science

• Electricity


  The flow of electrical power or charge between two conductors that supply it to a circuit
• Voltage


  The energy applied to push electric charges through a circuit, measured in volts
• Current


  The flow of electric charges through a circuit, carrying energy from the source to the components, measured in amperes (amps)
• Resistance


  The property of a material that hinders the flow of electric charges, causing energy to be dissipated as heat, measured in ohms
• Ohm's Law


  Current (I) is directly proportional to voltage (V) and inversely proportional to resistance (R), expressed as I = V/R
• Insulator


  Materials that do not allow electricity to pass through them and flow freely, e.g. glass, plastic, rubber, air, wood
• Conductor


  Materials that allow electricity to flow through it, e.g. silver, gold, copper, aluminium, iron
• Outer electrons move from one atom to the next when an electric circuit is made
• In a torch the circuit is made when you close the switch
• Moving electrons have electrical energy, some of which is used to make light energy, sound energy, heat energy, and kinetic energy in the appliances we use
• Electricity is the movement of electrons from one atom to the next
• When you turn the electricity on, some electrons around atoms shuffle from one atom to the atom next to them
• Metals are conductors of electricity
• In rubber and plastic, the electrons are held tightly and a lot of energy is needed to pull an electron out and move it to the next atom, so these substances are insulators
• Semiconductor


  The conductivity of a semiconductor is somewhere between that of an insulator and a conductor, e.g. silicon
• Fuse


  A special type of resistance wire that gets hot and melts when a certain amount of electric current flows, stopping excess current and overheating
• Series circuits


  • Components are connected in a single path, so the same current flows through each component
  • Total resistance is the sum of the individual resistances
• Parallel circuits


  • Components are connected in separate branches, allowing different currents to flow through each branch
  • Total resistance is less than the smallest individual resistance
• Series circuits are used in applications like Christmas tree lights, while parallel circuits are used in homes for electrical outlets
• Law of conservation of energy


  Energy cannot be created or destroyed, only transferred or transformed from one form to another, with some energy always lost as heat due to inefficiencies
• Non-renewable energy


  Energy that cannot be replaced, e.g. coal, oil, gas
• Renewable energy


  Energy that can be replaced, e.g. wood, wind, solar
• Atom


  A particle of matter that uniquely defines a chemical element, consisting of a central nucleus surrounded by one or more negatively charged electrons
• Electron


  An elementary particle that has a negative charge of electricity and travels around the nucleus of an atom
• Calculating averages


  Add all the values together and divide by the number of values
• Energy transformation in a torch

  Chemical Potential energy ⇒ Electrical energy ⇒ Light energy
• When the circuit is closed, electrons are free to flow through it and it allows the flow of an electric current
• When the circuit switch is open, it interrupts and blocks the flow of electric current