Limp Salad?


This comes to me compliments of our resident A&F, Anatomy and Fizziology, teacher, Cindy Johnson.
Contact her at Cindy's email for other ideas in bio and help on these.

Even after you have explained and they have "learned" osmosis, they will be tricked by this quick demo. At the beginning of class, place a fresh lettuce leaf in fresh water and another in salt water. This also works VERY well with celery syalks standing in glasses of fresh and salt water. Ask the students for their prediction (hypothesis) of what will happen. Most students will guess that the salt will keep the veggies crisp. Au contraire, my furry little friend...

The higher concentration of water INSIDE the veggie forces water OUT, thus making it limp and disgusting. Ugh! No wonder I never ate my greens. Except green beer on that holiest of holy days, St. Pat's day, of course.


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