To teach students that marijuana causes a decrease in reaction time.
Ask a student to come up to the front of the class. Hold up a pencil vertically by the eraser. Tell the student to put his or her hand just below the pencil in a position so pointer finger and thumb are extended. Tell the student to prepare to catch the pencil with the thumb and pointer finger. Drop it between the thumb and finger and see if the student can catch it (Usually he or she is successful).
Now have the student soak his or her hand in the ice water for a few minutes. Repeat the same activity. It should be obvious that the first performance was better than the second. Reaction time was better the first time.
Explain to the students that people who use marijuana experience decreased reaction time even when their body parts are warm.
One pencil, One bucket of ice water
There is no teacher tip available for this lesson plan.