# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
T
temperature: A measure of the average total kinetic energy of all the atoms contained within a substance. Temperature is measured with thermometers, in Celsius or Kelvin units.
tempering: A method of strengthening a metal where a metal that has first been quenched is heated again to a lower temperature than the original temperature and allowed to cool slowly.
tension forces: Forces that stretch an object.
tetrahedral lattice: A three-dimensional arrangement of a molecule.
thermal equilibrium: This is when two objects are at the same temperature. When two objects of different temperatures are brought together, thermal equilibrium will eventually occur.
thermistor: A device used in electric circuits that changes its resistance depending on its temperature.
thermometer: A device that measures temperature.
thermoplastic polymer: A polymer that can be melted and shaped.
thermosetting polymer: A cross-linked polymer that that, once formed, cannot be melted or reformed.
thermosphere: The layer of the atmosphere that absorbs solar radiation; it is between 80 km and 110 km from Earth’s surface.
thixotropic liquid: A non-Newtonian fluid. Thixotropic liquids decrease in viscosity under a constantly applied force and are sometimes called ‘stir-thinning liquids’.
thrust: Forward force on an object in flight.
transformer: A device that raises or lowers alternating current (AC) voltages using two coils of wire wound around an iron, circular core.
transistor: A device used in electric circuits to amplify or magnify small alternating currents or voltages.
transition element: An element that has an unfilled shell in its electronic configuration.
transparency: The ability of a substance to allow light to pass through it.
transparent material: Material that allows light to pass through it.
transpiration: This is when plants expel water vapour into the atmosphere.
transverse wave: A travelling disturbance (wave motion) in a material where the particles vibrate perpendicular to the direction of the motion of the disturbance.
triple bond: A triple covalent bond between two atoms in a molecule.
tropical year: The length of time between two vernal equinoxes.
troposphere: The lowest layer of the atmosphere.
tsunami: A destructive sea wave that is usually produced by an earthquake but can also be caused by submarine landslides and volcanic eruptions.