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TABLE OF CONTENTS
Science:
1. The Effect of Center Beam Length on the Strength of A
Cantilever Bridge
2. Effects of Broiler Manure and Litter on a Farm Pond
3. Nitrates In Drinking Water
4. The Effects of Sugar and Caffeine on Typing Speed and
Accuracy
Social Studies:
1. TV or Not TV? That Is The Question
2. Smoking and Smokers: A Survey
Consumerism:
1. Battery Life and Cost Effectiveness
2. Absorbency of Different Types of Sponges
SCIENCE SECTION
TITLE: The Effect of Center Beam Length on the Strength of a
Cantilever Bridge
STUDENT RESEARCHER: Jack Woldtvedt
SCHOOL: Sunburst Elementary School
Sunburst, Montana 59482
GRADE: 6
TEACHER: Shawn Christiaens and Lawrence Fauque
I. STATEMENT OF PURPOSE AND HYPOTHESIS:
People have used bridges for many years to overcome any
obstacles they have found. The earliest bridges were as simple
as a log laid across a stream. Through the years, technology
and materials have been improved to make new bridges that can
withstand thousands of pounds of weight. This experiment was
conducted to test one design of bridges, the cantilever bridge.
A cantilever bridge is a kind of bridge with two outside
supporting beams that hold a center beam. My hypothesis stated
that out of bridges with 10, 20, or 40 cm center beams, the
bridges with the 20 centimeter center beam would support the
most live load.
II. METHODOLOGY:
Sample bridges will be built from pieces of balsa wood that are
2.5 centimeters wide by .5 centimeters thick. Elmers Wood Glue
will be used to hold the balsa pieces together. Ten bridges of
each size; 10 cm, 20 cm, and 40 cm, will be built and tested.
The dead load, or the weight of each bridge, will be determined
using a triple beam balance. Clamps will be used to hold each
bridge to a table edge for testing. Weight will be slowly
added to the bucket device attached to the middle of each
bridge until the bridge breaks and the bucket falls to the
floor. A suitable scale will be used to weigh the bucket with
the weight. This is the live load. All bridges will be tested
in this manner. The efficiency of each bridge will be
calculated by dividing the live load of the bridge by it's dead
load.
III. ANALYSIS OF DATA:
The average efficiency of the bridges in Set A with 10 cm
center beams was 111.72. In Set B, with 20 cm center beams, it
was 139.87. In Set C, with 40 cm center beams, it was 219.27.
Bridge Type Average Average Average
Dead Load (g) Live Load (kg) Efficiency
Set A ( 10 cm) 41.43 4.675 111.720
Set B (20 cm) 32.81 4.575 139.867
Set C (40 cm) 35.46 7.825 219.266
The bridges with the 40 centimeter center beams were able to
hold the most weight, proving that my hypothesis was wrong.
IV. SUMMARY AND CONCLUSION:
In Set A (10 cm center beam), half of the bridges broke in two
places: at one joint between the cantilever and the support,
and where the bridge met the table. The bridges in Set B (20
cm center beam) were more varied. They broke in the middle or
at the two joints and the two spots where the bridge met the
table. The most common breaks in Set C (40 cm center beam)
bridges were in the middle, or in the middle along with one
table joint. The Set A bridges had the lowest efficiency:
between 73.53 and 190.22. The bridges in set B were higher
than set A: between 115.09 and 171.34. Those in set C had the
highest efficiency: between 148.65 and 259.07. The set C
bridges may have been the most efficient, or the strongest,
because the pieces were all longer and the same length and
could distribute the live load better and could bend freely.
Another benefit of the longer center beam may be that there is
just more material to handle the tension and compression forces
of a given load. One factor affecting the balsa wood bridges
was the different hardness of the wood. The difference could
be felt with a fingernail. The softer pieces were more
flexible, but if these were real bridges they could not be used
after they bent to the maximum allowable deflection. The
duration of load was noticed when some bridges held a live load
for a minute before suddenly breaking.
V. APPLICATION:
My experiment will be valuable because in later years, someone
might want to know the best way to build this kind of bridge,
and I would be able to tell them.
TITLE: Effects of Broiler Manure and Litter on a Farm Pond
STUDENT RESEARCHER: Dustin J. Rusert
SCHOOL ADDRESS: Acorn Public School
Rt. 3, Box 450
Mena, Arkansas 71953
GRADE: 7
TEACHER: Linda Whisenhunt
I. STATEMENT OF PURPOSE AND HYPOTHESIS:
I wanted to determine the changes in a farm pond after broiler
manure and litter had been applied to the fields around the
pond. Poultry manure can be a valuable resource or it can be a
pollutant of surface and ground water. The purpose of this
experiment was to establish the chemical changes in a farm pond
where broiler litter had been used on fields around it. My
hypothesis stated that there will be slight pH balance,
ammonia, and nitrate increases without harm to the organisms in
or around the pond.
II. METHODOLOGY:
Water was collected from the test pond (Pond A) before the
litter was applied and weekly thereafter. Water was also
collected from a control pond (Pond B) where litter was not
applied. The water samples were tested for pH balance,
ammonia, and nitrate. In addition, visible plant and animal
life were observed, as well as microorganisms in the pond
water. Results of the sample testing were graphed and compared
to norms.
III. ANALYSIS OF DATA:
The pH level of Pond A increased from 6.8 to 7.0 in the first
two weeks after the broiler litter application. The ammonia
(NH3) level showed no change--it remained at 0 ppm (parts per
million). The nitrate (NO3) level increased from .01 mg/L to
.02 mg/L during the first three weeks.
In Pond B, the ammonia (NH3) level was 0 ppm and the nitrate
(NO3) was .01 mg/L. The pH level remained at 6.8 throughout
the testing period. There were no changes in these variable in
the control pond (Pond B).
IV. SUMMARY AND CONCLUSION:
1. Though the results of pH and nitrates (NO3) for Pond A show
a slight increase, they are still within the normal range.
2. There was no increase in ammonia (NH3) in either pond.
3. No apparent physical or biological changes were seen.
4. Manure management plans need to be established to maintain
safe water quality.
V. APPLICATION:
Poultry manure is a valuable resource when handled and utilized
properly. To protect the environment, it is extremely
important to use good management practices when handling,
storing, and spreading poultry manure. This project shows that
it is a safe fertilizer to use and does not harm the quality of
farm ponds when used properly.
Title: Nitrates in Drinking Water
Student Researcher: Kate Waddick
School: Christ the King & St. Thomas the Apostle School
3210 W. 51st Street
Minneapolis, MN 55410
Grade: 7
Teacher: Mrs. C. Cope
I. Statement of Purpose and Hypothesis:
The objective of this project was to determine nitrate levels
in various drinking waters. My first hypothesis stated that
country untreated well water and city untreated spring water
would contain nitrates. The country well water would probably
have nitrates since according to a professional laboratory
analysis completed in 1993, this water contained 14 parts per
million nitrates. Since the city spring water is in a densely
populated area with much use of fertilizers and run-off, it
might also contain nitrates. My second hypothesis stated that
Minneapolis city treated water from CTK school and the city
purified spring water from Glenwood Inglewood would not have
nitrates. The Minneapolis water would not have nitrates because
it is carefully monitored in a treatment plan, and the Glenwood
Inglewood water would not have nitrates because of the spring
depth and the purifying process as their laboratory analysis
shows.
II. Methodology:
Materials used in this research included: city treated water
from CTK school, city untreated spring water from Lake
Harriet, spring city purified spring water from Glenwood
Inglewood, country untreated well water from a farm in western
Minnesota, Hach Low Range Nitrate Test Kit Model Nl-14,
NitraVer 6 Nitrate Reagent Powder Pillows, NitraVer 3 Nitrite
Reagent Powder Pillows, clippers, two test tubes/color viewing
tubes, and color comparator.
The nitrate test procedure (repeated five times for each type
of water) included: 1. Fill one of the color viewing tube to
the mark with the sample to be tested. Stopper the tube and
shake vigorously. Empty the tube and repeat this procedure.
2. Fill the color viewing tube to the mark with the sample. 3.
Use the clippers to open one NitraVer 6 Nitrate Reagent Powder
Pillow. Add the contents of the pillow to the sample to be
tested. Stopper the tube and shake for three minutes. Allow
the sample to stand undisturbed for an additional 30 seconds.
Unoxidized particles of cadmium metal will remain in the sample
and settle to the bottom of the viewing tube. 4. Pour the
prepared sample into a second color viewing tube carefully so
that the cadmium particles remain in the first tube. 5. Use
the clippers to open one NitriVer 3 Nitrite Reagent Powder
Pillow. Add the contents of the pillow to the sample. Stopper
the tube and shake for 30 seconds. A red color will develop if
nitrate is present. Allow at least 10 minutes, but not more
than 20 minutes, before completing steps 6-8. 6. Insert the
tube of prepared sample into the right top opening of the color
comparator. 7. Rinse the unoxidized cadmium metal from the
color viewing tube used in step 2. Fill to the mark with the
original water sample and place in the left top opening of the
comparator. 8. Hold the comparator up to a light source and
view through the openings in front. Rotate the disc to obtain
a color match. Read the mg/l nitrate nitrogen (N) through the
scale window. To obtain the results as mg/l/L nitrate (NO 3)
multiply the reading on the scale by 4.4.
Three variables may exist. One control variable is the season
of the year the water samples are collected. During the summer
and fall the untreated spring and well waters may contain more
run-off chemicals due to the increased use of fertilizers and
chemicals during the summer on lawns, gardens, and farms.
Since the water samples were taken in November, the nitrate
run-off may not affect water sources as much. This research
could be repeated during different seasons. A second variable-
-a controlled one is the presence in the water samples of other
chemicals that may alter the effectiveness of the test
solutions. I believe I have accounted for this problem by
following the testing directions given by Hach, a professional
water testing company. Another controlled variable is the
temperature of the water which will be maintained at 40 degrees
right after its collection.
III. Analysis of data:
The results of the tests were not what I hypothesized. These
results are the averages of the five tests:
city untreated spring water 0 (ppm)
city purified spring water (Glenwood Inglewood) .0528 (ppm)
city treated water (Minneapolis) .3344 (ppm)
country untreated well water .5104 (ppm)
IV. Summary and Conclusion:
The results of my water testing were not what I hypothesized
for several reasons. One difference is the city untreated
spring water from Lake Harriet spring does not contain
nitrates. The reason may be that the spring is so deep that
nitrate nun-off never enters it or the water is not affected by
run-off in November when I collected my water for testing.
Another difference in is that the city treated water from CTK
and the city spring water from Glenwood Inglewood do contain
some nitrates, but not dangerous amounts. The country
untreated well water does contain nitrates, but the difference
is not as much as I thought it would. A test from 1993 showed
the country water contained dangerous amounts of nitrates, but
now it doesn't. The reason for this change may be that the
water I collected in November didn't have much run-off from
fertilizers and animal waste like it might have had in the
raining, flooding, and warm weather of summer.
V. Application:
I can apply this knowledge to my life in three ways. One way
is that I can help prevent the contamination of city water by
telling people about the hazards of using lawn pesticides and
fertilizers. Also I could write to pesticide and fertilizer
making companies, farmers, and legislators trying to bring
about reduction of contaminants to water. Of greater
importance, I need to start with myself by cutting down on the
use of products that cause nitrate contamination to water.
Title: The Effects of Sugar and Caffeine on Typing Speed and
Accuracy
Student Researcher: Brian Ginsberg
School: Fox Lane Middle School
Bedford, New York
Grade: 7
Teacher: Dr. Sears
I. Statement of Purpose and Hypothesis
I wanted to find out more about the effects of consuming soda
that contains sugar and/or caffeine. Caffeine is a substance
found in coffee, tea, and kola nuts. When it is consumed, it
is a mild stimulant. Sugar is a simple carbohydrate. When it
is consumed, it is used as an energy source. To learn more
about the effects of caffeine and sugar, I studied the typing
speed and accuracy of people who drank soda containing these
substances before typing.
My hypothesis was that because caffeine is a stimulant, it
would cause people to type faster, but that errors would also
increase. I thought sugar as an energy source would also make
people type faster, but not decrease accuracy.
II. Methodology
Ten participants consented to type passages on four different
days. The materials involved in my experiment were: my home
computer and printer, a stopwatch, four passages to be typed by
the participants, and 2 liter bottles of caffeine-free Pepsi,
regular Pepsi, and diet Pepsi. Caffeine-free Pepsi contains
sugar, but no caffeine. Regular Pepsi contains sugar and
caffeine. Diet Pepsi contains caffeine, but no sugar.
Ten people typed four different passages for three minutes on
four different days. For the first trial, the participants did
not drink anything before typing. For the second trial , the
participants drank 8 oz. of caffeine-free Pepsi, 10 minutes
before typing. For the third trial, the participants drank 8
oz. of regular Pepsi, 10 minutes before typing. For the fourth
trial, the participants drank 8 oz. of diet Pepsi, 10 minutes
before typing. It took each participant one minute or less to
drink the sodas.
Each typed passage was evaluated for speed and accuracy. Speed
was measured by counting the number of words typed in three
minutes. Every six letters or spaces equaled a word. Accuracy
was measured by counting the errors.
The variables were the sugar and/or caffeine ingredients of the
sodas. In Trial 1, there was no soda consumed. In Trial 2, a
soda with sugar, but no caffeine, was consumed (caffeine free
Pepsi). In Trial 3, a soda with sugar and caffeine was
consumed (regular Pepsi). In Trial 4, a soda with caffeine,
but no sugar, was consumed (diet Pepsi).
I recorded my data on spreadsheets and graphs. Each
participant was assigned a letter (A-J) for identification.
Each individual's performance was charted and graphed, as well
as the averages of the performances.
III. Analysis of Data
Speed: I compared the typing speed of the passages for Trial I
(no soda) with the typing speed of the passages for Trials 2,
3, and 4 (with sodas). When the participants drank a soda with
sugar, but no caffeine! 70% of the people increased their
speed, 10% stayed the same, and 20% of the people decreased
their speed. When the participants drank a soda with sugar and
caffeine, 70% of the people increased their speed, 10% stayed
the same, and 20% of the people decreased their speed. When
the participants drank a soda with caffeine, but no sugar, 90%
of the people increased their speed, 0% stayed the same, and
10% of the people decreased their speed.
My hypothesis was supported by the data concerning typing
speed. As I had suspected, consuming soda that contains either
sugar or caffeine, or both, increased typing speed. I had
thought that a soda with sugar and caffeine would result in the
greatest number of people typing faster, but the soda with the
caffeine alone produced that outcome.
Accuracy: I compared the accuracy of the passages typed in
Trial 1 (no soda) with the accuracy of the passages typed in
Trials 2, 3, and 4 (with sodas). When the participants drank a
soda with sugar, but no caffeine, 60% of the people increased
their accuracy, 20% stayed the same, and 20% of the people
decreased their accuracy. When the participants drank a soda
with sugar and caffeine, 30% of the people increased their
accuracy, 20% stayed the same, and 50% of the people decreased
their accuracy. When the participants drank a soda with
caffeine, but no sugar, 30% of the people increased their
accuracy, 10% stayed the same, and 60% of the people decreased
their accuracy.
My hypothesis was supported by the data concerning typing
accuracy. I had thought that consuming soda which contains
sugar would not decrease accuracy. This was correct. For 20%
of the people, accuracy stayed the same and for 60% of the
people, accuracy increased. I had also thought that consuming
caffeine would increase errors. This was correct, too.
Accuracy decreased in Trials 3 and 4 when caffeine was
consumed.
IV. Summary and Conclusion
Consuming sugar and/or caffeine before typing had significant
effects on typing performance in this study. Typing speed was
improved generally when soda containing sugar alone, caffeine
alone, or sugar and caffeine together was consumed ten minutes
before typing. Typing accuracy decreased generally when soda
containing caffeine alone or sugar and caffeine together was
consumed ten minutes before typing.
I did not accept or reject my hypothesis based on the trials
performed. I believe that this study was too limited to make
any broad conclusions. One limitation was the number of
participants. A group of only ten people is probably too small
of a group to obtain accurate results. Another limitation was
my inability to control the behavior of all the participants
before they typed the passages each day. I would have liked to
have had each participant type before consuming any food or
beverages, other than themes. Conducting the trials at the
same time each day, if possible, would have also been more
effective. It seems that having the soda as the only variable
in my study was virtually impossible.
V . Application:
If this study could be conducted in a more controlled way and
with a larger number of people, the results might be more
accurate and more useful. The results could be used in the
real world to identify a precise formula for a soda that would
improve typing ability, one that improves both speed and
accuracy. This would be very useful to anyone who types
regularly, such as, secretaries and students. This would mean
that time could be used more efficiently at work, in school,
and at home doing homework.
SOCIAL STUDIES SECTION
TITLE: TV or Not TV? That Is the Question...
(Phase I)
STUDENT RESEARCHER: Lindsay Mata
SCHOOL ADDRESS: Catholic High School
New Iberia, LA 70560
GRADE: 9th grade
TEACHER: Dr. Donald Voorhies
I. STATEMENT OF PURPOSE AND HYPOTHESIS:
Television affects all our lives and not necessarily in a
positive way. Children and adults sit for hours in front of
the television set, often in a zombie-like state, not bothering
to change the channel, even if the program is uninteresting or
has been viewed before. The problem may not be with the
PROGRAMS which are on television, but the television watching
"EXPERIENCE" itself.
The purpose of this study was to find out if sixth grade
students could turn off the television set for five days; if
so, to find out if sixth grade students could benefit from a
"No-T.V." week; and to determine the long-term effects of a "No
T.V.." week.
The hypothesis stated that sixth grade students COULD turn off
the set for five days; that they COULD benefit from the "No-
T.V." week; and that two months later, they would still benefit
from the "No-T.V." week.
II. METHODOLOGY
Sixteen students volunteered to quit television viewing "cold
turkey" from Monday, December 4 at 3:00 p.m. through Friday,
December 8 at 9:00 p.m. This time period was chosen to cover
the after-school hours of 3:00 until 9:00 p.m.
A grid was given to these students. They were to write down
their activities (including TV watching) in order to determine
viewing habits. The same grid was given to sixteen sixth-
graders who volunteered to act as a control group. (This was
called "Pre-No T.V." week).
In the second week, this grid was given only to the study
group. During this time, they did not watch any television and
recorded all activities. (This was called "No-T.V." week).
In the third week, the study group was given this grid in order
to determine if less television was being watched. (This was
called "Post-No T.V." week). A questionnaire was given to
these students at this time.
Two months later, the study group and the control group filled
out the grid to determine the effect of "No-T.V." on long term
viewing habits.
Five categories were studied to compare the average amount of
time a student spent doing various activities between the end
of the school day and bedtime. The categories examined were:
1. Television viewing
2. Studying
3. Reading
4. Playing (indoors and outdoors)
5. Talking with family and friends
IV. RESULTS
The STUDY GROUP, on average, were spending 41% of their after-
school hours in front of the television set. They studied an
average of 1 hour, 8 minutes per day (19%), and read for about
20 minutes (6%). They spent 9% of their time playing, and
talked with family and friends about 30 minutes each day.
The CONTROL GROUP, on average, were spending 39% of their
after-school hours in front of the television set. They
studied an average of 1 hour per day, and read for about 20
minutes per day. These figures are consistent with the study
group.
During the "No-T.V." week, the STUDY GROUP doubled their amount
of study time (from 19% to 39%) and also doubled their time
spent reading to 40 minutes per day. The students' play time
and interaction time also doubled to 60 minutes per day.
The results from "Post-No T.V." week showed the STUDY GROUP
dropped their TV watching time from 41% to 26%. The time spent
reading, playing and talking with family and friends improved
over "Pre-No T.V." week, although all had dropped a little from
"No-T.V." week.
Two months later, the STUDY GROUP was still watching less
television than they had been initially. The time spent
reading and playing had also increased. Study and interacting
time remained the same. The CONTROL GROUP however, was still
watching the same amount of television as they had been (about
2.16 hours every afternoon).
The questionnaire showed that 77% of the STUDY GROUP missed TV
LESS than they thought they would. 77% had not been bored.
62% indicated they would TRY to watch less TV. Finally, 85%
were better able to concentrate on their homework.
IV. SUMMARY AND CONCLUSION
Sixteen sixth-graders WERE willing to turn off the TV set for
five days; five days without TV DID increase their study time,
reading and play time, as well as time spent interacting with
family and friends; and two months later, students were
watching less television, reading and playing more, and
studying and interacting the same as during the "Pre-No T.V."
week.
V. APPLICATION
Television is here to stay. But, there are benefits to turning
it off for a little while, say for twenty-four hours or five
days. Unplugging the television set can improve family
relationships, schoolwork, and play and reading habits.
TITLE: Smoking and Smokers
STUDENT RESEARCHER: Dana Beuhler
SCHOOL: Mandeville Middle School
Mandeville, Louisiana
GRADE: 6
TEACHER: Ellen Marino, M.Ed.
I. STATEMENT OF PURPOSE AND HYPOTHESIS:
I wanted to do my scientific research project on sixth grade
students' feelings about smoking, smokers, and cigarettes. My
first hypothesis stated that a majority of sixth grade students
attending Mandeville Middle School will have immediate family
members that smoke. My second hypothesis stated that all of
the students will have a negative attitude toward smoking.
II. METHODOLOGY:
I stated my purpose, reviewed the literature, and developed my
hypothesis. Then I developed my questionnaire and drew a
random sample population of thirteen sixth grade students from
MMS. Next, I administered the questionnaires and scored them.
I analyzed the data, wrote my summary and conclusion, and
applied my findings to the real world.
III. ANALYSIS OF DATA:
Twelve of the thirteen surveys I handed out were returned.
Only three students surveyed had immediate family members that
smoke. A majority of the students believe they have learned
enough to make a confident decision about smoking. Ten
students said that they think they will never take up smoking.
Nine students agree that smoke from smoking areas gets to them
when sitting in non-smoking areas. All twelve of the students
surveyed believe that smoking is harmful to one's health, that
it is not cool, and that cigarette companies try to advertise
their products in any way possible. Fifty percent of the
students (six students) had friends that smoke. A majority of
the students agree that second-hand smoke makes them feel sick,
it smells bad, and it makes them cough. One stated that he/she
was allergic to smoke and another said you could get cancer
because of what others do.
IV. SUMMARY AND CONCLUSION:
Out of the thirteen questionnaires I handed out, twelve were
returned. A majority of the people surveyed did not have
immediate family members that smoke. All of the students,
however, had negative attitudes toward smoking. Therefore, I
rejected my first hypothesis which stated that a majority of
sixth grade students attending Mandeville Middle School will
have immediate family members that smoke. I accepted my second
hypothesis which stated that all of the students will have a
negative attitude toward smoking.
V. APPLICATION:
Now that I have completed my scientific research project, I can
share my results with science teachers, D.A.R.E. officers, and
cigarette companies.
CONSUMERISM SECTION
TITLE: Battery Life and Cost Effectiveness
STUDENT RESEARCHERS: Brian Lande and Katie Lande
SCHOOL: WindyCreek Home School
Wynnewood, Pennsylvania
GRADES: 7 and 5
TEACHER: Nancy Lande
I. STATEMENT OF PURPOSE AND HYPOTHESIS:
We use so many batteries and they are so expensive to keep
replacing that we wanted to find out which batteries we could
get our money's worth from the best. We wanted to see if the
battery commercials were true about which were the longest
lasting batteries. Our hypothesis stated that the batteries
would all last about the same amount of time or within a 10%
difference range (for either the alkaline or non-alkaline types
of batteries). In other words, we thought they would all be
about the same, but that some of them just had fancier
commercials and better known names.
II. METHODOLOGY:
First, we decided to limit our trials to D batteries only. We
picked a flashlight to be our method of testing, since we
especially use a lot of flashlight batteries in our home. We
had to design a way to test the batteries and determine exactly
how long each type would last. We designed a complete circuit
inside of a shoebox with a lid. The source of the circuit
began with a flashlight that used two D batteries and a fresh
flashlight bulb (for each trial). The flashlight shone across
the box onto a photoelectric cell. Since a photoelectric cell
shuts OFF the circuits when there is light, we had to reverse
the effect by using a relay to turn ON the circuit when the
flashlight was lighting the box. We needed a transformer to
change 110 volts of the photoelectric cell down to 12 volts.
After many failures of what seemed like a correct circuit, we
finally realized that we needed a load of electricity from a
lamp to draw more power in order to activate the photoelectric
cell, so we plugged a lamp into the system between the relay
and the transformer. (If the batteries and the flashlight were
on, then the lamp would go off.) We connected the transformer
to a 12 volt hour meter that would measure the amount of time
that the flashlight stayed on. As soon as the batteries ran
down, the flashlight would turn off, the photoelectric cell
would close the circuit to the hour meter and the hour meter
would shut down and turn on the lamp. When the lamp went on we
would know when the batteries had ran down. For the five
trials of each battery brand we recorded the amount of time
that each set of two D batteries ran, the cost of each pair of
batteries, and the expiration dates (which were all about
January of 1998). We recorded that we changed the flashlight
bulb and where we bought the batteries. We tried to buy the
batteries at different stores so that they wouldn't all be from
the same shipment. We ran three trials of each battery but
then decided that it was too small of a sample and decided it
would be best to run five trials, which we did. We then
computed the range of the time length and the price range of
each battery brand. We averaged the time, the price and the
price per hour for each brand of battery. We kept records of
all our data.
III. ANALYSIS:
As we were doing our experiment, we realized that there was an
issue about the length of time that someone would need to use a
battery and that cost or price per hour alone wasn't enough to
make a decision about buying batteries. Battery cost
effectiveness had to be based on the length of time that
someone needs to use batteries. There are times when you go
camping and need long lasting batteries and times when you
might just be using toys at home when you want just the
cheapest batteries. So, there isn't just one best way to chose
a battery--it all depends on how you want to USE them. Our
analysis showed that there was often a very wide range of time
variance within the SAME brand of battery--even much more than
10%!
Average Average Price
Life (Hr.) Price Per Hour
Energizer Alk. 24.72 $3.18 $ .13
Duracel Alk. 26.96 $3.19 $ .12
Radio Shack Alk. 22.24 $2.99 $ .13
True Value Alk. 23.08 $2.15 $ .09
Panasonic Alk. 21.42 $2.59 $ .12
Mallory Reg. 8.32 $1.25 $ .15
Everready Reg. 5.76 $1.55 $ .27
Radio Shack Reg 12.32 $ .69 $ .06
IV. SUMMARY AND CONCLUSION:
Not only was there greater than a 10% difference within each
brand of battery (except for the Radio Shack Enercell which was
less than 10%), but there was greater than 10% variance in time
variance between the different battery brands. Therefore, we
conclude that our hypothesis was incorrect and that there is
more than a 10% time difference in the battery life of D
batteries. In our limited sampling, the statistical variances
were so small that we weren't sure that they were significant,
especially between the alkaline brands. The one battery with
the best price per hour was the Radio Shack Enercel (non-
alkaline) at $.06 and it also lasted about one half as long as
the longest running alkaline batteries. Of the alkaline
batteries, the True Value was the best price per hour at $.09.
The alkaline battery that lasted the longest on average was
Duracel with an average of 26.96 hours (though one trial of
Energizer lasted the longest at 28.9). Everready (non-
alkaline) cost the most of any of the batteries and lasted the
shortest amount of time.
V. APPLICATION:
The results of our trials lead us to recommend that people buy
Radio Shack Enercell non-alkaline batteries for toys and
batteries to be used around the house. They cost the least per
hour and last about half as long as the expensive alkaline
batteries. Perhaps the cost is so low because they don't spend
a lot of money advertising their batteries as the best buy.
But if you need your batteries to last a long time and don't
want to carry around spare ones, we recommend the Duracell
alkaline batteries as the longest lasting, though the True
Value lasted almost as long and was less expensive. Perhaps
advertising adds a great deal to the cost of batteries, and
Radio Shack benefits because it sells only their own brand and
they don't need to advertise. The Energizer may keep going and
going (even though Duracel may go even longer) but the Radio
Shack Enercel keeps going and going at by far the least amount
of money per hour.
Title: Absorbency of Different Types of Sponges
Student Researcher: Jennifer Frustino
School: Kenmore Middle School
Kenmore, New York
Grade: 8
Teacher: Evelyn Swarts
1. Statement of Purpose and Hypothesis:
I wanted to find out more about the absorbency of different
types of sponges. Absorbency is the degree to which a substance
is absorbent, or soaks up or takes in. I wanted to find out if
the amount of water a sponge absorbs is affected by the
material the sponge is made of (natural vs. synthetic) and the
size of the sponge's pores (large vs. medium vs. small). My
first hypothesis stated that a natural sponge will absorb more
water than a synthetic one. My second hypothesis stated that a
synthetic sponge with the smallest sized pores will absorb the
most water.
11. Methodology:
First, I wrote my statement of purpose, researched the
literature on sponges and absorbency, and developed a
hypothesis. The materials needed for my investigation were:
one natural sponge, three synthetic sponges (one with small
pores, one with medium pores, and one with large pores), a
ruler, scissors, two equal sized cups, water, liquid measuring
cup, forceps, and a timer. To test natural vs. synthetic
sponges, I measured one 3.5 cm cube from the natural sponge,
and poured 250 ml of room temperature water into one of the
cups. I placed the natural sponge cube into the cup and timed
it for 3 minutes. When the 3 minutes passed, I grasped the
corner of the sponge cube with the forceps and lifted it out of
the water. After allowing all of the excess water to drip, I
squeezed the saturated sponge over the other dry cup until no
more water could be released. I repeated this exact procedure
two more times, for a total of three trials. The manipulated
variable was the type of sponge. The responding variable was
the amount of water each sponge absorbed. The variable held
constant was the size and shape of the sponges.
Next, I measured one 3.5 cm cube from the synthetic sponge and
repeated the same exact procedure for the natural sponge with
the synthetic sponge.
For my next test, I cut three more 3.5 cm sponge cubes. One
with small pores, one with medium pores, and one with large
pores. I repeated the procedure above with these three
sponges. I had three trials for this procedure, also. The
manipulated variable was the pore size of the sponges. The
responding variable was the amount of water each sponge
absorbed. The variable held constant was the size and shape of
the sponge cubes.
III. Analysis of Data:
In The first trial testing natural vs. synthetic sponges, the
natural sponge absorbed 28 ml of water. The synthetic sponge
absorbed 43 ml of water. In the second trial, the natural
sponge absorbed 25 ml of water. The synthetic sponge absorbed
39 ml of water. In the third trial, the natural sponge
absorbed 27 ml of water. The synthetic sponge absorbed 45 ml
of water. On average, the natural sponge absorbed 27 ml of
water and the synthetic sponge absorbed 42 ml of water. The
synthetic sponge absorbed more water.
In the first trial for testing pore size, the large pored
sponge absorbed 43 ml of water. The medium pored sponge
absorbed 14 ml of water, and the small pored sponge absorbed 31
ml of water. In the second trial, the large pored sponge
absorbed 39 ml of water, the medium, 12 ml of water, and the
small 35 ml of water. In the third trial, the large pored
sponge absorbed 45 ml of water, the medium pored sponge
absorbed 14 ml of water, and the small pored sponge absorbed 37
ml of water. On average, the large pored sponge absorbed 42 ml
of water. The medium pored sponge absorbed 13 ml of water.
The small pored sponge absorbed 34 ml of water. The large
pored sponge absorbed the most water, then the small pored
sponge, and the least absorbent sponge was the medium sized
pores sponge.
IV. Summary and Conclusion:
The amount of water a sponge absorbs is affected by the
differences in natural and synthetic sponges. A synthetic
sponge absorbs more water than a natural one. For this test,
my first hypothesis is rejected. I also found that a sponge
with the largest sized pores absorbed the most water, then the
small sized pores, and the least absorbent sponge was the one
with medium sized pores. My second hypothesis is also rejected
for this test.
V. Application:
This information is applicable to life. Sponges are good for
cleaning and absorbing. It is good to know that a synthetic
sponge is more absorbent than a natural one. Natural sponges
can be used in other ways like sponge painting and shower
sponges. More absorbent synthetic sponges can be used to clean
up spills and wash the car. I also found through this
investigation that good science needs repetition (for example 3
trials per sponge) and measurement.
© 1995 John I. Swang, Ph.D.