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Glossary
absorb
when a liquid soaks into a
material
air pressure
the force exerted on a
surface by the mass of the air above it
anemometer
a weather instrument that
measures wind speed with wind-catching
cups
aquifer
water that is underground in
layers of rock or sediment
barrier island
a strip of narrow land a
short distance from shore
blade
the part of a waterwheel that the
water pushes as it moves downward
boiling point (100°C)
the temperature
at which water changes to gas
Celsius (°C)
the basic unit of temperature
in the metric system. Water freezes at 0°C
and boils at 100°C
climate
the average or typical weather
conditions in a region of the world
cloud
tiny droplets of water, usually high
in the air
compass
a magnetic needle in a case.
Compass needles on Earth point north.
condense
when water vapor touches a
cool surface and becomes liquid water
conserve
to use carefully and protect
contract
to get smaller; to take up less
space
criterion (
plural
criteria)
a need or
requirement
decomposing organic matter
humus;
dead or discarded parts of plants and
animals
density
the amount of mass compared to
the volume
dew
water that condenses on a surface
when the temperature drops at night
drought
a less-than-normal amount of
rain or snow over a period of time
electricity
energy that flows through
circuits and can produce light, heat,
motion, and sound
energy
the ability to make things happen.
Energy can take a number of forms, such
as heat and light.
energy source
a place where energy
comes from, such as coal, petroleum, and
natural gas
engineer
a scientist who designs ways to
accomplish a goal or solve a problem
evaporate
when liquid water in a
material dries up and goes into the air
evidence
data used to support claims.
Evidence is based on observation and
scientific data.
expand
to get bigger; to take up more
space
float
to stay on the surface of water as a
result of being less dense than water
flood
a large amount of water flowing
over land that is usually dry
floodplain
the flat, low land area next to
a river that may flood
force
strength or power exerted on an
object
forecast
to predict future events or
conditions, such as weather
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