Students’ age range: 14-16

Topic: Transpiration

 

Description: • The topic is to be introduced during a doublé session. Teacher will place a stalk of celery in red food coloring mixed with wáter about one hour before students begin arriving to class.
• Teacher will explain what xylem vessels are. Students will copy and label a diagram of a xylem vessel into their notebooks under the notes on xylem.
• By now the leaves of the celery that was placed into the food coloring should be red. The teacher will explain to the students that the liquid travel from the beaker to the leaves through xylem vessels.
• Each student will them be given a cross section of that same celery and will need to sketch the cross section, labelling the xylem vessels that have been stained red.

• The teacher will then make a longitudinal section of the remaining portion of the celery so that students can see the xylem vessels stained all the way up the stem.

• In the remaining two sessions, the teacher will provide a definition of transpiration for the students. Together we will set up an experiment to investigate how wind speed and temperature affect the rate of transpiration.

• Before the experiment however, we will do the fishbowl exercise to discuss what students think will happen to transpiration when the temperature increases and when the wind speed increases. This will help with their hypothesis.

• The students and teacher together will then mimic those conditions in the laboratory by designing an experiment that shows how increased temperature and windspeed affect transpiration rate.

• Students will record their results, showing how far up the celery stem the dye traveled for the increased temperature and increased windspeed condition, and compare that to how far the dye traveled under ‘normal’ conditions.

• They will plot their results in a graph using https://nces.ed.gov/nceskids/createAgraph/

• Students will write a detailed conclusión based on their results and graph.