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Supplies
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These are some materials you may want for this experiment.
- kidney beans from grocery store
- masking tape
- water
- scissors
- soil
- 1/2 gallon mill or juice carton, well rinsed
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To Do
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1. |
Soak kidney beans in lukewarm (not hot) water for 30 to 60 minutes. |
2. |
Bring in a half-gallon milk or juice carton, or obtain one from your instructor. |
3. |
Lay the carton on its side, and cut off the "top" (i.e., one
long side) in one piece:
Figure 1: Removing the Long Side of a Carton
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4. |
Use the point of a pair of scissors or a pencil to punch about 8 evenly
spaced holes in the 'bottom':
Figure 2: Holes Punched in Bottom
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5. |
Fill the carton with potting soil up to 1/2 inch from the top, packing the
soil moderately firmly. |
6. |
Write your group's name and the date on masking tape and place it on the
side of the container. |
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7. |
Plant eight kidney beans (that have been soaked) one-fourth to one-half
inch below the soil, with equidistant spacing. |
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8. |
Water the carton thoroughly and allow to drain onto newspaper or paper towels
(DO NOT DRAIN DIRECTLY INTO THE SINK!). |
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9. |
Lab cleanliness matters. Please do NOT let dirt drain into the sink when
you water your carton. Likewise, please CLEAN all surfaces when done and
put all dirty glassware into a container for dirty glassware. |
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10. |
Place the container on a tray to go under growth lights. (Special growth
lights are desirable but not essential. Good lighting is a must.) |
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11. |
Water the container as often as needed to keep the soil moist but not soaking
wet. |
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12. |
Individually keep detailed notes and drawings of your observations. In three
weeks, summarize your results and write your conclusions about this experiment,
answering the following questions. |
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Questions
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1. |
Did all of your beans grow? If so, you had a germination rate of 100%.
If not, what proportion grew? Calculate the germination rate by dividing
the number of seeds that germinated (e.g., 6) by the total number of seeds
you planted (e.g., 8) and multiplying by 100 to obtain a percentage (e.g.,
75%). What was your germination rate?
for kidney beans: ___________
Typically 75 to 100 % of kidney beans will grow. Calculating the germination
rate is common in scientific studies and is a good opportunity for the students
to practice using percentage in a practical setting.
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2. |
A plant begins life as a tiny seed and grows into a much larger structure,
yet it doesn't eat as animals do. What does it use for constructing itself?
A plant literally builds itself out of thin air. A plant synthesizes
organic molecules, many of which have a 'backbone' of long chains of carbons.
The carbons come from carbon dioxide gas taken by the plant from the air.
These carbons are incorporated first into sugars via photosynthesis and
then into the sugars are combined to form cellulose, starch, and other large
macromolecules.
In addition, a large proportion of the mass of a living plant consists
of water which is taken in through the roots. |
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3. |
What does a plant take in through its roots? What does the plant take
in through its leaves?
Carbon dioxide is taken in through the stomata in the leaves.
A plant needs nitrogen which may be taken in through the roots as
nitrate ions from the soil. When there are nitrogen-fixing bacteria to help,
nitrogen may be obtained from nitrogen gas in the air. Other nutrients and
water are also taken in through the roots.
For your reference, Figure 1 illustrates bean growth in soil:
Figure 1. Bean growth in soil. From Campbell,
N. (1987) Biology . Menlo Park, CA: Benjamin/Cummings Publishing
Co.
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