Analogy of Relative Humidity

By Pamela BlackfordMartinsburg High School

1. Place students in small groups. Each group will need beakers, supply of sugar, and 2 spoons. (Have students boil water themselves or have a common container of boiling water.)

2. Record observations in a journal.a. 1st beaker: Measure boiling water and record temperature. Add one teaspoon of sugar at a time to water and stir. Does it all dissolve? Continue to add sugar one teaspoon at a time until sugar no longer dissolves. Record your observations.b. 2nd beaker: Using room temperature water, stir in one teaspoon of sugar at a time until all the sugar no longer dissolves. How many teaspoons of sugar did it hold?c. 3rd Beaker: Repeat steps above using ice cold water. How much sugar did it hold? Measure and record temperature.

3. Students will use their data to make a graph showing the relationship between the amount of sugar dissolved and the temperature of the water.

4. After the graph is completed, provide students with a water temperature. Ask them to use their graph to estimate the amount of sugar that can be dissolved in it.

5. Verify the estimate through experimentation.6. Plot the results on the graph. Ask student to suggest possibilities for

any differences found between estimate and experimental result.7. Repeat steps 4, 5, and 6 with another water temperature.8. Ask students to explain the relationship on their graph.9. Have students look up the definition of relative humidity.10. Ask students to relate their results to develop a simple definition of

relative humidity.

•30 beakers•Sugar•Measuring spoons (10-15)•Hotplates•Graph paper

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