was recorded, from that point every 10 minutes the water level was recorded. The rate of transpiration was fastest with the heat lamp. This is due to several factors, The first being the water being heated up. As the leaf warms up it gains energy, this energy is transferred to the water inside the leaf as all of the surroundings increase in temperature. This extra energy reduces the amount the water needs to gain to change phases, which leads to more water changing into a gaseous state. Then when the stomata open up more water gas is able to escape, pulling on the water left behind in the cell causing it to do the same thing. This happens all over the plant and leads to the increase in transpiration. Another reason for the transpiration increase is the plant keeping the stomata open allowing more water to evaporate to cool the leaf down, using more water but allowing for the plant to not wilt. A very simple reason that also increases the transpiration rate significantly is because a heat lamp was used light energy was being released and absorbed by the leaf, because the leaf had lots of water it wanted to make as much sugar as possible. So it keeps its stomata open longer to collect more carbon dioxide to make more sugar. The leaf used for this experiment had a total of 120 stomata, there were 32 on the top of the plant and 88 on the bottom. These then allows all the water in the leaf to escape and pull more up the xylem. While this experiment was being conducted, there are several possible sources of error that could have occurred, the first and most prominent error would be the human error factor. For example the number of stomata relies heavily on the accuracy, and with a difference in stomata the rate of transpiration can change quite dramatically. Human error is so prevalent because it can affect all facets of the experiment. Another possible error was the vaseline seal. This is a fairly reliable method but there could still have been water and air escaping through the seam in the leaf. Also as the leaf was in on the plant it was transpiring , then when it was cut it continues to transpire when moven from the water to the potometer. This could have drawn air into some of the xylem rendering them useless and unable to transpire water. All of these factors could have changed the results each in their own way, however none of these errors appeared to be drastically affecting the results. Bibliography: Leopold. "Transpiration - The Water Cycle." , from USGS Water-Science School . N.p., n.d. Web. 29 Mar. 2016. This article covers the effect of transpiration on the water cycle.
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