WATER LOSS IN PLANTS

PROBLEM: Do plants lose water through their leaves?

RESEARCH: Look up transpiration in a biology textbook. In your own words, write at least two paragraphs about transpiration.

HYPOTHESIS: Based on your research, do you think water will come out of the leaves of the plant?

MATERIALS:

one growing plant (you may use a plant in your garden)

2 clear plastic bags (like a sandwich bag or vegetable bag from the grocery store

tape

PROCEDURE:

1. Place one sandwich bag over one leaf.

2. Secure the bag on the stem with the tape.

3. Place the plant in the sunlight for two or three hours. (If you are using a plant from your garden, be sure to choose one that will be in the sunlight for at least three hours.)

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4. Fill the second bag with air without blowing into the bag.

5. Secure the bag the same way you did the first bag.

6. Place the second bag near the plant you are using to test your hypothesis.

DATA: Make a data table to record your observations. Make observations at least 5 times at half hour intervals.

CONCLUSION: This is not optional. You must explain what you learned by doing this activity.

Remember that you must answer the question you asked in your original problem statement.

NOTE: BE SURE TO HAVE YOUR PARENT OR GUARDIAN SIGNS YOUR WORK. PARENTS: YOUR SIGNATURE SHOWS YOUR STUDENT HAS DONE THE WORK.

TEACHER SECTION:

POSSIBLE HYPOTHESIS: Students should discuss possibility that leaves will or will not lose water from the leaves.

POSSIBLE CONCLUSION Students should discuss how their observations support the idea that plants lose water through their leaves.

POSSIBLE RESEARCH PARAGRAPH Plants absorb water from the soil through their roots. This water moves up the stem to the leaves where 90 percent is lost through the pores of the leaves (stomata). Some trees lose as much as 15,000 pounds (6,810 kg) of water within a 12 hour period. This loss of water through the stomata is called transpiration.

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Judy Schneider

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