1. Plant and Soil Science Unit 2 The Carbon Cycle

2. Testing the Gases Plants Emit Question: Will plants emit more Oxygen during the day or night? During the process of respiration, plants in the dark emit carbon dioxide. Plants in the light emit oxygen as a by-product of photosynthesis. Oxygen is a key component of fire, while carbon dioxide puts out fires. Materials: Two sprigs of Elodea or other water plant Two test tubes water two wide-mouthed jars matches or lit candle Methods: 1.Place a sprig of Elodea into each of two test tubes full of water. Be certain that the two sprigs are of equal length. Place a couple of inches of water in each. 2.Place your finger over one test tube so that you do not lose any water, invert it, and place inside one jar. 3.Repeat with the other test tube. Now you have two identical setups. 4.Place one in a dark closet, the other in the sun or under a grow lamp. 5.After a couple of days, some gas should have collected at the upper end of the test tubes. Carefully invert each of the test tubes keeping them closed with your finger. 6.Holding a burning match or candle near each test tube, let the gas escape. The gas from one test tube will glow brightly, while the gas from the other might extinguish the flame.

3. PSS.PP.1

4. PSS.PP.2