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Trial 2 - Paper leaf versus living leaf

1. Think about a large jar, like those that contain mayonnaise. Moist soil is put in. A healthy green plant is placed carefully in the soil. The lid is screwed on tightly. The plant receives sunlight and darkness in equal amounts. The temperature of the jar is maintained at 23 degrees Celsius or 75 degrees Fahrenheit. How long do you think the plant will live in the jar?

   

   A. It will die quickly.

   B. A few days.

   C. A few weeks.

   D. A month or more.

   Select one of the answers and explain your reasoning. Share and discuss you thoughts with other members of your group. After a few minutes, join others in your class that selected the same answer. Discuss your reasoning with this new group until you come up with a shared reasoning that you can use to defend you choice. Share your reasoning with the entire class.

   
   
2. The process of photosynthesis supplies food for plants by combining together several elements in and around the leaves. The stomata are the way in which this transfer of elements can occur from the surrounding air in to the plant. Identify some of the elements that are transferred by the leaves.
   
   

3. If one were to look at the anatomy of a leaf, it would be easy to see how these materials are brought to the leaf so that they can form food. The stoma is the way in which this transfer of ingredients can occur, transferring the CO₂ (carbon dioxide), H₂O (water) and light from the surrounding atmosphere in to the plant.

   ***Missing Image***
   High-powered microscopic view of a leaf stoma
   Source: http://www.microscopy-uk.org.uk/mag/articles/stomata.html

   Let's investigate the transfer of water through the stomata (plural of stoma). Select a healthy potted plant with broad leaves.

4. Use one of the leaves to trace a pattern of the leaf on construction paper.Be careful to not tear the leaf from the plant.

   

5. Use scissors to cut out the pattern of the leaf.

6. Think about the differences you would see if you bagged both the leaf pattern and a live leaf with a relative humidity sensor. Would one of the bags show signs of moisture more than the other? Record your thoughts below.
   
   

7. Refer to Technical Hints to connect the relative humidity sensor. A relative humidity sensor will measure the amount of moisture in the air.

8. Place the leaf pattern in a re-sealable bag with a relative humidity sensor. Make sure the slots on the relative humidity sensor are not blocked and are open to the air in the bag by standing the sensor on one end. Seal the bag and start the sensor. Refer to Technical Hints to record a series of measurements. Stop recording after 2 hours.

   

   
   
9. Place your plant near a window. Bag a live leaf while it is still on the plant with a relative humidity sensor. Make sure the slots on the relative humidity sensor are not blocked and are open to the air in the bag by standing the sensor on one end. Seal the bag and start the sensor. Refer to Technical Hints to record a series of measurements. Stop recording after 2 hours.