|Grade Level: Grade 6-9|
|Estimated Time for Completing Activity: One 50-minute class period|
|Learning Outcomes: |
The student will be able to
- explain the meaning of dew point temperature
- use the dew point temperature to estimate the height of a cloud-base
|National Standards: |
- Science Content D: Earth and Space Science
|Virginia Standards of Learning: |
- Science 6.1 : The student will demonstrate an understanding of scientific reasoning, logic, and the nature of science by planning and conducting investigations.
- Science 6.3 : The student will investigate and understand the role of solar energy in driving most natural processes within the atmosphere, the hydrosphere, and on Earth's surface.
- Science 6.6 : The student will investigate and understand the properties of air and the structure and dynamics of Earth's atmosphere.
- Science PS.7 : The student will investigate and understand the characteristics of sound waves.
- Science ES.12 : The student will investigate and understand that energy transfer between the sun and Earth and its atmosphere drives weather and climate on Earth.
- Math 6.17 : The student will identify and extend geometric and arithmetic sequences.
- Math 8.14 : The student will make connections between any two representations (tables, graphs, words, and rules) of a given relationship.
- Understanding of the processes of evaporation and condensation
- Understanding of Earth's Water Cycle.
- empty aluminum can
- stirring rod
- ice cube
- thermometer (C scale)
|Lesson Links: |
|Background: Humid air in the atmosphere moves according to strict physical laws. This lab takes advantage of those laws to use measurements at the surface and infer the altitude of the cloud base. The method calculates the Lifting Condensation Level, which is the level at which condensation - formation of water droplets - would occur if a parcel of air near the surface is lifted upwards. The method will only work for a limited number of low-level clouds, but may be useful in deciding between low- and mid-level clouds. |
- Record air temperature with thermometer.
- Add a cube of ice to the can half full of water. Insert the thermometer and stir with stirring rod. Note the temperature as soon as mist appears.
- Remove the ice and stir. Record temperature as soon as mist disappears.
- Calculate average of #2 and #3. This is the dew point temperature. Record dew point temperature.
- Determine the altitude of the clouds be following these steps:
- Record the temperature and dew point temperature at ground level.
- For every 100 meters in altitude the temperature drops one degree C and the dewpoint drops 0.2 degree C.
- Construct a chart like the one started here. (This is an example. These numbers are not real!!!)
- Continue until the numbers match. At that point draw a cloud.
Ask students to draw an illustration of the cloud type with height labeled on the picture.
|Altitude (meters) ||Temperature (deg C)|| Dew Point (deg C)|
|400 || 18 || 18 = Cloud|
|300 || 19|| 18.2|
|200 || 20 || 18.4|
|100 || 21 || 18.6|
|Ground || 22|| 18.8|
- Ask students to take a picture of the sky or the clouds present on the day/time that the experiment is completed, then write a paragraph that explains if and/or how the estimation can be done for those clouds.
|Teacher Notes: |
- The students may need a demonstration on one day, then allowed to conduct the investigation on the same or different day. It is more meaningful if there are low clouds in the sky on the day of the investigation, since the estimate works primarily for lower clouds.
|Assessment: This lesson provides opportunity for formative assessment and class discussion. The teacher may desire to use a previously developed rubric if a more formal assessment is desired.|
|Reference: Lesson developed by the S'COOL team.|