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8th gde Electricity

The basic building blocks of matter Atoms
What are the three particles found in atoms? Protons (+), neutrons (0), and electrons(-)
Which particles are found in the nucleus? Protons and neutrons
Where are electrons found? In the “electron cloud” outside the nucleus
Which is the only particle that moves freely? Electrons, because they can be “knocked off” the outside of the atom, creating an electric charge.
What causes an object to become negatively charged? Electrons move from another object to that object
What causes an object to become positively charged? Electrons move to another object from that object
A charged object is brought near another object or surface, producing an electric charge Charging by induction
Two objects are brought into contact (rubbing/friction), and negative charges move from one to the other, giving both a charge Charging by conduction
Electric charges that are the same do this Repel
Electric charges that are different do this Attract
What are the two types of electricity? Static and current.
The build up of charges in one area due to the gain or loss of electrons when objects rub together is called this Static Electricity
What causes a spark (electric discharge) to “jump?” The negative charges built up on one object (usually by conduction) are attracted to a conductor with a lower concentration of negative charges.
The flow of electrons in a wire electric current
How do electrons behave in current electricity? They “flow” through a conductor from an area of negative charge to an area of positive charge.
Materials like metals that allow electrons to flow easily through them conductors
Materials that resist the flow of electrons insulators
Name some conductors Most metals, water, the human body
Name some insulators Plastic, wood, glass, rubber
What example of electric current did we study? A lit flashlight
What source of electric current did we build in lab? a dry cell
What do we call a large discharge of static electricity from cloud to cloud or cloud to ground? Lightning
What happens to clouds in a thunderstorm? Circulating winds cause a build up of negative charges near the bottom of the cloud by conduction (rubbing of molecules/atoms within the cloud)
What happens to the ground and objects on the ground in a thunderstorm? As charged clouds draw closer, negative charges move away from them, giving the surface of the ground/objects a positive charge (charging by induction)
What is lightning? A large discharge of static electricity from cloud to cloud or cloud to ground caused when negative charges “jump the gap” to a positively charged area.
What do we call it when static electricity or other unwanted charges are directed into the earth through a conductor? Grounding
What causes thunder? The superheating of air during a electric discharge (lightning) causes it to rapidly expand, producing sound waves (thunder).
What is the SI unit for measuring current? Amps
A closed loop that electric current flows through is a ______ circuit
A circuit with only one path (loop) for current to flow through is a ________. Series circuit
A circuit with more than one path for current to flow through (each device has its own path) is called a _____. Parallel circuit
What is one example of a series circuit? Older Christmas lights (when one bulb goes out, the whole string won't light)
How are most houses wired today? They are wired in parallel.
Name some household safety devices. Fuses, circuit breakers, grounded outlets, GFCI outlets
What does a closed circuit require for current to flow? A Voltage difference
The difference in potential electric energy, or charge, between two areas that creates the push to move charges in a circuit. voltage
In SI, what is the unit for Voltage? Volt
This produces a voltage difference when a chemical reaction makes the carbon suspension rod positive, and the zinc container negative Dry Cell
The voltage difference in this is created by a chemical reaction in an electrolyte solution Wet Cell
What creates the voltage difference found in wall outlets? The generator at a power plant provides the "push" that we use to run electric appliances
Opposition to the flow of current in a circuit is called ______. Resistance
What is the SI unit for resistance? Ohms. (The ohm symbol resembles an upside-down horseshoe)
What does resistance tend to produce? Heat and/or light
What are the three parts of a circuit? 1) a voltage source, 2) a path for current 3) a device that uses light and provides resistance
What is the difference between AC & DC? DC (direct current) flows in one direction; AC (alternating current) switches directions many times per sec.
What have we studied that uses direct current? A flashlight (powered by a battery or solar cell)
What type of current is found in our homes? Alternating current
Created by: judi829