# Physics:  The Characteristics of Electricity Julian Not Sin Wai Poo
Get Started. It's Free Physics:  The Characteristics of Electricity ## 1. Characteristics of Electricity Static Electricity

### 1.1. static electricity

1.1.1. electrostatics

1.1.1.1. the study of static electricity

1.1.2. friciton

1.1.2.1. the force resisting the relative motion of two surfaces in contact (rubbing different substances together)

1.1.3. static

1.1.3.1. "at rest", not moving or stationary because the charges are hardly moving until they are given a path of escape

1.1.4. static charge

1.1.4.1. the electric charge that builds up on the surface on the surface of the object

1.1.5. conductor

1.1.5.1. a material that allows electrons to change positions easily, can channel electrons easily

1.1.6. insulator

1.1.6.1. a material that resists or blocks the movement of electrons, does not channel electrons very well

### 1.2. charging objects

1.2.1. charge by friction

1.2.1.1. neutral ebonite rod with a neutral cotton cloth

1.2.1.2. when they are rubbed together, electrons move from the cotton to the ebonite

1.2.1.3. the cotton cloth is now positively charged and the ebonite rod is now negatively charged

1.2.2. charge by contact or touch (negative)

1.2.2.1. neutral ebonite rod and negatively charged steel sphere

1.2.2.2. electrons move from the sphere to the rod during contact

1.2.2.3. the ebonite rod is now negatively charged and the steel sphere remains negatively charged

1.2.3. charge by contact or touch (positive)

1.2.3.1. neutral ebonite rod and positively charged

1.2.3.2. electrons move from the rod to the sphere during contact

1.2.3.3. the ebonite rod is now positively charged and the steel sphere remains positively charged

1.2.4. charge by induction

1.2.4.1. induction is the movement of electrons within a substance caused by a nearby charged object without direct contact between the substance and object

1.2.4.2. an induced charge can become a permanent charge through grounding, which is the process of connecting a charged object to the Earth's surface

1.2.4.3. negative sphere

1.2.4.3.1. neutral rod and negatively charged sphere

1.2.4.3.2. electrons in the rod are repelled from the sphere and creates temporarily charged area

1.2.4.3.3. the rod is grounded and electrons flow out of the rod into the ground

1.2.4.3.4. the rod is now positively charged and the sphere remains negatively charged

1.2.4.4. positive sphere

1.2.4.4.1. neutral rod and positively charged sphere

1.2.4.4.2. electrons in the rod are attracted to the sphere and creates temporarily charged area

1.2.4.4.3. the rod is grounded and electrons flow into the rod from the ground

1.2.4.4.4. the rod is now negatively charged and the sphere remains positively charged

1.2.5. attraction and neutral objects

1.2.5.1. neutral rod and negatively charged sphere

1.2.5.2. electrons in the rod are repelled from the sphere creating a temporarily charged area

1.2.5.3. the positives that remain on side of the rod are then attracted to the negatively charged sphere

## 2. Current Electricity

### 2.1. current electricity, circuits, and cells

2.1.1. current electricity

2.1.1.1. the electricity produced by the continuous flow of electrons

2.1.2. circuit

2.1.2.1. a path that electricity can flow though

2.1.2.2. closed circuit means the energy can flow through, open circuit means there is a break in the path

2.1.3.1. a device that converts electrical energy to another type of energy

2.1.4. battery

2.1.4.1. a combination of electrochemical cells that produces electrical energy

2.1.5. electrochemical cell

2.1.5.1. a package of chemicals that converts chemical energy into electrical energy that is stored in charged particles

2.1.5.2. includes an electrolyte and two electrodes

### 2.2. potential difference/voltage

2.2.1. potential difference/voltage

2.2.1.1. a difference in energy at different points of the circuit

2.2.1.2. the symbol for voltage is V

2.2.2. volt

2.2.2.1. the unit of measurement for potential energy

2.2.3. voltmeter

2.2.3.1. a tool that measures the potential difference between two locations in a circuit

### 2.3. current

2.3.1. electric current

2.3.1.1. a measure of the amount of electric charge that passes a point in a circuit each second

2.3.1.2. the symbol for current is I

2.3.2. direct current

2.3.2.1. a current that only flows in one direction

2.3.3. alternating current

2.3.3.1. a current that flows back and forth at regular intervals called cycles

2.3.4. ampere

2.3.4.1. the unit of measurement for electrical current

2.3.5. ammeter

2.3.5.1. a tool that measures current in a circuit

### 2.4. resistance

2.4.1. resistance

2.4.1.1. the degree to which a substance opposes the flow of electric current though it

2.4.1.2. the symbol for resistance is R

2.4.2. resistor

2.4.2.1. any material that can slow current flow

2.4.3. ohms

2.4.3.1. the unit of measurement for resistance

2.4.4. ohmmeter

2.4.4.1. a tool used to measure resistance

### 2.5. series and parallel circuits

2.5.1. series circuit

2.5.1.1. a circuit that has only one path for the current to flow

2.5.1.2. an electrical circuit in which the components are arranged one after another in a series

2.5.1.3. adding more resistors causes the total resistance to increase

2.5.1.4. each load uses a portion of the total potential difference supplied by the battery

2.5.1.5. the current is the same throughout a series circuit

2.5.1.6. the current decreases when more resistors are added

2.5.2. parallel circuit

2.5.2.1. a circuit that has more than one path for the current to flow

2.5.2.2. an electrical circuit in which the parts are arranged so that electrons can flow along more than one path

2.5.2.3. adding more resistors decreases the total resistance of the circuit

2.5.2.4. each load uses all the potential difference supplied by the battery

2.5.2.5. the current divides into different paths, a pathway with less resistance will have greater current

2.5.2.6. adding resistors in parallel decreases the total resistance of the circuit

2.5.3. junction point

2.5.3.1. the point where a circuit divides into different paths or where paths combine

## 3. Investigating Circuits

### 3.1. investigating Ohm's law

3.1.1. equation for finding voltage

3.1.1.1. V=IR

3.1.2. equation for finding current

3.1.2.1. I=V/R

3.1.3. equation for finding resistance

3.1.3.1. R=V/I

### 3.2. short circuits and electrical safety

3.2.1. fuse

3.2.1.1. a safety device in an electrical circuit that has a metallic conductor with a low melting point compared to the circuits' wires

3.2.1.2. if the connecting wire is hotter than usual, the fuse will melt and the circuit will open, stopping the current

3.2.2. circuit breaker

3.2.3. a safety device in an electrical circuit that is very similar to the fuse, except the device does not melt

3.2.4. when the wire in the circuit breaker heats up, it bends and triggers a spring mechanism that stops the flow of electricity

3.2.5. three-prong plug

3.2.5.1. the third prong on plugs is a ground to prevent electrocution

3.2.5.2. excess current would flow to the ground through the third prong instead of through a human body

3.2.6. GFCI

3.2.6.1. ground fault circuit interrupter/residual current device

3.2.6.1.1. a device that detects a change in current and if a change is detected, it opens the circuit to stop current flow

## 4. The Future of Electrical Energy Production and Consumption

### 4.1. generating electricity

4.1.1. non-renewable resourses

4.1.1.1. a resource that cannot be replaced once it is used up

4.1.2. renewable resourses

4.1.2.1. a resource that can be reused or replaced

4.1.3. generators

4.1.3.1. machines that use electromagnetic induction to produce energy through motion

4.1.4. turbine

4.1.4.1. the part in the generator that rotates the magnets

4.1.5. energy grid/distribution grid

4.1.5.1. the web of interconnections between generating stations and users

### 4.2. alternative ways to generate electricity

4.2.1. solar energy

4.2.1.1. using the power from the sun to generate energy

4.2.2. wind energy

4.2.2.1. using the power of wind to generate energy

4.2.3. tidal energy

4.2.3.1. using the difference in tides to generate energy

### 4.3. what can we do at home?

4.3.1. kilowatt-hour (kw·h)

4.3.1.1. the use of one kilowatt in one hour

4.3.1.2. for example:  a microwave uses 0.8kw in half an hour E=0.8kwx0.5h E=0.4kw·h

4.3.2. efficiency

4.3.2.1. the ratio of the useful energy that comes out of the device to the total energy that went in

4.3.3. percent efficiency

4.3.3.1. equation for percent efficiency

4.3.3.1.1. Energy out/Energy in x 100

4.3.4. EnerGuide

4.3.4.1. a label that states how much energy an appliance will use in a month or year of average usage

4.3.5. Energy Star

4.3.5.1. a symbol on an EnerGuide label meaning that appliance is one of the most efficient in its class