exerted on other objects

Static electricity is the buildup of charges on an object electrons are transferred by: friction conduction induction polarization

Static discharge – the loss of static electricity as electric charges transfer from one object to another Examples:

electroscope Used to detect electrical charge Operates through charging by induction If the foil leaves move apart, a charge is present(+ or -)

minilabs Fold a piece of notebook paper into 8 boxes Number the boxes 1-8 Answer the questions on the green cards in complete sentences

Current electricity- Continuous flow of electric charges through a material Conductor- material that transfers electric current because it has loosely bound electrons ex. Copper

Insulator- material that does not transfer electric current- electrons do not move freely among its atoms Ex. wood, plastic, glass, rubber Semiconductor- materials that allows some current to pass but not all ex. Silicon Used in computer chips

Why is the copper wire a conductor but the rubber on the outside considered an insulator?

Current needs a closed path called a circuit. Electrons travel from negative to positive. Is this circuit open or closed? Would the light bulb light? Circuits contain a battery, wires, and a resistor like a light bulb or motor that resists and uses the current.

Would This Work?

Do not make short circuits- they will burn you!

How could you test if materials are insulators or conductors? Make a circuit tester like the one below.

Minilab Let’s try to light a light bulb, see what materials make good conductors and practice the vocabulary. Complete cards Answer questions in complete sentences.

What affects current flow? Voltage and resistance affect current flow. Voltage – difference in electrical potential ex. 1.5 V battery has less voltage than a 9V Resistance- a measure of how difficult it is for charges to flow through an object

Voltage from the battery is the push of electrons. Current is the flow of electrons. Resistance is the slowing of the current. So… with the same voltage

Resistance in a wire is affected by the diameter, length, material and temperature of the wire. Thick, short, cold and copper wires allow more current to flow through them.

Ohm’s Law I = V / R V=I x R Georg Simon Ohm ( ) I= Current (Amperes) (amps) V= Voltage (Volts) R= Resistance (ohms)

I= Current (Amperes) (amps) V= Voltage (Volts) R= Resistance (ohms) Unit review

Minilab Let’s practice the vocabulary and then try to build some simple circuits. Complete red cards Answer questions in complete sentences

Series circuit- one path for electricity to follow Advantage – easy to wire Disadvantage- if one light goes out they all go out and bulbs get dimmer as you add more bulbs

Parallel circuit- several paths for current to take Advantage – if one bulb goes out, the others remain lit, brightness of the bulbs does not change as you add more Disadvantage – complicated to build

Which type of circuit allows two or more paths for electrons to follow on their way back to the battery? Which type of circuit has only one path from the battery through the circuit and back to the battery? In which circuit will the bulbs be brighter?

Minilab Let’s build 2 circuits and then answer questions based on circuit diagrams. Complete yellow cards Answer questions in complete sentences

Practice the vocabulary for homework. Choose 1 of the following: Create a concept map using as many of the new vocabulary words as you can. Make flashcards of the new words. Make a matching review for the new vocabulary words.

Warm Up – Copy the objective Copy and fill in the Venn diagram below. You may use your notes. Static electricityCurrent electricity

Static electricityCurrent electricity

Magnets A magnet is a material that attracts iron and materials that contain iron. all of the atoms are facing the same direction

Magnetic pole – end of the magnet where the force is the strongest The lines indicate the magnetic field. More lines mean more force Unlike poles attract and like poles repel

Using your 2 magnets, demonstrate attraction and repulsion. How many paper clips can you pick up with a nail? Make a temporary magnet by rubbing a nail along a magnet in the same direction to align the atoms in the nail. How many paper clips can you pick up now?

Add the magnetic lines of force Magnets are strongest at the poles.

Earth has an iron core that acts like a giant magnet. Earth’s magnetic field aligns compass needles to point North.

We use the Earth’s magnetic field to find direction. The needle of a compass always points toward the magnetic south pole. We call this direction “North” (remember, opposites attract)

How are electric currents and magnetic fields related? Called electromagnetism

The magnetic field made by current electricity can be turned on and off, can reverse direction and have its strength changed by changing the core material current intensity number of coils

Let’s experiment with how electricity and magnetism are related? Wrap wire 3 turns around a compass. Hook the free ends of the wire to the battery. What do you notice? What caused the compass needle to move?

Solenoid – coil of wire with a current running through it Electromagnet- solenoid with an iron core What do you think are some ways to increase the strength of an electromagnet?

A motor transforms electrical energy into mechanical energy. How do you think this motor works?

An electric current is induced in a conductor when the conductor moves through a magnetic field. Generators changes mechanical energy into electrical energy. Examine the homemade generator. How do you think it works? What do you have to do to make the light turn on?

Fill in the blank with generators or motors? ______ change electrical energy into mechanical energy. ________ converts mechanical energy into electrical energy. Most of the electrical energy we use comes from _____________. Examples of __________ include blenders and washing machines.

The wire changes direction repeatedly so the current produced changes direction- alternating current Direct current- a current with charges that flow in one direction 2 types of current electricity- AC/DC

How are alternating and direct current different? How is each produced and an example of each?

The diode is a semiconductor device that acts like a one way valve to control the flow of electricity in circuits. Solar cells are made of diodes that produce DC when light strikes them. LEDs emit visible light when current passes through them.

46 New traffic lights

Transistors are semiconductor devices used to amplify electrical signals or to turn electricity on/off.