Which tastes can a blindfolded student detect? Use a drinking straw "dropper" and put small amounts of different solutions on the tongue. Try strong cold coffee, weak solutions of sugar or salt, as well as lemon juice or diluted vinegar. Rinse your mouth out with water between each sample.
Look at plants that we use. Each group researches and presents about one plant's characteristics, adaptations, uses, habitat and impact on the local community. They could include coffee, tea, cocoa, oil seed rape, cotton, flax, rubber, pine and oak.
Students measure their pulse rate before and after a glass of water; repeat using drinks like ground coffee, cocoa, tea and Coca-Cola and de-caffeinated drinks; and compare the effects on heart rate.
Caffeine is a plant alkaloid. Research the sources of other alkaloids (such as atropine, cocaine and quinine) and their effects on the body. Consider the genetic manipulation of coffee and the trials in French Guiana (see the article in New Scientist on May 29, 2005 or visit www.newscientist.comchannellifegm-food)