Hello, we are Group B of S2-03. The big idea of our experiment is on the rate of transpiration of celery. To be more specific, we are experimenting on the the rate of transpiration of celery (distance travelled by the red dye vertically) and how the speed of wind can affect it. The reason why we chose this project is because we were curious on how the effect of wind speed can cause the rate of transpiration to differ. We chose wind speed as our independent variable because in the transpiration of a plant, the factors of transpiration are temperature of the air, light, and humidity. If we had chosen temperature in air, it will be very hard to measure because it is very hard to control humidity. If we had chosen light, there would be two variables, light and the heat so it would be harder to manage. Thus, we chose wind speed as our independent variable. We believe that as the speed of wind increases, so will the rate of transpiration.
“Most of the time, plants get their water from the ground. This means it has to transport the water from its roots up and throughout the rest of the plant. How does it do this? Water moves through the plant by means of capillary action.” (Staining Science: Capillary Action of Dyed Water in Plants. (n.d.). Retrieved January 20, 2016, from http://www.scientificamerican.com/article/bring-science-home-capillary-action-plant/)
“Capillary action occurs because water is sticky, thanks to the forces of cohesion (water molecules like to stay close together) and adhesion (water molecules are attracted and stick to other substances). Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus which turns upward. The surface tension acts to hold the surface intact. Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules. The height to which capillary action will take water in a uniform circular tube is limited by surface tension and, of course, gravity.” (Capillary action. (n.d.). Retrieved January 20, 2016, from http://water.usgs.gov/edu/capilaryaction.html)
But the plant does not only depend on capillary action, it also depends on transpiration, transpiration does the main job of water absorption in a plant stem.
1.1 Research Questions
What is transpiration?
What is humidity?
What is water vapour concentration gradient?
Will the speed of wind cause the rate of transpiration to differ?
How much difference will the speed of wind make?
Hypothesis: As the speed of wind increases, so will the rate of transpiration, causing the red dye to vertically move up the celery stalk faster.
Our independent variables are the 3 different fan speeds. Our dependant variable would then be the distance travelled by the red dye vertically up the celery.
- Distance between the celery and fan
- Length of Celery Stalk
- Number of leaves
- Concentration of red dye
- Location of experiment