7.1.3
Investigating Transpiration
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Investigating Transpiration Rate
The rate of transpiration can be influenced by a number of factors. An experiment can be set up using a potometer to estimate transpiration rate. The steps involved are:

1) Assemble the potometer
- A potometer is a piece of equipment that is used to estimate the volume of water taken up by a plant in a given time.
- The potometer is filled with water and a cutting of a shoot is placed inside.
- The shoot must be cut and placed into the potometer while underwater to ensure no air enters the xylem.

2) Form the air bubble
- Remove the end of the capillary tube from the water beaker.
- Wait for a bubble of air to form in the capillary tube.
- Place the capillary tube back into the water.
- The air bubble is used to record the volume of water used by the shoot.

3) Record bubble movement
- Mark the starting position of the air bubble.
- Use a stopwatch to record the distance moved by the air bubble in a given time period.

4) Calculate transpiration rate
- Calculate the rate of movement of the bubble per hour.
- The rate of bubble movement is equal to the transpiration rate.

5) Change the variable
- The experiment can be repeated by changing a different variable each time (e.g. temperature or light).
- It is important to only change one variable at one time and to keep all other conditions constant.
- Changing one variable allows the effects of an environmental factor on transpiration rate to be compared.
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes1.1.2Introduction to Eukaryotic & Prokaryotic Cells1.1.3Ultrastructure of Eukaryotic Cells1.1.4Ultrastructure of Eukaryotic Cells 21.1.5Ultrastructure of Eukaryotic Cells 31.1.6Prokaryotic Cells1.1.7Viruses1.1.8End of Topic Test - Cell Structure1.1.9Exam-Style Question - Microscopes1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones15.1.2Receptors15.1.3Taste15.1.4Reflexes15.1.5Action Potentials15.1.6Saltatory Conduction15.1.7Synapses15.1.8Cholinergic Synnapses15.1.9Neuromuscular Junction15.1.10Skeletal Muscle15.1.11Sliding Filament Theory Contraction15.1.12Sliding Filament Theory Contraction 215.1.13Menstruation15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
Jump to other topics
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes1.1.2Introduction to Eukaryotic & Prokaryotic Cells1.1.3Ultrastructure of Eukaryotic Cells1.1.4Ultrastructure of Eukaryotic Cells 21.1.5Ultrastructure of Eukaryotic Cells 31.1.6Prokaryotic Cells1.1.7Viruses1.1.8End of Topic Test - Cell Structure1.1.9Exam-Style Question - Microscopes1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones15.1.2Receptors15.1.3Taste15.1.4Reflexes15.1.5Action Potentials15.1.6Saltatory Conduction15.1.7Synapses15.1.8Cholinergic Synnapses15.1.9Neuromuscular Junction15.1.10Skeletal Muscle15.1.11Sliding Filament Theory Contraction15.1.12Sliding Filament Theory Contraction 215.1.13Menstruation15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
Practice questions on Investigating Transpiration
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- 3How is the transpiration rate calculated?Multiple choice
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