# 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
W
water vapour: Water in gaseous form.
watt (W): The unit of power. 1 W is equivalent to 1 J (joule) per second of energy transformation.
wave: A travelling disturbance passing through a medium.
weathering: The physical breakdown and chemical alteration of rocks and minerals at or near Earth’s surface.
white dwarf: The final stage of a star.