EVAPORATION When heat is transferred to liquid water and causes the molecules of H2O to move rapidly and spread apart, causing the liquid to change state into a gas, water vapor.

CONDENSATION Process in which water vapor changes into a liquid, usually after coming in contact with air that is cooler than the water vapor.

PRECIPITATION Water falling from clouds as rain, snow, sleet or hail.

RUNOFF Any rainwater that does not soak into the ground or evaporate but flows over Earth’s surface; flows into streams, erodes and carries sediments.

CONDUCTION A process which transfers energy when molecules bump into each other. Example: When a pot touches a stove or your hand touches a hot pan.

CONVECTION The transfer of heat by the flow of material, this can be in air, water or even in the mantle of the earth.

RADIATION The process in which energy is transferred by waves or rays.

IMPERMEABLE ROCK Rock that will not allow water to soak in or penetrate.

WATER TABLE The upper surface in the saturated rock underground.

PERMEABLE ROCK Rock with connecting pores through which water can flow. Examples: limestone and sandstone.

FLOODPLAIN The flat land located beside a river or stream where flood waters flow during heavy rains.

RIVER MEANDER A broad, C-shaped curve in a river or stream, formed by erosion from swift moving water on its outer bank.

SUBLIMATION When snow or ice converts directly into water vapor.

INFILTRATION When water is absorbed into the Earth through the soil and permeable rock.

TRANSPIRATION The loss of water vapor from plants.