SJB Created 10/12/2011 Revised 7/31/2017
Name:
Botany
Per.
Page 1 of 4
Date:
Task: Virtual Lab to investigate plant transpiration.

Log onto http://www.classzone.com
 Select Biology 2008 textbook
 Under lab section select Virtual Labs
 Select Plant Transpiration
Problem: You moved your favorite houseplant to a new location. You’ve
continued the same watering routine, yet you notice wilting leaves. The plant
gets just as much light in the new location as it did in the old one. What could
be causing the plant’s leaves to wilt?
In this investigation, you will determine how different environmental
conditions affect the rate of
transpiration.
Before exploring the lab:

Click on “Background”
Define Transpiration:
What is the purpose of transpiration?
Where are most of the chloroplasts located?
Where are most of the stomata located?
During the day most of the stomata are ______________ (opened / closed)
During the night most of the stomata are _______________(opened / closed)
What percentage of the plant’s total water supply is used for photosynthesis? ______________
___
SJB Created 10/12/2011 Revised 7/31/2017
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
Botany
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Next, click “Explore”
o Explore the lab to learn what is available for your investigation. You must click on each
item in the checklist. Once you are ready to move on, click PROCEDURE. Note:
clicking procedure will not work until all actual items on the checklist have been clicked
on.
Describe how each item will be used in the experiment.
Potometer –
Pipette –
Airtight seal –
Geranium seedlings –
Fan –
Light –
Spray bottle –
Graph paper –


Next, click “PROCEDURE”
Note: During the procedure you will open up the lab notebook and utilize it but do not print
UNTIL the end of class or lab is completed. Record your predictions and data on paper lab
worksheet.
Predict how each environmental condition, normal, windy, warm and humid, might affect the rate of
transpiration. Rank conditions from lowest to highest with the number 1 being the lowest rate and
the number 4 being the highest rate of transpiration.
Table 1: Predictions
1.
2.
3.
4.
___________________ (Lowest rate)
___________________
___________________
___________________ (Highest rate)
Explain why you ranked the environmental conditions in the order you did.
SJB Created 10/12/2011 Revised 7/31/2017
Botany
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Table 2: Transpiration Amounts with Different Environmental Conditions
Conditions
Normal
0 min
1.0
ml
Windy
1.0
Warm
Humid
10 min
20 min
30 min
ml
ml
ml
ml
ml
ml
ml
1.0
ml
ml
ml
ml
1.0
ml
ml
ml
ml
Table 3: Rate of Transpiration with Different Environmental Conditions
Calculate the rate of transpiration using the formula:
Rate of transpiration = total water loss ml / surface area m2 / 30 min
(This can be done in the simulation)
Condition
Total water loss
Total surface
Total surface
(ml)
area of leaves
area of leaves
(cm2)
(m2)
Normal
Rate of
transpiration
(ml / m2)
Windy
Warm
Humid
Graph 1: Transpiration Rate for Four Environmental Conditions
Environmental Conditions
Normal
Windy
Heat
Humid
Rate of transpiration (ml / m2)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
30
(min)
SJB Created 10/12/2011 Revised 7/31/2017
Botany
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Analysis:
1. Compare your initial predictions to the data results for rates of transpiration under different
environmental conditions.
Transpiration rank
1. Lowest rate →
2.
3.
4. Highest rate →
Initial Prediction (condition)
Data Result (condition)
Discuss whether the data results were consistent with (closely matched) or were inconsistent (did not
match) your predictions including why the data showed the pattern it did (Explain why the actual lowest
result is the lowest and why the actual highest result is the highest).
2. Evaluate: Why was it important to calculate the total surface area of the leaves in addition to the
total water loss in each experimental group?
3. Evaluate: Why was an air-tight seal in the photometer necessary?
4. Hypothesize: Roots play a part in water absorption and transport for plants. Which do you think
plays the most important role in the movement of water through a plant; the absorption of water by
roots OR the evaporation of water from the leaves? Explain the reasoning for your answer.
Describe an experiment you could do to test and support your hypothesis.