Classification of Clouds
Suggested Grade Level/Time:
- Grades 9 - 12. One block / 90 minutes.
Objectives:
- Students will:
- Investigate the conventions for classifying and naming cloud types.
- Use standard nomenclature to identify cloud images by type
National Standards and the following Virginia SOLs:
- ES.4.2 - The student will investigate and understand the characteristics of the Earth including water in all three states.
- ES.13.1 - The student will investigate and understand that energy transfer between the Sun, Earth, and the Earth's atmosphere drives weather and climate on Earth. Key concepts include observation and collection of weather data.
Vocabulary:
- Cirrus, Cirrostratus, Cirrocumulus, Cumulus, Cumulonimbus, Altocumulus, Altostratus, Nimbostratus, Stratocumulus, Stratus, Fog, and Contrails
Class of Activity
Applications to Technology and Society:
- Part of the preparation of students for participation in the S'COOL program, that is, providing "ground truth' for satellite cloud data is to familiarize students with an example of a conventional system of identifying clouds.
- This activity additionally serves as a vehicle for required teacher use of technology in the classroom, including laser disks and /or Internet.
Materials:
- Cloud Chart (provided with S'COOL materials; any poster showing pictures of the various cloud types, with names, is appropriate). See the S'COOL: On-Line Cloud Chart.
- Laser disk: "Understanding Earth: The Atmosphere" (or other sources of cloud images; see "cloud chart," above.) See also Cloud Features and Phenomena for an excellent source of cloud images, organized by type.
- Textbook: Earth Science or Atmospheric Science
Procedure
- Before running this activity, students should be familiar with calculations for determining condensation heights, based on ideal convective cooling models (this assumes a drop of 1 degree C per 100 m height increase, and a like drop in dew point of 0.2 degrees C. Note: See lesson plan called "A Lab for Determining Cloud Height." This background will lead to the logical idea of classifying clouds by height of base (low, mid-level, high), which is the system used for S'COOL reporting.
- Students should be given access to the cloud chart, and also textbook diagram(s) showing the various cloud types and their names; a brief introduction to standard cloud nomenclature by the instructor is appropriate.
- Show students a "slide show" or like progression of cloud images, either from the "Atmosphere" laser disk or from some Internet source (NASA's image gallery is a good place to look). Using the poster and textbook as references, students should independently attempt to identify the various clouds shown, in terms of the standard names. One or two examples for guided practice are a good idea, if enough cloud images are on hand.
- Tally the number of different answers for each image, and the number of students who chose each answer; compare the various answers given with the cloud identification given for the laser disk slide or web image.
- Run through the slides again, this time asking students to estimate a height based on the cloud's appearance: Low, Mid-level, or High. Contrast precision and accuracy for this method with those obtained in step 3.
Conclusion:
- This activity obviously serves as a preparation for S'COOL participation, familiarizing students with cloud identification. It serves an additional purpose if the "extension" possibilities are explored.
Teacher's Notes:
- Evaluation: This is an introduction to cloud nomenclature; it is not intended as a stand-alone graded activity. It is assumed that students' knowledge of cloud types will be tested at a later time.
- Extension Activity: The qualitative (actually, I prefer the term"vague" in this case) nature of the standard cloud nomenclature system is the source of great student anguish, in cases where they are expected to distinguish between "altostratus," "stratocumulus," "nimbostratus" clouds, and the like. Clearly, a more quantitative system, or at least one with clearer criteria, would be preferable. Students can be asked to evolve a more "user" friendly" (or at least less confusing) system of cloud nomenclature. Parallels can be drawn with the English standard measurement system, which has been largely replaced (except in the United States and one or two other places) with the far less arbitrarily-based Metric (SI) system - a system devised relatively recently (compared to the English system) simply because the older system needed revision or replacement.
Lesson Plan developed E. Goldman, Tabb High School, York County Schools, Virginia, USA, for NASA's S'COOL Project.
