Lesson 5: Clouds and the Water Cycle

Getting Started

Where does the water from humidity go? It creates clouds, fog, and precipitation, all as part of the water cycle. Different kinds of clouds tell you different things about the approaching weather.

Weather journal: In your weather journal, record today's temperature, air pressure, precipitation, wind speed and direction, relative humidity, and wind chill or heat index information, if applicable. You will fill in other information later in the lesson.

Stuff You Need

  • Eyewitness Weather by Brian Cosgrove (revised edition)
  • colored pencils
  • scissors

Ideas to Think About

  • How are clouds connected to the water cycle?
  • How does my local water cycle affect the weather in my area?

Things to Know

  • The water cycle has five main components: water storage, evaporation (and transpiration), condensation, precipitation, and runoff (and infiltration).
  • Water storage refers to water stored both in the atmosphere (as water vapor) and on land (in oceans, lakes, groundwater, ice, etc.).
  • Evaporation occurs when water turns into water vapor (a gas). Water evaporates from large bodies of water, moist soil, or even from ice and snow.
  • Transpiration is a type of evaporation where water vapor is released from plants' leaves.
  • Condensation occurs when water vapor becomes liquid. Water condenses out of the atmosphere as dew, fog, and clouds.
  • Precipitation is water released from clouds and falls to the ground as rain, snow, hail, or sleet.
  • Runoff is water (such as snow melt and rain) running off land and returning to water storage.
  • Infiltration is a form of runoff; it is the process of precipitation being absorbed into the ground as groundwater and for use by plants.
  • Warm air can hold more water vapor than cooler air can. As air warmed by the Earth rises in a low-pressure area, it cools and cannot hold as much water. This "extra" water condenses to form clouds.
  • Stratus clouds are the lowest level of clouds; they are usually layered sheets of clouds.
  • Cumulus clouds are puffy, rounded clouds usually found in the middle cloud layer.
  • Cirrus clouds are the highest level of clouds and form in streaks or wisps.
  • The ten main cloud types are cirrus, cirrostratus, cirrocumulus, cumulus, altocumulus, stratocumulus, cumulonimbus, stratus, altostratus, and nimbostratus.


  • Discuss and determine how cloud cover is affected by predictable patterns of weather. (S)
  • Describe and analyze the formation of various types of clouds and discuss their relation to weather systems. (S)
  • Investigate the water cycle, including the processes of evaporation, condensation, precipitation, and runoff. (S)

Introducing the Lesson

Today your child will look at where the water from humidity goes. He will learn why clouds form when water vapor is pushed out of cooler air. He will also explore the ten types of clouds and what they tell us about the approaching weather.
Reading and Questions
Materials: Eyewitness Weather by Brian Cosgrove (revised edition)
Watch "The Making of a Cloud" at the following link, and then read pages 24-29 in Eyewitness Weather by Brian Cosgrove. Answer the following questions:
Web Link

  1. In order for water vapor to condense (turn from a gas to a liquid), water molecules need a surface to collect on. Clouds are created when water vapor condenses around tiny particles in the air. What are these particles called? Give two examples of these particles from the video.
    The particles are called condensation nuclei. The video mentions ice, air pollution, sea salt, and dust.
  2. What are thermals and how do they create clouds?
    Thermals are pockets of air near the surface of the Earth that become warmed by the Sun and rise. They carry water vapor with them, which cools and condenses as it rises. This creates clouds.
  3. How are clouds similar to steam and the breath of mammals?
    Both are created by warm air meeting cold air that makes the water vapor condense.