electricity

• protons are positive
• neutrons are neutral
• electrons are negative
• like charges repel, unlike charges attract
• friction within clouds causes electrons to build up at the bottom of the clouds
• adding extra cells gives more power and current flows
• adding bulbs increases resistance and less current flows
• potential difference is measured during a voltmeter
• current is measured using an ammeter
• voltmeter = across, ammeter = through
• voltage = current x resistance (V = IR)
• resistance = ohms
• potential difference of a battery tells you the voltage and how much energy can be transferred
• a series circuit has one pathway for electrons to flow around
• the higher the potential difference, the more energy that will be transferred to the bulb
• magnetic field - a region around a magnet where a magnetic material experiences a force
• magnetic fields are stronger at the poles
• a nucleus is a small dense mass of protons and neutrons in the centre of an atom
• static electricity is an electric charge that does not move
• electrons are removed from the atoms of one material and are collected on the atoms of another material which makes in into charged ions
• when two materials rub together they can become statically charged
• an insulator is a substance that doesn't allow electrons to flow through it easily
• a conductor allows electrons to flow freely through it
• torch

  A) circuit

  B) button

  C) bulb

  D) 2x cells (battery)

  
• adding an ammeter to the circuit will decrease the current in the circuit as the ammeter will decrease the resistance
• ..

  
• current flows from positive to negative
• types of circuits

  A) parallel

  B) series

  
• series circuit = if one bulb goes out, the current in the remaining bulbs stays the same
• parallel circuit = if one bulb goes out the others will as well
• series circuit = current the same all the way around
• parallel circuit = current is split between branches and each branch has the same potential difference
• potential difference (V) = energy transferred per unit charge
• power (P) = rate at which work is done or energy transferred
• energy transfered by an appliance = power x time
• energy transfer = power x time