Evaporation

Topic(s): 
Water
Guiding Questions
Are there differences in rates of evaporation in shaded, forested areas versus full sun, open field areas? If there are differences in rates of evaporation, what could be some possible causes or factors affecting these differences?
Overview

Evaporation occurs when sunlight or other sources of heat energy, causes water to turn from a liquid state to a gaseous state. This process occurs all across the globe in the worlds’ oceans, lakes, and rivers. When enough gaseous water, or water vapor, rises and condenses in the atmosphere, precipitation occurs. This process drives the worlds’ weather patterns.
In this study, you will place a predetermined amount of water in “evaporation pans”. These pans will be placed in an full sunlight area (open field) and a shaded area (forest) in order to compare rates of evaporation under different conditions. You can then ask questions about the importance of trees and plants in keeping moisture in the environment.

Time
2 Class periods
Setting
Schoolyard
Materials

Initial setup:

  • Evaporation pans
  • Measuring cup for water
  • Gallon jugs with water

After collection:

  • Graduated cylinder
  • Calculator
Procedure

Decide what question you want to ask
1. Write down the question about evaporation that you would like to address. Also, formulate a hypothesis based upon your question.
2. Survey your schoolyard, pick your sampling sites, and develop methods to collect your data.

Choose your sampling sites
1. Choose two areas that are in sharp contrast to one another in terms of sunlight exposure. This will allow you to generate questions and discussions about the importance of trees and the shade they provide in retaining water.

Measure the amount of water
1. Use your graduated cylinder or measuring cup to determine the amount of water. Do this in the field to prevent spilling.

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