How Much Water Is in a Fruit? (cont.)
Session 2: How much liquid does an apple have?
- Ask the class, Do you think other foods contain water? How about an apple? Encourage the students to predict whether apples and other fruits and vegetables contain water. Ask, How could we find out? Could we squeeze an apple?
- Give each group of students an apple and a plastic serrated knife. Direct the students to weigh their apples, record the values and cut their apples into slices vertically (about 1/2 cm in thickness). Have students place the slices between two sheets of paper towel, or skewer the slices along a straw. Then let the apples sit in a warm place for 3–5 days. (The amount of time will vary depending on the temperature; see next step.)
- Have students weigh their sliced apples every day and record the weights (or mass) in grams. When the slices no longer show an appreciable change in weight from one day to the next, they have dried as much as will be possible. Have older students make a graph of the daily weights of their apple slices. Ask, What does the graph tell us about the weight of the apple?
- Have students in each group subtract the final weight of the slices from the starting weight of the apple. The difference will be the weight of the water lost from the apple during the experiment.
Keywords: lesson | life science | health | water | transpiration | evaporation | body | cells | kidney | excretion | dehydrate | dehydration | chromatography |
- Moreno, N., Tharp, B., and Dresden, J. (2011) The Science of Water Teacher’s Guide. Baylor College of Medicine: Houston.
- Illustration © Baylor College of Medicine\M.S. Young.
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My Health My World: National Dissemination
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The Environment as a Context for Opportunities in Schools
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