http://www.phschool.com/science/
biology_place/labbench/lab9/xylem.
html
Daily Warm-up Monday, April 21st
What processes help move water up a tree?
HW:
-Read 42.4
Turn in:
-Nothing
AP Lab 11: Transpiration
Transpiration
• Evaporation of water from aerial parts of
plants (not roots)
• Relies on hydrogen bonding of water
molecules and the processes of cohesion and
adhesion
What causes different rates of
transpiration?
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Number of leaves
Number of stomata
Size of the leaf
Presence of cuticle
Light supply
Temperature
Relative humidity
Wind
Water supply
Adaptations for Reducing Water Loss
• Leaf structure
• Different photosynthesis: CAM plants
• Cuticle
Today’s Lab
• Working in groups
• Each group will receive one type of plant but
must subject the plants to 4 conditions
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Wind (fan)
Light (lamp)
Room temperature (away from any drafts)
Humidity (put within a bag that is misted with water)
• Will record each day’s mass in table at the
beginning of class for remainder of week
Steps
• Receive plant type, break into 4 separate plants
• Place plant’s roots in bag of water with 20-25 mL
of water. Tie the bag tightly so that no air is able
to escape. Weigh plant and record in table. Each
person needs to make a table and record the
group’s data.
• Set in proper conditions: fan, room temperature,
humidity (bag placed over rest of plant), and light
Daily Warm-up Monday, April 28th
What type of graph might you use to display the
change in % mass for each of the five days?
HW:
-Transpiration lab due 5/10
Turn in:
-Nothing
Lab Notebook
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Title: Transpiration Lab
Brief introduction
Hypothesis- inquiry lab worksheet
Methods (no materials required)
Table
Graph- line graph- one line for each treatment showing
change in % mass each day
• Results- what did you find?
• Conclusion- why did you find what you did. Make sure
to explain findings and say whether or not hypothesis
is SUPPORTED. Include potential errors and future
research.
• Questions from transpiration question sheet