TITLE:
A Pine Cone Mystery
QUESTION:
How does water affect pine cone scales?
RESEARCH:
The scales on a pine cone close inward when they are exposed to
water. When the cells at the base of each scale are saturated with
water, the resulting pressure causes the scales of the pine cone to
close. This process keeps the seeds from leaving the pine cone when it
is wet. If the seeds were to fall from the pine cone when they were
wet, then they would drop close to the mother tree and have to
compete with it for water and nutrients from the soil. The seeds do
much better when the pine cone is open on dry, windy days. The wind
blows through the pine cone and carries the seeds to a more ideal
location to grow.
Sources:
"Gone With the Wind Pine Seed Dispersal." AgEd. N.p.. Web. 11 Nov 2012.
<http://aged.uga.edu/browseable_folders/ClassStartersMentalSetFadctsFiguresIdeas
/Gone_With_The_Wind_Pine_Seed_Dispersal.doc>.
Durham, Tim Dr.. "Pine Cone Opening Mechanism." Newton Ask A Scientist. Argone National
Lab U.S. Dept. of Energy, 01 Jun 2012. Web. 11 Nov 2012.
<http://www.newton.dep.anl.gov/askasci/bot00/bot00947.htm>.
Reeves, Walter. "Pine Cones - Why Do They Close Up?." Walter Reeves.Com. The Simple
Gardener, Inc., Web. 11 Nov 2012. <http://www.walterreeves.com/gardening-q-anda/pine-cones-why-do-they-close-up/>.
VARIABLES:
Independent Variable: Water
Dependent Variable: Appearance of the pine cones scales
Control Variables: Same type of pine cones
Same size pine cones
Same type of containers
Same location of containers
Same amount of time pine cones are in the
container.
HYPOTHESIS:
If I place one pine cone in water and one pine cone in air, then the pine
cone in water will close its scales, because the cells at the bottom of
each scale become saturated causing water pressure to build up and
force the scales to move inward (close), thus protecting the seeds
located inside the scales.
MATERIALS:
(2) Pine cones (from the same pine tree) that are the same size and
with open scales
(2) 1,000 ml containers
800 ml of tap water
1,000 ml plastic beaker
PROCEDURE
1)
Obtain two pine cones that are the same size and have open
scales and are from the same pine tree.
2)
Place the two 1,000 ml containers side-by-side on a flat
surface,
3)
Fill one of the containers with 800 ml of water using the 1,000
ml plastic beaker.
4)
Simultaneously (both at the same time), put one of the pine
cones in the 1,000 ml container filled with water and put the
other pine cone in the empty 1,000 ml container.
5)
Repeat steps 1 – 4 two more times so that there are three
trials of the experiment.
6)
Record observations for all three trials at 9:00 a.m. the next
day.
RESULTS:
THE BELOW PHOTOGRAPHS WERE TAKEN AT 9:00 A.M. THE DAY AFTER THE
EXPERIMENT WAS SET UP.
Trial #1 Water
Trial #2 Water
Trial # 3 Water
All of the scales on the pine cones in the water closed.
The water turned a pale yellow color.
The pine cones floated at the surface of the water.
Trial #1 Air
Trial #2 Air
All of the scales on the pine cones in the air stayed open.
Trial #3 Air
CONCLUSION:
1) Tell whether your hypothesis is correct or incorrect, and support your
decision by using specific examples from the data collected.
My hypothesis was correct. The results from all three trials showed
that the scales on the pine cones closed when place in water.
2) Describe any difficulties with the experiment?
It was difficult to find pine cones that were all the same size and from
the same tree.
3) Explain any reason to disbelieve your results?
I was unable to monitor the pine cones the entire length of the
experiment. It is possible that another variable could have been
introduced to the experiment. For example, someone could have poked
at the pine cones when I was not watching.
4) Write about any research you’ve done to clarify your results.
My results showed that the pine cones floated in water. I remembered
reading about why things float in class, so I went to my Weather and
Water Resources book, and it stated on page 30 that “materials less
dense than water float in water.” That means the pine cone is less
dense than the water.
Source:
Weather and Water Reources. Nashua : Delta Education, 2004. 30. Print.
5) Do the results of your experiment cause you to have any further
questions that could be answered through conducting another
experiment?
Water is 100% humidity. Will the pine cone close at a lesser percent
of humidity?