Ib Bio Example Transpiration Lab
Nicolette Lindberg
11/30/12
IB Biology 2, Period 1
Transpiration Lab
Background Information- Transpiration is the loss of water from a plant. Plants transpire water out of the stomata in their leaves at a different rate in every environment. The amount of transpiration is affected by the environment, how developed the plant is to not lose as much water, the surface area of the leaves, and how affected the plant is by its environment (Von Bargen). For this experiment, the plant we used was (Viola tricolor subsp. Hortensis), or pansies.
Problem Question- What is the effect of distance from a wind source on how much water a plant transpires?
Manipulated Variable- The manipulated variable in this experiment was the distance of the 5 pansies from the wind source. Each plant was 20 cm farther from the fan than the last, starting at 2o cm distance. This means that the farthest plant was 100 cm away. These distances were selected because we needed a wide range of distances from the fan to measure how much the plants were transpiring with minimal and maximum exposure.
Control Group- Alternating each plant in 2 columns, there were also 5 plastic bags filled with the same amount of water that we watered each plant with. These bags were placed alongside the plants at each distance from the fan. This was to measure if this amount of water without having leaves to transpire, would transpire anyway because of the room environment. It was to measure the validity of the experiment and to determine if a conclusion could be drawn.
Responding Variable- The responding variable was the amount of water that was transpired. We measured this by measuring the mass of each plant and bag each day in grams. We then compared our new measurements to the original ones we took after the initial watering to decide how much water the plant had lost.
Hypothesis- If the plant is closer to the wind source, then the plant will transpire more because the closer to the wind it is, the more dry
11/30/12
IB Biology 2, Period 1
Transpiration Lab
Background Information- Transpiration is the loss of water from a plant. Plants transpire water out of the stomata in their leaves at a different rate in every environment. The amount of transpiration is affected by the environment, how developed the plant is to not lose as much water, the surface area of the leaves, and how affected the plant is by its environment (Von Bargen). For this experiment, the plant we used was (Viola tricolor subsp. Hortensis), or pansies.
Problem Question- What is the effect of distance from a wind source on how much water a plant transpires?
Manipulated Variable- The manipulated variable in this experiment was the distance of the 5 pansies from the wind source. Each plant was 20 cm farther from the fan than the last, starting at 2o cm distance. This means that the farthest plant was 100 cm away. These distances were selected because we needed a wide range of distances from the fan to measure how much the plants were transpiring with minimal and maximum exposure.
Control Group- Alternating each plant in 2 columns, there were also 5 plastic bags filled with the same amount of water that we watered each plant with. These bags were placed alongside the plants at each distance from the fan. This was to measure if this amount of water without having leaves to transpire, would transpire anyway because of the room environment. It was to measure the validity of the experiment and to determine if a conclusion could be drawn.
Responding Variable- The responding variable was the amount of water that was transpired. We measured this by measuring the mass of each plant and bag each day in grams. We then compared our new measurements to the original ones we took after the initial watering to decide how much water the plant had lost.
Hypothesis- If the plant is closer to the wind source, then the plant will transpire more because the closer to the wind it is, the more dry
Cited: Von Bargen, Gretel. "Abiotic Factors on Rate of Water Transport." Skyline High School, Sammamish. 15 Oct. 2012. Lecture.