22 terms

Electricity and Magnetism, Science - Grade 4

MSD - Ms. Bassing - Science Scott Foresman Grade 4, Chapter 13 Electricity and Magnetism
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Terms in this set (...)

electric charges
tiny particles that carry units of electricity; can be positive (+) or negative (-)
electrically neutral
matter that has the same number of positive and negative charges
negatively charged (-)
matter that has more negative than positive charges
positively charged (+)
matter that has more positive charges than negative charges
repel
push away from each other
*LIKE charges push away from each other
attract
pull toward each other
*UNLIKE charges pull toward each other
static electricity
electric charge that BUILDS UP on a material; static discharge may cause a small shock
*rubbing a balloon with wool causes this
electric current
CONTINUOUS FLOW of electric charges
conductors
materials that negatively charged particles CAN MOVE THROUGH EASILY
Examples: tap water (best), some metals, living things
insulators
materials that electric charges DO NOT FLOW THROUGH EASILY
Examples: plastic, rubber, wood
electric circuit
pathway that an electric current follows that
must have at least 3 parts:
1) power source, or battery
2) conductor, or wire
3) object that uses current, or bulb
incomplete circuit
when there is a gap or opening in a circuit
*If one of the parts of a circuit (battery, wire, bulb) is removed, electric current cannot complete the path.
series circuit
circuit in which the parts are connected so that the electric current passes through each part along a SINGLE pathway
parallel circuit
circuit in which the parts are connected so that the electric current passes along MORE THAN ONE pathway
switch
used to make it easier to turn a circuit off and on
electric cell
object that changes chemical energy into electrical energy (battery)
magnet
object that attracts SOME metals (all metals are not magnetic); mainly attracts iron
*bar magnets cannot be turned on and off
magnetic poles
two areas on a magnet with the greatest magnetic force (north pole and south pole)
*unlike poles of two magnets ATTRACT each other and like poles of two magnets REPEL each other
electromagnets
strong temporary magnets that use electricity to produce magnetism; can be turned on and off; scientists and engineers work with these
Examples: blenders, computer disk drives, doorbells
*Must have 3 parts:
1) something to produce current, such as a battery
2) a wire
3) an iron core to wrap the wire around, such as a nail
generator
device that uses magnetism to convert energy of motion into electrical energy
*changes motion into electricity
motor
device that changes electrical energy into energy of motion
*changes electricity into motion
safety with electrical circuits
1) always avoid skin contact with materials
2) do not leave a battery attached to a wire for more than a short period (wire will get very hot)