The water cycle

Study Guide: The Water Cycle

I. Vocabulary

  • Evaporation:

    • The process of a liquid changing into a gas due to an increase in temperature or pressure.

  • Condensation:

    • The process of a gas changing into a liquid due to a decrease in temperature or pressure.

  • Precipitation:

    • Condensed water vapor that falls back to Earth, such as snow, rain, sleet, or hail.

  • Transpiration:

    • Plants absorb water through their roots and then release water vapor through their leaves.

  • Surface Runoff:

    • Precipitation that reaches Earth's surface, flows over land, and eventually reaches lakes, rivers, and oceans.

  • Ground Water:

    • Water that lies beneath the ground.

  • Atmosphere:

    • The thin blanket of gases that surrounds the Earth, held in place by gravity; protects life and regulates temperature.

  • Biosphere:

    • The regions of Earth where life exists, including all forms of plants and animals.

  • Geosphere:

    • The solid Earth consisting of rocks, soil, and minerals; comprises the crust, mantle, and core.

  • Hydrosphere:

    • Water on the surface of Earth, such as lakes and glaciers, as well as vapor in the air and groundwater beneath the surface.

  • Water Vapor:

    • Water in the form of a gas.

  • Crystallization:

    • The process where a liquid turns into a crystalline solid.

  • Reservoirs:

    • Storage areas for water, including oceans, lakes, glaciers, ice caps, and groundwater.

  • Water Cycle:

    • The continuous movement of water from Earth's surface to the atmosphere and back again.

  • Glaciers:

    • Large masses of ice that move slowly over land.

  • Ice Sheets:

    • Massive glaciers that spread out over land in all directions, formed by the accumulation of snow that compacts over time due to its weight, causing it to flow downhill like a river of ice.

  • Clouds:

    • Formed by collections of water droplets, ice crystals, and dust particles in the atmosphere.

  • Infiltration:

    • The process of water soaking into the soil from the ground level and moving into rocks through cracks and pores.

II. Questions to Know

  • What drives the movement of the water cycle?

    • The Sun and Gravity.

  • Where is groundwater stored?

    • In cracks and tiny pores or spaces between sediment and rock beneath Earth's surface.

  • How does energy from the Sun cause evaporation?

    • It breaks the bonds between water molecules.

  • What are the four main subsystems of Earth?

    • Atmosphere, Hydrosphere, Geosphere, and Biosphere.

III. Additional Information

  • What are the three states of water in Earth's Systems?

    • Liquid (water), Ice (solid), and Water vapor (gas).

  • What happens to temperature at higher altitudes?

    • It decreases.

  • What percentage of Earth's water is saltwater versus freshwater?

    • Approximately 97% saltwater and around 3% freshwater.

  • Where do glaciers currently exist?

    • Areas include Bering glaciers, Alaska; Kutiah glacier, Pakistan; Yosemite Valley, California; The Great Lakes.

IV. Discussion Questions

  • Describe and draw the water cycle:

    • The water cycle illustrates how water moves from the Earth's surface to the atmosphere and back, driven by gravity and energy from the Sun. Evaporation causes liquid water to change to vapor, which then condenses into droplets or ice crystals, forming clouds. Precipitation occurs as water returns to the surface, replenishing groundwater and reservoirs.

  • Freshwater problems caused by biodiversity loss:

    • Loss of organisms critical to water filtration can lead to decreased water quality. Additionally, reliance on wildlife for tourism may harm food availability for human populations.