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Electricity & Magnetism SOL: PS11, 6.4. I. Electricity. Def - movement of electric Charges (electrons). B. Charges - force caused by an unequal number of protons and electrons. Electrons - Negative Charge Proton - Positive Charge. Electricity. I. Electricity cont.
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I. Electricity • Def - movement of electric Charges (electrons). B. Charges - force caused by an unequal number of protons and electrons. • Electrons - Negative Charge • Proton - Positive Charge
I. Electricity cont. • Golden Rule of Physical Science OPPOSITES ATTRACT <=> LIKES REPEL • Repel - two positives or two negatives • Attract - positive and a negative C. Electric Field - area where electricity can exert it’s force.
II. Static Electricity • Def - buildup of electric charges on an object. B. Ways to create static Electricity? • Friction - rubbing two objects together • Conduction - making direct contact with a charged object. • Induction - bringing it close to a charged object.
II. Static Electricity Cont. • Electroscope - Device that determines if an object has a charge. • Lightning - Largest and most powerful form of static electricity.
III. Conductors & Insulators • Conductors: • Def - material that allows electricity to move through it. • Ex. - most metals, water, acid • Gold is the best conductor, copper is the most common conductor. • Insulators: • Def - material that prevents electricity to pass through it. • Ex. - rubber, plastic, wood, glass SmartBoard Balloons 1st Sheet
IV. Electric Current • Current • Def - Flow of the electricity • Units: Amps • Voltage • Def - Push of the current • Units: Volts • Sources of Current • Electrochemical Cell (Battery) • Wet Cell - battery that contains water and acid (Car Battery) • Dry Cell - battery that contains acid and base (flashlight battery)
IV. Electric Current Cont. • Types of Current • Direct (DC) - travels in only one direction (Battery) • Alternating (AC) - travels back and forth (House) • Galvanometer - measures the direction and strength of a current. • Resistance • Def - any force that opposes a current Ex. - Wires, Light Bulbs 2. Units: Ohms
IV. Electric Current Cont. Resistance Cont. • How can you reduce Resistance • Short Wires - less time to travel • Thick Wires - more room to flow • Cold Wires - less heat to overcome • Ohm’s Law (Formula) Current = Voltage/Resistance; I=V/R
V. Circuits • Def - complete closed path for electricity to flow • Flows from “-” post to “+” post • Types of Circuits • Series - only one path • Parallel - two or more paths • Why is parallel circuit better? • In a series circuit, one break shuts the whole circuit off. • Parallel provides more voltage SmartBoard Circuit Building
Parallel & Series Circuits SmartBoard Balloons 2nd Sheet
Smartboard Circuits http://www.andythelwell.com/blobz/
VI. Power & Energy • Power • Formula: Power = Volts X Amps • Units: Watts • Energy • Formula: Energy = Watts/1000 X Hours • Units: Kilowatt Hours (kWh) • Reading an electric meter • Cost ($$) • Formula: Cost = kWh X Unit Cost
Energy Calculators • https://www.appalachianpower.com/CustomerService/HelpfulInformation/SavingEnergy/energyCalculator/ApplianceVA.asp • https://www.appalachianpower.com/CustomerService/HelpfulInformation/SavingEnergy/energyCalculator/LightCalcVA.asp • http://www.energyquest.ca.gov/vampires/dswmedia/index.html
VII. Electric Safety • Ground Wires • Function - pulls electricity towards the ground • Earth has a positive charge while electricity has a negative charge. • Circuit Breakers and Fuses • Function - prevent circuit overload and electric fires.
Chap. 8 Magnetism • Magnetism • Def - force between two metals with aligned domains • Domains - magnetized regions in some metals • Loadstone - first magnet discovered by the Greeks • Parts of a Magnet: • Poles - ends of the magnet • North and South Attract • North and North Repel; South and South Repel • Attraction is strongest at the poles
I. Magnetism D. Parts of a Magnet cont: 2. Magnetic Field - extends from pole to pole • Removing Magnetism • Drop it • Hit it • Heat it • Cutting a magnet? Makes 2 magnets
II. Earth as a Magnet • Earth has poles • Earth has a magnetic field • Solar Winds - deflected by the magnetic field • Auroras - solar particles trapped at the poles. • Also called the Northern Lights and Southern Lights • Earth’s poles attract and repel other magnets. 1. Ex. - Compass
III. Magnetism & Electricity • Electromagnet • Def - device that changes electricity into magnetism • Ex. - wire wrapped around a nail, attached to a battery. • What are two ways you can make an electromagnet stronger? • Wrap more coils of wire around the nail • Use a bigger nail • Uses - Electric Motor
Magnetism & Electricity Cont. • Generators • Def - device that changes magnetism into electricity • Uses - Hydroelectric plants • How are magnetism and electricity alike? • They can create each other • Both have fields • Both follow the same rule of attraction • Uses of Magnetism?