Science- Test on Friday
Terms in this set (40)
a build up of charges on a material, they do not "flow"
static electricity can be transferred in 3 ways~
friction(one will gain electons becoming negative and one will lose elsectrons becoming positive), conduction(touches another object and the charge is transferred), and induction(the movement of electrons because of the electric field around charged objects)
Static Electricity vs. Current
static electricity is a build up of charges on a material that do not flow and electric current is the number of electrons flowing pass a point in a set amount of time- flow continuously DIFFERENCE= CHARGES DO NOT FLOW IN STATIC ELECTRICITY WHILE THEY CONTINUOUSLY FLOW IN ELECTRIC CURRENT
There are two types of Current~
Alternating Current (AC) and Direct Current (DC)
Alternating Current (AC)
charges flow in one direction and then another (Europe)
Direct Current (DC)
all charges go in one direction (USA)
There are 4 factors that affect resistance~
material (insulators have more resistance than conductors), length (long wires have more resistance than short wires), diameter (thin wires have more resistance than thick wires), and temperature (hot wires have more resistance than cold wires)
Path of Least Resistance
if electric charge can flow through either of two paths, more of the charge will flow through the path with lower resistance
circuits are made of 3 parts~
VOLTAGE SOURCE (a source that creates a potential difference in an electric current... has a positive and negative terminal) WIRES and RESISTOR(S) (effects how well current flows, they do work) more resistance= less current
How does current run?
Current runs from positive to negative
with charges, _______ attract
sometimes circuits can also include these:
There are 2 main types of circuits~
Series and Parallel Circuits
-the loads are all connected in a circle
-only one path that electricity can flow through
-all of the loads share the same current, which means that there is less of it per load
-if you open this circuit anywhere, the loads on it will turn off
-energy for each resistor is uneven (the first resistor has the most)
-all of the loads have a separate path from the battery and back to the battery
-several paths that electricity can flow through
-loads do not share the same current so the loads will have more power
-if you open this circuit anywhere, the loads on it will stay on
-all resistors have the same energy
Which is better to light you house?
It is better to light your house with a parallel circuit because the loads do not share the same current, therefore more power.
the rate at which electrical energy is converted into another form of energy (such as light sound, thermal, kinetic)
what is the unit for power?
Watts (W) or kilowatts (kW)
What is the process of which one watt is produced?
when one amp of current flows through a circuit with a potential difference of one volt
What do companies use to figure out the cost of your electric bill?
they measure the number of kilowatt hours you use
What do batteries contain?
What are Electrochemical cells comprised of?
electrolytes and electrodes (make terminals, which connect in a circuit positive and negative)
electrolyte is wet ex. car battery
electrolyte is a paste ex. duracell
NOTICED that lead and brass touching a dead frog leg would make the leg move- thought it was just an animal thing
-CREATED first battery by layering zinc, salt water soaked paper, and silver (1800)
-thought it was a chemical reaction not just an animal thing
-lead+brass+salty frog fluid= chemical reaction
What is the kilowatt hours formula?
kWh= V x I x hours/ 1000 ( if watts are given replace V x I with that number... if kilowatts are given do not divide by 1000)
What is the power formula?
power= current x voltage OR P= I x V
What is the cost formula?
cost= price x (# of kWh used) (the price will be provided)
What is the voltage formula?
voltage= current x resistance OR V= I x R
What is the formula used to find resistance? (most of the time depends on problem)
resistance= voltage/current OR R=V/I
What is the formula used to find current? (most of the time depends on problem)
current= voltage/resistance OR I= V/R
How are voltage and current related?
Voltage is the force that moves the current through out the circuit. No voltage= No current
How are current and resistance related?
The more resistance there is the less current there is.
Which type of circuit would receive equal amounts of electricity?
What are the electric charges and what can happen between them?
Negative charge and Positive charge; opposites attract and the same repel eachother
What are the three different ways to make static electricity?
friction, conduction, and induction
How does friction make static electricity?
by rubbing two uncharged objects, and one of those objects will gain electrons (becoming negative) and the other object will lose electrons (becoming positive)
How does conduction make static electricity?
when one object touches another object and a charge is transferred
How does induction make static electricity?
from the movement of electrons because of the electric field around charged objects.