Dew Point

Grade Level:

• Grade 4

Objectives:

• The student will investigate conditions causing saturation and measure the dew point of the atmosphere performing simple experiments.

Estimated Time for Completing Activity:

• 1 class period.

Virginia SOLs:

• 4.6 - The student will investigate and understand how weather conditions and phenomena occur and can be predicted. Key concepts include weather factors (temperature, air pressure, fronts, formation and type of clouds, and storms); and meteorological tools (barometer, hygrometer, anemometer, rain gauge, and thermometer).

National Science Standards:

• Standard D - Objectives in the Sky: The sun, moon, stars, clouds, birds, and airplanes all have properties, locations, and movements that can be observed and described.

Vocabulary:

• saturation, dew, dew point

Prerequisites:

• evaporation, condensation, use of thermometer

Class of Activity:

• Exploratory

Materials Needed:

• Each group will receive: a sponge, spoon, tray or pie tin, metal can (like soup or vegetable cans), thermometer, worksheet for each student, water, ice.

Teaching Procedures:

1. Before the class, gather all the materials for each group (activity works well with two in a group).
2. Pass out worksheets and have students read through top section and briefly discuss.
3. Allow them to investigate the meaning of saturation and fill in the data they gather. Have them continue the activity by measuring the dew point. Have them fill in the sentences as they complete the activities and make sure their partner agrees with the answers. This section on saturation also goes along well with the precipitation lesson where the clouds become saturated (or full of water drops) and fall to the ground as rain.
4. Continue activity to find and measure the dew point.

Conclusion/Summary:

• Go over the worksheet being sure students understand key terms.
  Answers to the practice quiz.

  The dew point is the temperature where moisture in the air condenses. As the sun's heat evaporates moisture from the air, the water changes to an invisible gas called water vapor. When the temperature cools down, the water vapor condenses, or turns the gas back to a liquid. These drops of water are called dew and form on plants, windows, and cars.

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Lesson Plan submitted by Karen Hooker, Williamsburg James City County Public Schools, Williamsburg, Virginia, USA, for NASA's S'COOL Project.

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