kinetic theory
explanation of the behavior of molecules in matter; states that all matter is made of constantly moving particles that collide without losing energy
melting point
temperature at which a solid begins to liquefy
heat of fusion
amount of energy required to change a substance from the solid phase to the liquid phase
boiling point
the temperature at which the pressure of the vapor in the liquid is equal to the external pressure acting on the surface or the liquid
heat of vaporization
the amount of energy required for the liquid at its boiling point to become a gas
diffusion
spreading of particles throughout a given volume until they are uniformly distributed
plasma
matter consisting of positively and negatively charged particles
thermal expansion
increase in the size of a substance when the temperature is increased
density
mass per unit volume of a material
buoyancy
ability of a fluid (a liquid or a gas) to exert an upward force on an object immersed in the fluid
pressure
amount of force exerted per unit area; SI unit is the pascal (Pa)
viscosity
a fluid's resistance to flow
temperature
measure of the average kinetic energy of all the particles in an object
pascal
SI unit of pressure