In my spreadsheet, I’ll record the
voltage drop across the CdS cell and
the distance of the light source.
Distance will then be converted into
intensity by the formula, 1/(distance
* distance). In the next column of
the spreadsheet, I’ll convert intensity
into relative intensity by dividing
each intensity by the intensity at the
greatest distance. Then, I’ll graph the
CdS voltage and relative intensity.
I can generate an equation from
the graph and use it to analyze the
changes in brightness as a function
of altitude during an experiment. In a
future column, I will explain how to
create an equation from discrete
values such as these and how to
Near Space Seeds Project (NSSP)
NUTS & VOLTS
My NS mission of 21 March 2004
carried four sets of seeds to an altitude of
85,140 feet. I want to share these seeds
with elementary school students as part of
a science experiment. I hope this will be a
long term project, where students plant the
seeds, keeping each group of plants isolated
from the other groups.
After the plants go to seed, students
will collect the seeds, document the group
to which they belong, and return them for
another flight into NS. After the mission,
the seeds will be returned to the students
for planting and seed harvesting. Perhaps,
over many generations, variations between
the groups due to the differences in their
exposure will begin to show up.
Table 2 explains the difference
between the seed groups in each set.
Note: This first set of exterior
exposed seeds was stored in a plastic bag
suspended outside the NS craft.
If you’re a teacher who is interested in
being a part of this experiment and you can
carry out the following procedure, please
contact me at the Email address in the
About the Author box. I will send one set
of seeds to the first four teachers to contact
me. There is no charge for participating.
More seeds will be launched in future
flights, so there will be more opportunities.
1. Find a location with sunlight and air for
Note: Remember, you need to plant
three groups of seeds and there needs to
be enough space between the groups to
prevent them from cross-pollinating plants
from a different group.
2. Prepare planters for the seeds and
document your materials.
Note: You will need to use identical
procedures for future generations of seeds.
3. Water and feed the groups identically.
Note: The only difference should be
the seeds’ level of NS exposure.
4. Document plant growth in each group.
Note: Suggested characteristics to
document include (but are not limited to)
A. Number of days to germination.
B. Percentage of seeds that germinate.
C. The average height of plants over time.
D. Average number of leaves per plant.
E. Number of days until flowers form.
F. Average number of flowers per plant.
G. Number of seeds produced per plant.
If the class is mathematically inclined,
they can also calculate the standard
deviation for each measurement. Also note
that a digital camera comes in handy.
5. Erect a barrier between the seeds.
Note: It’s critical that plants from
different groups don’t pollinate each other.
6. Harvest seeds from several plants in
each group and prepare them for another
flight into NS.
Note: It would be best if the seeds are
placed inside a clean, dry test tube and covered
with a small cotton ball. The test tube is
then covered with a stopper containing
a hole. The hole lets air out of the test
tube during the flight without popping the
stopper off. The cotton is to keep the seeds
from spilling during the flight, especially
during the rough descent and landing.
7. Label each test tube with the group that
the seeds belong to (control, interior, or
* Note: Write the group name on a
small piece of masking tape and stick it to
the test tube. For added security, cover the
writing on the tape with clear tape. This will
keep the name from rubbing off during
handling. Place the name near the top of
the test tube where it cannot protect the
exterior seeds from exposure to UV
during the mission.
8. Through Email, arrange for the seeds to
go up on the next available flight.
Note: If you send the seeds through
the mail, carefully pack them in a cardboard
box for shipping. The test tubes should be
packed so that they cannot bang against
each other and break.
9. Each test tube of seeds will be placed
where they were on previous flights.
Note: After recovery, the seeds will
be returned for planting and the procedure
repeats over again.
3% sea level
( 30. 5 mb)
- 30 degrees
3% sea level
( 30. 5 mb)
- 70 degrees
On a final note, you can purchase your
own seeds for a flight into NS. Please
contact me first, however, so I can schedule
a flight for your seeds. It would be best if
classes from the same school sent their
seeds in single test tubes and divided up
the seeds after they are returned. Sharing
room in the same test tube will simplify