• hydrosphere
    Catch a wave, and you're sitting on top of the hydrosphere.

    Hydrosphere in Space
    Some scientists believe a hydrosphere exists on Europa, a moon of Jupiter, that consists of a frozen outer layer and a giant, liquid ocean underneath it.

    A hydrosphere is the total amount of water on a planet. The hydrosphere includes water that is on the surface of the planet, underground, and in the air. A planet's hydrosphere can be liquid, vapor, or ice.

    On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground—as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog.

    The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs. The frozen part of the hydrosphere has its own name, the cryosphere.

    Water moves through the hydrosphere in a cycle. Water collects in clouds, then falls to Earth in the form of rain or snow. This water collects in rivers, lakes and oceans. Then it evaporates into the atmosphere to start the cycle all over again. This is called the water cycle.

  • Term Part of Speech Definition Encyclopedic Entry
    aquifer Noun

    an underground layer of rock or earth which holds groundwater.

    Encyclopedic Entry: aquifer
    atmosphere Noun

    layers of gases surrounding a planet or other celestial body.

    Encyclopedic Entry: atmosphere
    cloud Noun

    visible mass of tiny water droplets or ice crystals in Earth's atmosphere.

    Encyclopedic Entry: cloud
    cryosphere Noun

    icy part of the Earth's waterincluding icebergs, glaciers, and ice caps.

    Earth Noun

    our planet, the third from the Sun. The Earth is the only place in the known universe that supports life.

    Encyclopedic Entry: Earth
    Europa Noun

    moon of Jupiter.

    evaporate Verb

    to change from a liquid to a gas or vapor.

    fog Noun

    clouds at ground level.

    Encyclopedic Entry: fog
    glacier Noun

    mass of ice that moves slowly over land.

    Encyclopedic Entry: glacier
    groundwater Noun

    water found in an aquifer.

    Encyclopedic Entry: groundwater
    hydrosphere Noun

    all the Earth's water in the ground, on the surface, and in the air.

    Encyclopedic Entry: hydrosphere
    ice Noun

    water in its solid form.

    Encyclopedic Entry: ice
    iceberg Noun

    large chunks of ice that break off from glaciers and float in the ocean.

    Encyclopedic Entry: iceberg
    ice cap Noun

    area of fewer than 50,000 square kilometers (19,000 square miles) covered by ice.

    Encyclopedic Entry: ice cap
    Jupiter Noun

    largest planet in the solar system, the fifth planet from the Sun.

    lake Noun

    body of water surrounded by land.

    liquid Noun

    state of matter with no fixed shape and molecules that remain loosely bound with each other.

    ocean Noun

    large body of salt water that covers most of the Earth.

    Encyclopedic Entry: ocean
    planet Noun

    large, spherical celestial body that regularly rotates around a star.

    Encyclopedic Entry: planet
    rain Noun

    liquid precipitation.

    Encyclopedic Entry: rain
    river Noun

    large stream of flowing fresh water.

    Encyclopedic Entry: river
    snow Noun

    precipitation made of ice crystals.

    vapor Noun

    visible liquid suspended in the air, such as fog.

    water cycle Noun

    movement of water between atmosphere, land, and ocean.

    Encyclopedic Entry: water cycle
    well Noun

    a hole drilled in the Earth to obtain a liquid or gaseous substance.