what are the three parts in a atom and where are they located
electrons- (negative charge) and circle around the atom
neutrons- (neutral) stay in the nucleus
protons-(positive charge) stay in the nucleus
How is electricity created
caused by the movement of electrons from one atom to another
conductors
conductors- materials that allow charges to move freely
good constructors have little resistance (gold, copper) bad have high resistance (cotton paper)
semi conductors
semi- higher conductivity than insinuators but lower than metals
super conductors
Materials that offer little to no resistance to the flow of electrons (activated in very cold temperatures)
insulators
materials that don’t allow charges to move freely or through them (plastic)
electric discharge
either electrons leaving or entering an object to make up or balance electrons
static vs current electricity
static- made by running together two or more objects making friction
example: static from a dryer
current- the flow of electric charge across an electrical field example: fridge
the 4 basic elements
1 source- the source of electric energy
2 conductor-the wire through which current flows
3 load- the items in the circuit that convert electricity into other forms of energy (bulb)
4 control- a switch or device that can turn on or off the circuit or devices along it, on or off
what is current (I)
charge
the amount of charge that passes a point in a conducting wire every second
-measured in amperes (A or mA)
galvanometer used to measure weak current ammeter for stronger currents
voltage (V)
potential difference
the difference in energy between one point in a circuit to another, its the push that makes electrons move
measured in volts with a voltage meter
what is resistance
slows down the movement of electric charge and converts electrical energy to other forms, as temperature increases so does resistance
series circuit
-only one current pathway, all moving charges travel through each component in the circuit (make higher voltage)
-easy to make, one break causes the whole circuit to stop
parallel circuit
-several different pathways, each load has its own current pathway, if there is a break in the circuit the other loads can still continue, used in homes
- more complicated and expensive
what is the difference between a positively charged object and a negatively charged object
postiviley- the object has more protrons, unblancing the charge
negtivley- the object has more more electrons unbalncing the charge
what is the law of charges
like charges repel
unlike attract
explain how an object can become charged
an object can become electricly charged when it gains or loses elecrtons the charge on an object depends on the balnce between postitve and negative charges
what are three ways to reduce resistance in a circuit
decrease tempertaure
increase diameter
dreacease the length of the wire
ohmic resistors
have constant resistance even when the current or votage changes the resistance stays the smae
variable resistors
do not have fixed resistance their resistance can be adjusted to control the amount of current in a circuit
ex- rheostats, thermistors and varistors
what is the difference between a battery and cell
a battery is made up of multiple cells, the more cells the more power in the battery
thermocouple
-heat to energy
device that converts heat into a small amount of electrical energy often used in temperature sensors
photovoltaic cell
-light to energy
a semi conducting material mostly silicon absorbing light and breaking the electrons to move freely then the current flows to a metal conductors (calculators)
the piezoelectric affect reversed
motion to electricity
the build up of voltage or a crystal being compressed on the opposite side of the the crystal conductor (BBQ lighter)
