# introduction to electricity static electricity and electrical charge

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• Slide 1
• Introduction to Electricity Static Electricity and Electrical charge
• Slide 2
• Slide 3
• Atoms and charge Atoms are made of protons, neutrons and Electrons. Protons- positive Neutrons- neutral Electrons- negative Charges of particles
• Slide 4
• Law of Electrical charges Like charges repel and opposite charges attract. The force between charged objects is Electrical force.
• Slide 5
• Slide 6
• Slide 7
• Electrical force Strength of electrical force determined by Size of the charge -greater charge = more force Distance from charge- close=greater
• Slide 8
• Charging atoms Objects can become charged because Atoms can either gain or lose electrons Gain electrons = negative charge Lose electrons= positive charge Atoms cant lose protons or neutrons!!
• Slide 9
• Charge by friction Rubbing 2 objects together to separate Positive and negative charges.
• Slide 10
• Charging by conduction When electrons are transferred from one Object to another by direct contact
• Slide 11
• Charge by induction Occurs when charges in uncharged object Are rearranged without direct contact With charged object
• Slide 12
• Conservation of charge Charges are not created nor destroyed, Just moved from atom to atom
• Slide 13
• Detecting charge Electroscope can detect if an object is charged
• Slide 14
• Moving electrical charges Materials are divided into 2 groups based On how easily a charge can travel through it Conductors or Insulators
• Slide 15
• Conductors Allow charges to move easily through them Electrons in metals are free to move about Used to make wires Not always metals (water)
• Slide 16
• Insulators Materials that do not allow easy charge movement Electrons are tightly bound Used to coat conductors to prevent shock
• Slide 17
• Static electricity Build-up of electrical charge Charges are not moving Created by opposite charges
• Slide 18
• Lightning Occurs when charge is separated in cloud And induces opposite charge on the surface
• Slide 19
• Section 2 Electrical energy Batteries uses chemical reactions to Produce electrical energy.
• Slide 20
• Batteries Cells- device that produces an electrical current by converting chemical energy to electrical energy. Battery- uses several cells to make energy
• Slide 21
• Parts of a cell Batteries contain electrolytes (a mixture of chemicals) Chemical reaction in electrolytes convert chemical energy to electrical energy
• Slide 22
• Simple cell Pair of electrodes made from 2 different conducting metals are In contact with electrolyte. Electrode- part of a cell through which charges enter and exit.
• Slide 23
• Types of cells Dry cells- use solid or paste-like electrolyte Wet cells- use sulfuric acid as electrolyte
• Slide 24
• Potential difference Energy per unit charge expressed in volts Chemical reaction causes difference in charge between electrodes. More cells = more potential difference
• Slide 25
• Other ways to produce electrical energy Photocells- solar panel converting light to Electrical energy Thermocouple- thermal energy converted To electrical energy
• Slide 26
• Section 3 Electric Current Current- rate at which charge flows Ampire (AMP)- unit for current Voltage- difference between energy per unit charge
• Slide 27
• AC/DC AC or Alternating current- current can flow any direction in a wire home wiring DC or Direct current- current only flows in one direction. Batteries, flashlights
• Slide 28
• Voltage and resistance US households supply a voltage of 120 V Resistance opposition of flow of electrons Think of this as electrical friction. Resistance is expressed in OHMs As resistance increases, current decreases
• Slide 29
• Factors that affect resistance Conductor type- copper good, iron bad Thickness of wire thicker wires decrease resistance Length of wire- longer wires increase resistance Temperature- higher temps = higher resistance
• Slide 30
• Ohms Law Shows voltage, current and resistance Are related with the following equation V = I x R R = V / I I = V / R V = voltage R= Resistance I= Current
• Slide 31
• Electrical Power The rate at which electrical energy is used To do work. Power (W) = voltage (V) X current (Amps)
• Slide 32
• Power rating Measured in watts for light bulbs and all Electrical appliances and devices Kilowatt-hours for measuring household Electricity use.

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