H

habitat
Where an organism lives, with distinctive features such as climate or resource availability.
haboob
Desert sandstorms that form in the downdrafts of a thunderstorm.
half-life
The amount of time required for half of the atoms of a radioactive substance to decay to the daughter product.
hanging valley
A cliff where a large glacier cut off the U-shaped valley of a tributary glacier.
hardness
The ability of a mineral to resist scratching.
headwaters
The location where a stream forms, often high in the mountains.
heat
Energy associated with the movement of atoms or molecules that can be transferred.
heat wave
A period of prolonged excessively hot weather for a particular region.
heliocentric model
Model proposed by Copernicus that put the Sun at the center of the universe.
hemisphere
One half of a sphere.
herbivore
An animal that only eats producers.
high pressure zone
A region where relatively cool, dense air is sinking.
high tide
The highest water levels during a day caused by the gravitational pull of the Moon.
hot spring
A stream of hot water that flows out of the ground continuously.
hotspot
A plume of hot material that rises through the mantle and can cause volcanoes.
humidity
The amount of water vapor held in the air.
humus
The partially decayed remains of plants and animals; forms the organic portion of soil.
hurricane
Cyclone that forms in the tropics and spins around a low-pressure center.
hybrid vehicle
A very efficient vehicle that is powered by an internal combustion engine, an electric motor and a rechargeable battery.
hydrocarbon
A chemical compound containing hydrogen and carbon that is used for energy.
hydrogen bond
A weak intermolecular connection between two polar molecules.
hydrologic (water) cycle
The movements of water in and between reservoirs (e.g. oceans, clouds, streams, ice, and ground water).
hydrolysis
Hydrogen or hydroxide ions replace the cations in a mineral to change the mineral.
hydrothermal vent
A stream of heated water that enters into the ocean at a mid-ocean ridge.
hypothesis
A good working explanation for a problem that can be tested.