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24 terms

8th grade science electricity

STUDY
PLAY
Electricity
The interaction between electric charges. THE MOVEMENT OF ELECTRONS CAUSED BY UNEQUAL AMOUNTS OF PROTONS AND ELECTRONS. THE MOVEMENT OF ELECTRONS.
Static electricity
*A buildup of charges on an object
*Can be done by running and transferring protons or electrons to another object and creating a charge.
*Build up of charges, discharges, and releases electrons
*Discharges can be small
*Example is static cling--built up charges have a charge and cling to other objects
Static discharge
The loss of static electricity as electric charges transfer from one object to another
Electric circuit
A complete, unbroken path through which electric charges can flow
Voltage
*The difference in electric potential energy between two places in a circuit
*Amount of force to push or move an electric current
*Measured in volt (V)
*Voltage source-a device to push an electric source
Electric current
*The continuous flow of electric charges through a material
*Rate which charges pass through a given point
*Takes path of least resistance, measured in Amps
*Example is an electrical device
Ohm's Law
*The law that states that resistance is equal to voltage divided by current
*Resistance=voltage (v)/current (amps or A)
**Increased voltage does not affect the resistance because if you double voltage, the current will double
Resistance
*The measurement of how difficult it is for charges to flow through a material
*The greater resistance, the less current
*Measured in Ohm
Series circuit
*An electric charge with a single path-only one path for current to travel
*Any break causes bulb to go out
*Resistance increases
Parallel circuit
*An electrical circuit with multiple paths-has more than one path for current to travel
*If breaks doesn't mean won't work
*Resistance decreases
Conductor
*A material where charges can easily flow
*Contain loosely bonded electrons that carry the charge and create an electric charge
Amp
*The unit for the rate of current.
*The number of amps describes the amount of charge flowing past a given point each second
Direct current
*Current consisting of charges that flow in only one direction in a circuit
*Known as DC current
*Examples are battery and motor
Alternating current
*Current that can flow in both directions
*Current consisting of charges that move back and forth in a current
*Known as AC
Example of static electricity
Balloon and hair
Example of static discharge
lightning
Examples of conductor
metals, water, acid
Insulator
*Material where charges cannot easily flow
*Electrons bound tightly to atoms and do not move easily
*Used to stop the flow of charges
Examples of insulators
rubber, glass, sand, plastic, wood
equation for voltage
voltage=current*resistance
Units used for resistance
Ohms
Ways to get an electric charge
1)Friction--the transfer of charge from one object to another by rubbing; electrons move from one object to another when rubbing
2)Conduction-The transfer of charge when electrons move from a charged object to another object by direct contact; objects touch another and electrons transfer; electrons transfer to the positive charged object
3)Induction-The transfer of electrons from one part of an object to another part, caused by the electric field of another object, without the two objects touching; electric field attracts or repels electrons
Example of voltage source
Battery, generator
Factors that determine resistance
1) Composition of Material used
Insulators-don't let electrons flow. Higher reistance so charges don't move easily so less current
Conductors-electrons flow. Lower resistance so charges move easily so more current
2) Length of Materials
Longer-more resistance so less current
Shorter-less resistance so more current
3) Diameter-
Thinner-more resistance so less current
Thicker-less resistance so more current
4)Temperature
Hotter or higher temp-more resistance so less current
Cooler or lower temperature-less resistance so more current