Observing, Describing, and Identifying Contrails
To enable students to observe contrails, describe them using a common vocabulary, and compare their descriptions with the official contrail types.
Students can observe contrails and identify which of the three contrail types they are observing. The students can sketch the contrails, developing personal and scientific vocabulary, and descriptions of contrails.
Students will be able to identify contrail types using standard contrail type names and descriptions.
If contrail activity is present, allow 2-3 45-minute class periods.
Materials and Tools
Contrail Identification Chart
GLOBE Cloud Chart
Contrail Photo Gallery
Still, video, or digital camera to photograph contrails (optional)
Obtain Contrail ID Chart and other reference materials. The teacher might also take pictures of contrails with a still or digital camera to have for use later.
Basic knowledge of how a cloud forms.
Identifying and Classifying Contrails
Contrails are clouds formed when water vapor condenses and freezes around small particles (aerosols) that exist in aircraft exhaust. That water vapor comes from the air around the plane and the exhaust of the aircraft.
Contrails are "human-induced" clouds since they are formed by water vapor condensing on particles from airplane exhaust. Other types of clouds can be formed by water vapor that condenses on particles which are present in the atmosphere due to many sources, such as from volcanoes or dust storms, not specifically from aircraft exhaust.
Contrail Identification Tips
The GLOBE protocol asks you to identify the three types of contrails:
- Short-lived contrails look like short white lines following along behind the plane, disappearing almost as fast as the airplane goes across the sky.
- Persistent contrails look like long white lines that remain visible after the airplane has disappeared. These contrails are usually one finger- width or smaller.
- Persistent spreading contrails look like long, broad, fuzzy white lines. These contrails remain in the sky for a length of time and are more likely taken for a cirrus cloud. These contrails are wider than one finger-width.
Observing Contrails and Writing Notes
What To Do and How To Do It
- Talk with students about the three types of contrails: Short lived, persistent, and persistent spreading. The first time students observe, let them come up with their own vocabulary, and what they see and encourage them to write all their thoughts and observations down in their Science Journal. Also ask the students to make a sketch of the contrail beside their notes and vocabulary.
- Go outside with the students to an open area with their GLOBE Science Logs to observe contrails. You might have a student check throughout the school day to see if contrails are visible. Students could be organized into two-person teams.
- Students should record the date and time of day in their journal. As students sketch the contrail, encourage them to use as many words as they can to describe the contrail, the wind conditions, and the height of the contrail. Use the one finger rule when observing persistent contrails to talk about their width and to determine whether it is a persistent or persistent spreading contrail.
Emphasize to the students that they should use whatever words seem appropriate to them. Some possible student responses:
Size: wide, narrow, pencil thin, broken, fading, finger width
Description: faint, heavy, lingering, disappearing, long, broad, fuzzy, bending, wavy.
Movement: wind speed, wind direction, area originated
- When students return to the classroom, students can form groups of two pairs to share descriptions and vocabulary. Each group of four students can compile a list of the vocabulary words they used to describe the contrails they observed. These can then be shared with the rest of the class.
- Using the Contrail ID Chart or the Contrail Photo Gallery, students can match their sketches and record the contrail type next to their sketch.
The teacher could also take pictures of contrails over a period of time in case no contrails can be seen during the period of student observations. Students would then have a variety of contrails to write about and discuss.
The students could also take their own photographs of contrails and build a contrail photo wall showing the different types of contrails. Introduce this activity after the students have had an opportunity to observe and identify contrails. It is also possible to videotape contrails to observe the length of time that it takes for them to spread or to decay.
Lesson submitted by Carol Clark, Chapman School, Sheridan, OR, USA