|Question: What side of a plant leaf takes in gases?
|Hypothesis: Ten (10) students say the top of the
leaf takes in gases because when rain and watering cans water plants it
comes from above and hits the top of the plant leaves first. Ten (10)
say the bottom of the leaf takes in gases because after observing the
leaves from each plant the bottom of the leaves were more veiny and the
skin of the bottom leaves seemed thinner. The top of the plant leaf
had a thicker, waxy covering and it looked like water would be hard to
get through it.
|Materials: Two varieties of plants
|Procedure: Coat the top of four leaves from each plant with a heavy layer of Vaseline.
Coat the underside of four leaves from each plant with a heavy layer of Vaseline.
Observe the leaves daily for one week.
Is there any difference in the two sets of leaves?
|Results: Three of the four leaves that had
Vaseline on the underside, died. Only one leaf with vaseline on the top
died. Therefore, we believe that plant leaves take in gases from the
bottom, not the top, of each leaf.
|Why: Openings on the underside of plant leaves called stomata allow gases to move into and out of the leaves. The vaseline plugged the openings and the leaf was not able to receive the necessary carbon dioxide gas or eliminate excess oxygen gas.|