science chap 7/8

• Electric energy


  When electric charges become separated
• Electric charge


  A charge of electricity produced by subatomic particles
• Electric current


  The flow of electrical charge throughout a circuit as a result from the movement of negatively charged electrons
• Like charges


  When the charges of objects are the same (both positive or both negative)
• Unlike charges


  When charges of objects are different (one is negative, the other is positive)
• Electrostatic charge


  A positive or negative charge trapped within an object
• Conductors


  Materials that allow charged particles to pass through (e.g. copper metal)
• Insulators


  Materials that do not allow the movement of charged particles (e.g. plastic)
• Semiconductor


  Substances that conduct electricity more than an insulator & less than a conductor (e.g. silicon is an insulator in its pure form when combined with other materials it becomes a conductor so it's a semiconductor)
• Diodes


  A semiconductor device that allows current to flow in one direction only usually made by specially treated silicon
• Conventional current


  Direction of current is the flow of positive charge from positive terminal of energy source to the negative terminal
• Alternating Current (AC)


  Electrons that reverse direction (50 times per second)
• Direct Current (DC)


  Electrons flow in one direction
• Electric current


  A closed pathway that conducts electrons in the form of electrical energy
• Wet Cell


  Contains liquid (usually an acid, e.g.,sulfuric acid)
• Dry Cell


  Contains no liquid
• Short circuit


  When electrical current flows to a different path than intended
• Fuse


  A wire of high resistance that will melt if too much current flows in the circuit
• Voltage


  Potential difference; the difference in potential energy carried by charged particles at different points in a circuit
• Resistance


  A measure of how how difficult it s for the charged particles in an electric circuit to move- measured in 'ohms' (Ω)
• Rectifier


  A device that converts AC to DC commonly composed of diodes
• Voltmeter


  An instrument used for measuring electric potential difference between 2 points in a circuit
• Multimeter


  A versatile electronic device used to measure various electrical properties including voltage, current and resistance
• Electrical circuit


  The pathways travelled by electrical energy
• Direction of current


  Direction of flow of positive charge from positive terminal or energy source to negative terminal
• Electromagnetic induction


  When a magnetic field generates its own electrical current, pushing the electrons within the wire
• Magnet


  A piece of iron or other material that produces a magnetic field
• Temporary magnet


  A temporary magnet is a magnet made of soft iron, that is usually easy to magnetise; however, temporary magnets lose most of their magnetic properties when the magnetising cause is discontinued
• Permanent magnet


  A magnet that retains its magnetism after the removal of the magnetising force
• Attraction


  A pulling force
• Repulsion


  A pushing force
• Electromagnet


  An object that is magnetised when electricity flows through it
• Electromagnetism


  The interaction between magnetic fields and electric currents
• Magnetic


  Attracted to a magnet
• Magnetic domain


  A tiny region with magnetic poles inside a magnetic material. Magnetic substances like iron, nickel and cobalt have magnetic domains and can be magnetised
• Magnetic field


  The space around a magnet where magnetic forces can occur
• Magnetism


  A force exerted on some metals, such as iron and nickel. Magnetism is a fundamental type of non-contact force that can be either attractive or repulsive
• Magnetised


  Behaving like a magnet
• Non- contact force


  Any force that can occur even when two objects are not touching. Eg. gravity and magnetism
• Non-magnetic


  Not attracted by a magnet