Cycling of Matter: Water Cycle


The water cycle describes the movement of water through the environment. Like all cycles, there is no true start or end point, but we can begin our exploration with water located in large bodies of water like oceans,lakes, and rivers. While exploring the water cycle, refer to the diagram below.


Yellowstone_Boiling.jpg1. Liquid water physically changes into a gas during evaporation; this is what happens when you boil water. While some water on earth does continually boil, like at Yellowstone Park, most evaporation occurs in the oceans below the boiling point of water. This occurs more slowly, but given that the oceans cover 70% of the earth, a lot evaporation still occurs.

Condensation.jpg2. Once water vapor or gas enters the atmosphere, it rises and begins to cool. As it cools, it begins to condense or transform back to a liquid from a gas. You have likely witnessed this process on a cold soda can or the cold windows of a building on which small drops of water begin to appear. In the air, condensation occurs on microscopic dust particles (also known as cloud condensation nuclei) that form clouds in the sky. Thus, clouds are in fact not puffs of white air, but large collections of tiny water droplets

Rain_Drops.jpg3. As the water condenses, the drops become larger and heavier. When they become too heavy, they fall as precipitation (rain or snow) due to the force of gravity. It is estimated that only 10% of water that evaporates from large bodies of water like oceans and lakes falls on dry land; the remaining 90% falls back into large bodies of water.

woman-drinking-water.jpg4. Once it lands on the ground, water can take many paths. It may drain into a large body of water or be soaked up into the soil or permeate the ground until it reaches an aquifer. Some water collected in lakes, rivers, or aquifers will be consumed by organisms including ourselves, and returned back to the cycle through our waste. Plants will absorb water from soil, but much of it will be lost from their leaves as it changes from a liquid to a gas in a process known as transpiration; transpiration is similar to evaporation, but only occurs in plants.



Activities: Read the instructions for each activity before beginning them.

  • Activity 3: The Water Cycle
    • Watch the animation, which presents the water cycle in a different way.

  • Activity 4: Generating Quiz Questions
    • Compose 5 quiz questions over the water and nitrogen cycle using the criteria below. If your question is well written, then I will use it on friday's quiz or the six week test. Click on the document to help you write your question. Write your questions on a seperate piece of paper
      • Knowledge question; write a question that simply ask the student to recall a definition of a word
      • Comphrension question: write a question that ask the students to interpret or explain part of the water or nitrogen cycle.
      • Application question: write a question that asks the students to use information from one of the cyles to solve a problem
      • Analysis question: write a question that ask the students compare the one or multiple parts of the water and nitrogren cycle
      • Evaluation question: write a question that ask the students to evaluate the nitrogen or water cycle