Static Electricity Flashcards
Law of Electrical Charges
Like charges repel
Opposite charges attract
A neutral object attracts both positively and negatively charged objects
What are protons?
positive charge and are located in the nucleus
what are neutrons?
a neutral charge and are located in the nucleus
what are electrons?
a negative charge and are located around the nucleus
what is electrical charge?
when an atom has an inbalance electrons and protons
how many electrons and neutrons are there in a POSITIVELY CHARGED object?
have FEWER ELECTRONS than protons
how many electrons and neutrons are there in a NEGATIVELY CHARGED object?
have MORE ELECTRONS than protons
how many electrons and neutrons are there in a NEUTRALLY CHARGED object?
have an EQUAL NUMBER of protons and electrons
What is static electricity?
Static electricity is an imbalance of electric charge on the surface of an object
when does static electricity accumulate?
Accumulates on an object to form an ELECTRICAL CHARGE
Is static electricity moving or not moving?
static electricity is STATIONARY
Does static electricity move through wires?
NO, static electricty DOES NOT move through wires
What are some examples of static electricity?
During thunderstorms - lighting
when emptying out the dryer - static cling
When different materials are rubbed together or bump into each other a lot, ___________ leave one surface and collect on the other
+ example
ELECTRONS
ex. Socks rubbing against a carpet
Some materials —– electrons and end up with a NEGATIVE charge
GAIN
Some materials —- electrons and end up with a POSITIVE charge
LOSE
What is a electroscope?
a piece of equipment used to detect electrical charges
What are the two different types of electroscopes?
Pith‐Ball Electroscope
Metal Leaf Electroscope
what does a Metal Leaf Electroscope detect?
used to detect electrical charge
how does a Pith‐Ball Electroscope work?
Pith (plant material) is suspended by a thread, bring a charged object near the pith which is neutral. If the object is charged, the pith will be attracted to it
What is the 3 laws of electrical charge?
Like charges repel
Opposite charges attract
A neutral object attracts both positively and negatively charged objects
are most objects are neutral (uncharged) because they have the same number of positive and negative charges?
true!
what two factors affect the force between charged objects?
- Distance
closer = stronger force
far = weaker force
- Amount of charge on each object
smaller charge = weaker force
larger charge = stronger force
What are three methods of charging?
- by friction
- by conduction
- by induction
what happenes when two neutral objects are brought together?
there is NO ATTRACTION
what is an Induced charge separation?
is a shift in the position of electrons in a neutral object that occurs when a charged object is brought near it
what charge will the object be after an induced charge seperation?
Neutral charge
Although there is a shift in the positions of the electrons in the neutral object, it is still neutral – it did not gain or lose electrons.
Is an induced charge seperation permanent or temporary?
temporary
What happens when the object is moved away from the neutral object?
the electrons will return to their normal positions
what happenes when negative charged object is BROUGHT NEAR a metal leaf electroscope?
electrons transfer into the leaves, causing them to repel & spread apart
What happenes when the negative charged object is REMOVED from the metal leaf electroscope?
the metal leaf electroscope is brought back to normal
how do electrostatic paint sprayers work?
- paint is given a charge as it leaves the paint nozzle
- object is given the opposing charge
- charged paint particles will be attracted to the object
What are two common methods of charging by contact?
charging by FRICTION
charging by CONDUCTION
Does charging by Induction involve the objects touching each other?
NO! Charging by Induction DOES NOT involve the objects touching each other.
What is charging objects by friction?
transfer of electrons between two neutral objects (made from different materials)
that occurs when they are rubbed together or come in contact (touch)
In friction which charges would each object have?
One material is more likely to attract extra electrons (become negatively charged)
while the other material is more likely to give up electrons (become positively charged)
How could we know which materials will give away electrons more easily?
using the electrostatic series (also called the triboelectric series)
what is the electrostatic series?
a list of materials arranged in order of their tendency to gain electrons
It is a list of the ABILITY of substances to hold on to their ELECTRONS
USED FOR FRICTION
how can the electrostatic series be determined?
can be used to determine which substances will get a NEGATIVE CHARGE and which will get a POSITIVE CHARGE
What charge will the substance be if
ELECTRONS ARE LOST
(electrostatic series)
If electrons are lost → positive charge
What charge will the substance be if
ELECTRONS ARE GAINED
(electrostatic series)
If electrons are gained → negative charge
When rubbed together, the substance that is closer to the bottom of the electrostatic series will become —-, the one closer to the top will become ——
closer to the bottom becomes - negative
closer to the top becomes - postive
how does conduction work?
Electrons can be passed on between two objects with different amount of electric charge if they touch each other (not rubbed, just touched)
What happenes to an uncharged (neutral) object during conduction?
Uncharged (neutral) objects can become charged if they come into contact with charged objects.
What happens if a negatively charged ebonite rod touched a neutral pith ball during CONDUCTION?
If a negatively charged ebonite rod touches a neutral pith ball, the pith ball will also become negatively charged. The two objects will now have the same charge and will repel each other.
What happenes when an uncharged object is charged with a neutral one during CONDUCTION?
When an uncharged object is charged with a neutral one, it will take on the same charge as the one that touches it.
What happenes when a positvely charged object touches a neutral object?
electrons move to the positively charged object
in the end BOTH end up with SAME overall charge (POSITIVE CHARGE)
what happenes when a negatively charged object touches a neutral object?
electrons will move to the neutral object
in the end BOTH end up with SAME overall charge (NEGATIVE CHARGE)
Can only electrons move?
Yes!! only electrons can move as protons are trapped in the nucleus, so they cannot move
What is grounding?
directing the electricity into the ground with a conductor,
can be a way to protect ourselves against an electric shock
Do people who work around of alot of electric charge wear grounding straps?
yes!! Some people who work around a lot of electric charge wear grounding straps to protect themselves against an electric shock
What happenes to a negatively charged object in grounding?
electrons will MOVE TO the ground until object becomes neutral
what happenes to a postively charged object in grounding?
electrons will MOVE FROM the ground until the object becomes neutral
Whats an example of an Electrostatic dusters?
How does it work?
Swiffer Duster
- Uses electrostatic charges to attract dust
- When a duster is swept across an object, it causes a buildup of charge on the duster
- The neutral dust is attracted to the duster and jumps from the dusty surface to the duster
What is an example Electrostatic precipitators?
air purifiers & smoke stacks
Device that uses electrostatic charge to remove soot and dust particles from the air
When smoke passes through the negatively charged plates,the particles of smoke become negatively charged through conduction
These particles than pass through a second plate which is positively charged. They are attracted to the +ve charge (since they are -vely charged)
What is a conductor?
- materials that allow electrons to move freely through them
- when they are charged with static the charge distributes everywhere.
What are some examples of good conductors?
metals - copper wires, silver, gold, steel, sea water
what is a insulator?
- materials that do not allow electrons to move freely through them
- Static charge remains in place in an insulator
- They can be used to protect us from electric shocks (eg. wires are often covered in plastic)
what are some good examples of insulators?
rubber, glass, oil, diamond, dry wood
what everyday items rely on both properties of conductors and insulators?
a laser printer uses BOTH insulators & conductors
when objects can be charged by _______ when they come into contact with another object
objects can be charged by conduction when they come into contact with another object
Can we charge an object without contact?
Yes!
Charging by INDUCTION: charging a neutral object by bringing another charged object close to, but not touching, the neutral object.
Objects can be temporarily or permanently charged by ________
Induction
What happenes when a charged object is brought near a neutral object during temporary induction?
when a charged object is brought NEAR a neutral object, it causes electrons to shift in position= uneven distribution of charges.
Once the charged object is moved away, the electrons will move back to their original positions
What is an example of temporary induction?
Ex. when a negatively charged ebonite rod is brought near but not touching a neutral pith ball, the electrons in the pith ball are repelled by the electrons in the rod. So the side of the pith ball closest to the rod becomes temporarily positively charged while the far side becomes temporarily negatively charged.
Build up of dust on a computer screen is an example of temporary induction
How can an object be permanently charged by induction?
An object can be permanently charged by induction by GROUNDING THE OBJECT
what is an example of temporary charged
Ex. when a negatively charged ebonite rod is brought near but not touching a neutral pith ball, the electrons in the pith ball are repelled by the electrons in the rod. So the side of the pith ball closest to the rod becomes temporarily positively charged while the far side becomes temporarily negatively charged.
If you ground the negatively charged side with your hand, some electrons will move from the pith ball to your hand which leaves the pith ball with a positive charge.
Charging by induction (permanently) always results in …
Charging by induction (permanently) always results in two objects with opposite charges
When charging induction permanently
The object that caused the charge….
and the object that was induced will receive….
The object that caused the charge, keeps its original charge
The object that was induced will receive the opposite charge
what are some Technological applications of charging by induction?
Electrostatic lifting apparatus (used to make copies of footprints)
Electrostatic speakers
What is electric discharge?
rapid transfer of electric charge from one object to another
How does electric discharge work?
Electrons always move from the object with the more negative charges TO the object with the less negative charge
This discharge can sometimes be seen as sparks
The greater the charge imbalance (difference in charges), the larger the discharge , (can sometimes damage electronics or burn skin)
what is lightning?
Lightning is a natural process where electric charges are moving through the air.
electric discharge that occurs between clouds or between clouds on the ground
How do we see lightning?
We see lightning as a jagged path caused by electric charges trying to find the shortest path to the ground
The charges are drawn to tall buildings because these are the shortest path to the ground
What are lightning rods?
- may be placed on the top of a building to provide a safe path for lightning to follow to the ground
- usually made of metal (a conductor) and is long and pointed so it will be the tallest part of the building
lightning always try to take the shortest path to the ground
so the lightning rod will be struck first.
The charge will then be channeled down into the ground
lighting will always try to take the ——– path to the ground
shortest
What are 3 ways static electricity can charge by?
- friction
- conduction
- induction
What are two different types of lightning?
- towards the ground
- from the ground
What do lightning rods do?
Allow lightning to be grounded
How does lightning work?
- water droplets in clouds rub against each other becoming charged. Electrons move from the rising water molecules to the falling water droplets
- This results in negatively charged water molecules collecting at the bottom of the cloud
- excess negative charge at the bottom of the cloud repels the electrons on Earth’s surface directly below the cloud. Making electrons on Earth move away, leaving the area under the cloud positively charged
- eventually charge imbalance between the bottom of the cloud and Earth’s surface becomes large and excess electrons rapidly transfer from the cloud (negatively charged) to the ground (positively charged)
- this transfer of electrons superheats the air around it which causes both the flash of light and the rumbling sound of thunder
During lightning the cloud is commonly…
(CHARGE)
negatively charged
During lightning the groud is commonly….
(CHARGE)
positively charged
What is DC?
Direct current
Direct current is the flow of electrons in one pathway
electrons flow in one direction
- produced by battery to power portable devices
What is AC?
Alternating Current
Alternating current is electrons flowing in various directions and the voltage does not stay constant.
electrons move back and forth, alternating direction
- produced by generators
-efficent in distributing over long distances - wall outlets have AC
What is the difference between Current and Static Electricity?
Static Electricity is when electrons gather on a surface and move randomly in all directions while current is the steady flow of electrons through a conductor
What are the parts of a circuit?
Circuits
a Switch
Load
Electric cell
Lamp
Resistor
What is the purpose of a circuit?
Circuits - a pathway where current electricity flows through
What is the purpose of a switch?
a Switch - opens or closes the circuit to allow the flow of electricity
What is the purpose of a load?
Load - Converts electrical energy into other usable forms.
What is the purpose of a Electrical cell?
Electric cell - converting chemical energy into electrical energy.
What is the purpose of a Lamp?
Lamp - Indicates the flow of electrons in the circuit by glowing or lighting up
What is the purpose of a Resistor?
Resistor - A component of the circuit which can slow down the flow of electrons
What is a parallel circuit?
A parallel circuit has different pathways or branches which allow electrons to flow through various pathways.
What is a series circuit?
A series circuit has all parts of a circuit connected to the same pathway which allows electrons
What is resistance?
Resistance is a component in a circuit which is designed to slow down the flow of electrons
Resistance is the thing that resists current
measured with the unit “ohms” and is denoted with the symbol “Ω”.
The symbol for resistance is “R”
What is voltage?
Voltage is the difference in electric charge between two points.
Voltage is the pressure that causes current to flow.
It’s measured with the unit “volts” and is denoted with the symbol “V”.
The symbol for voltage is also “V”
What is current?
Current is the rate at which electrons pass a point in a circuit
Current is the flow of electrons.
It’s measured with the unit “amperes” and is denoted with the symbol “A”.
The current symbol is “I”.
What happens when a lightbulb is removed from a series and parallel circuit?
When a lightbulb is removed from a series circuit, which means the current flow will be interrupted because it is a single pathway and all the lightbulbs will stop functioning. (One pathway, so the current flow is affected)
A Parallel circuit will not be affected, the lightbulbs are connected in different pathways and only the pathway that had the light bulb removed will be affected because they don’t depend on the same pathway. (The current flow won’t be affected because there are different pathways)
What happens when a switch is closed?
A series circuit has one pathway, therefore; all lightbulbs in the circuit will be powered while in parallel, there are different branches or pathways so only the lightbulb controlled by the certain switch will be affected/powered.
How to make a light bulb brighter?
The brightness of a light bulb depends on the rate at which the electrons flow, therefore; removing a resistor will increase the speed at which electrons pass a point in the circuit and the voltage will increase, and as more voltage passes through the light it becomes brighter.
Patterns in Resistance, Voltage, And Current in SERIES CIRCUIT
The total voltage is the sum of the voltage on each load.
The current is the same everywhere
The total resistance is equal to the sum of the resistance at each load.
Patterns in Resistance, Voltage, And Current in PARALLEL CIRCUIT
Voltage is the same everywhere
The total current is equal to the sum of the current at each load.
Formula for current?
I=V/R
Formula for voltage?
V= IxR
Formula for resistance?
R=V/I
what are electrical circuits?
a continous pathway where electrons could flow in
WHAT IS THE OHMS TRIANGLE?
V
I R
In a parallel circuit the Voltage (V) is ——– at any load
same
In a series circuit the Voltage (V) is ——– between loads
shared
In a parallel circuit the current ( A) is —- between loads
shared
In a series circuit the current ( A) is the —- at all points of the circuit
same
A battery has ——- potential energy
chemical
Potential difference
- Voltage
- difference in electric potential between two points in a circuit
- using VOLTMETER to measure
- must be in paralell with load or energy source
-unit is Volts (V)
what is electrical current?
measure of amount of electric charge that passes by a point in an electrical circuit each second
What is a Ammeter?
- unit of measure is Ampere ( A )
- must be connected in SERIES
- measured using AMMETER
generators
produces energy by rotating a wire coil near a magnet
What is a Electrical energy distribution grid?
carries electricity from energy generating station to a consumer
Pros & Cons of hydrogen fuel cells
Con: doesn’t happen naturally requires alot of pollution to create
pros: light & compact
What are fuel cells?
special kind of electric cell where continuous supply of chemicals is pumped as the cell operates
ex. hydrogen fuel cell
What is an electric cell?
device that converts chemical energy to electrical energy
primary cell: can be used only once
secondary cell: can be recharged
what are two main sources of electrical energy?
batteries - supply small amounts of electrical energy
electric generating stations - deliver large amounts of electrical energy
What is electrical energy?
energy provided by flow of electrons in an electrical circuit
measured in joules (J) or kilojoules (KJ)
What does an electrical circuit need?
Energy source (battery)
Load (light bulbs)
Connecting Wires
A Switch - SOMETIMES:
what are electrical circuits?
a continous pathway where electrons could flow in
what is current electricity?
flow of electric charge through a conductor (wires)
