E-Database of Science, March, 1999

The National Student Research Center

E-Journal of Student Research: Science

Volume 7, Number 2, March, 1999

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The National Student Research Center is dedicated to promoting student research and the use of the scientific method in all subject areas across the curriculum, especially science and math.

For more information contact:

John I. Swang, Ph.D.

Founder/Director

National Student Research Center

2024 Livingston Street

Mandeville, Louisiana 70448

U.S.A.

E-Mail: nsrcmms@communique.net

http://youth.net/nsrc/nsrc.html

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TABLE OF CONTENTS

1. Do Different SPF's Make A Difference When Using Same Brand Sunblock? Does Price Affect The Way Sunblock Works?
2. Viscosity
3. The Growing Of Plants Under Different Colored Lights
4. How Humidity Affects The Growth Of Cherries
5. The Flammability Of Household Fabrics
6. Which Household Items Lubricate Metal The Best?
7. Root Development
8. The Decomposition Of Different Foods In Different Environments
9. The Effect Of pH On The Life Span Of A Tadpole
10. Mouthwash And Bacteria

Title:  Do Different SPF's Make A Difference When Using Same
        Brand Sunblock?  Does Price Affect The Way Sunblock
        Works? 

Student Researcher:  Laura Barkin 
School:  Edgemont Jr/Sr.  High School 
         White Oak Lane 
         Scarsdale New York 10583
Grade:  7 
Teacher:  Ms.  Russo

I.  Statement of Purpose and Hypothesis: 

I wanted to know if SPF matters when you buy sun block.  For 
example, does a CVS brand 30 sunblock work better than a CVS 
brand 15 sunblock?  I also wanted to know if higher priced 
sunblock works better than lower priced sunblock of the same 
SPF?  My hypothesis was that the higher the SPF the better it 
would protect and that higher priced sun block would work better 
than lower priced.  

II.  Methodology: 

For the first part of my project, I bought four types of CVS 
brand sunblock.  Each of these sunblocks had a different SPF.  
The different SPF's were 30, 15, 8, and 4.  I also bought a pack 
of developing paper at a local photography store and 4 clear 
plastic report folders.  I then got some distilled water and a 
dish pan.  I asked my science teacher for sodium thiosulfate.  
The first thing I did was divide the report folder in 4 equal 
squares using masking tape.  I then labeled each sun block 1, 2, 
3, or 4.  I labeled each square 1, 2, 3, or 4.  I then applied 
the numbered sunblock to the appropriate square.  I put the same 
amount of sunblock on each square making it as even as possible.  
After I put the sunblock on, I dimmed the lights very low.  I 
carefully took out a piece of developing paper, making sure to 
close the case afterwards to keep the light away from the other 
sheets.  I put the developing paper, glossy side up, inside the 
report.  I then quickly took it outside on the driveway where it 
was very sunny.  I left it there for exactly 5 minutes.  While 
it was in the sun I made the mixture of the sodium thiosulfate 
and distilled water in the dish pan.  When the 5 minutes was up 
I brought the report folder back inside to the semi-darkened 
room.  There I carefully took out the developing paper from the 
report folder and layed it glossy side down in the mixture for 
three seconds.  Then I immediately rinsed it with cold water and 
let it dry for 15 minutes.  When it was dry I observed it.  
For the second part of my experiment I did the exact same thing 
except I used the sun blocks that varied in price, but had the 
same SPF.  

My controlled variables was that I used the same amount of light, 
same dish pan, and the same mixture of sodium thiosulfate.  My 
manipulated variables were the different sunblocks with the 
different SPF's or the differently priced sunblock.  The responding 
variable were my results.  

III.   Analysis of Data: 

On the developing paper, the sunblock which allowed the least 
amount of sun to penetrate, turned the whitest.  When I observed 
the data from my first experiment I was very surprised at what I 
saw.  I noticed that the SPF 30 sunblock was darker than the SPF 
4 sunblock.  This was very strange because I surely thought that 
30 was better than 4.  What I then saw was that in some places I 
had put more sunblock on the number 4 square than others, also 
the places where I had put more sunblock were the lightest and 
where I hadn't put much on it was the darkest.  For trial one 
SPF 4 was the best, then SPF 8, then SPF 15, and last SPF 30.  
For trial two, SPF 8 was the best, then SPF 4, then SPF 15, and 
last SPF 30.  

For the second part of the project my results were not as 
strange, but were not what I expected.  For trial one, "Bain de 
Soliel", which was the highest priced, worked the best.  "Banana 
Boat", which was the least expensive, was second.  "Bio Sun", 
the second highest priced was next, and then the second lowest 
priced, "Neutrogena" came in last.  

IV.   Summary and Conclusion: 

As I said before, I was very surprised when I saw the results of 
both tests.  They did not agree with my hypothesis at all.  For 
the first experiment, it seemed to me that it did not matter 
what SPF you used, but how much you put on of each one.  That is 
why I think SPF is irrelevant, if you put a lot of sunblock on 
and keep reapplying it.  

For my second experiment, I think it mattered how thick the 
sunblock was.  Bain de Soliel was the thickest and then Banana 
Boat.  But Neutrogena which came last was not thick and was very 
light.  So, for my second experiment, I feel price does not 
matter, but thickness does.  

V.   Application: 

I can apply the results of this experiment in many ways to my 
life now.  I now know I can use any type of sunblock and the SPF 
will not matter.  I will just have to remember to put a lot on 
and keep reapplying it.  I also know that if I buy a sunblock 
and it has a thin texture to find another brand.  These results 
can be critical for many people.  With the depletion of our 
ozone layer, skin cancer is a common problem.  People need to be 
aware of the SPF confusion and be informed about thick 
application of sunblock to prevent the damaging effects of the 
sun. 


Title:  Viscosity

Student Researcher:  Caitlin Dieck
School:  Fox Lane Middle School
         RT 172
         Bedford, New York 10506 
Grade:  6 
Teacher:  Carolynn Sears, Ph. D. 

I.  Statement of Purpose

The purpose of my experiment was to find out if the name brand 
or temperature of olive oil effects its viscosity.  My first 
hypothesis stated that the Pope Delicato and Candoni (Extra 
Virgin) will be most viscous.  My second hypothesis stated that 
cold olive oil will be more viscous than warmer olive oil.   

II.  Methodology

I designed two experiments to test my hypotheses.  The materials 
I needed for the experiments were a stopwatch, a paper clip, a 
measuring cup, 4 types of olive oil, a microwave, a magnet, and 
a bottle. 

The first experiment is called the Pour Test.  My mom would set 
the bottle on the ramp to let the olive oil pour into the 
measuring cup.  I would be next to her timing how long it took 
to pour to the 1 cup line.  We would do this with all four 
brands/types at the different temperatures.  We would pour each 
oil three times and then average the times.  

The controlled variable is the size of the measuring cup.  The 
manipulated variables are the temperature of the olive oil and 
the different brands of olive oil.  The dependent variable is 
the time it takes for 1 cup of olive oil to pour. 

The second test was called the Paper Clip Test.  I would take 
the paperclip, put it in the olive oil, then take the magnet and 
pull the paperclip right above the olive oil, and then release 
the paperclip.  My mom would stand next to me and time how long 
it took to touch the bottom of the bottle.  We would do this in 
all the brands/types in the different temperatures.  We would 
drop the paper clip three times to get an average.  

The controlled variables were the size of the paper clip and the 
measuring cup, and how the paper clip is dropped.  The 
manipulated variables were the temperature of the olive oils and 
the different brands.  The dependent variable is the time for 
the paper clip to drop through the olive oil. 

III.  Data Analysis

The data showed that the extra virgin olive oils (purer olive 
oils) were generally more viscous and that cold olive oil was 
generally more viscous. 
 
IV.   Conclusion

In my conclusion, the Candoni (Extra Virgin) and Pope (Extra 
Virgin) are most viscous.  Candoni (Extra Virgin) was most 
expensive, then came Pope (Extra Virgin).  Out of the 
temperatures, the cold olive oils were most viscous in most of 
my data.  In my hypothesis, I thought that the Pope Delicato and 
Candoni (Extra Virgin) were going to be most viscous, but I was 
wrong. 

V.  Application

From doing this experiment, I found that Candoni (Extra Virgin) 
and Pope (Extra Virgin) are most viscous and that cold olive oil 
is more viscous than hot olive oil.  I have also learned more 
about graphing and organizing my data.  I learned a lot.  One 
thing I will remember is to let the olive oil become room 
temperature before pouring it for cooking. 

 
Title:  The Growing Of Plants Under Different Colored Lights

Student Researcher:  Thomas McConville
School Address:  Fox Lane Middle School
                 Route 172
                 Bedford New York 10506
Grade:  6 
Teacher:  Dr.  Sears and Mr.  Karlsson

I.  Statement of Purpose and Hypothesis

I wanted to find out whether the color of the light source has 
an effect on the growth of plants.  My hypothesis was that 
regular white light from a regular light bulb would be the most 
effective light source on the plant.  The other two colors in my 
experiment were red from one end of the spectrum and green from 
the other end of the spectrum. 

II.  Methodology

I purchased radish seeds because they grow very quickly.  Then I 
gathered my materials which were: three light bulbs, (red, 
green, and white), 20 seeds, four pots exactly the same size, 
potting soil, three lamps.  I placed one plant in the sun 
(natural light), and this was my control.  The different colored 
lights were the independent variable.  The controlled variables 
were: the same brand of lamps, the distance of the lights from 
the plants I grew, the temperature and amount of water, the 
amount of soil, the pot size, the depth that the seeds were 
planted.  The plants were placed in a closet with the same 
temperature, and each plant received the same amount of light 
(same watt bulb).  The dependent variable was the amount that 
the plants grew under the different colored lights.  Once I 
gathered all of my materials, I planted the seeds the same depth 
in the same size pot and the same amount, and kind of potting 
soil.  I watered with the same amount and temperature of water 
to begin this experiment.  I watered my plants every other day.  
I placed the three pots in a dark closet, with the different 
colored lights above them at the same distance.  I turned on the 
light sources for twelve hours each day.  I watched every day to 
see which plant grew the fastest.  I measured the length of the 
stem and took observations of this experiment.  I also took 
pictures of this experiment. 

III.  Analysis of Data

My hypothesis proved to be correct: the white (or clear bulb) 
proved to be the best light source.  The next tallest was the 
plant under the red bulb.  The next tallest was the plant under 
the green bulb and the last was the plant growing in natural 
light.  However, the plants in the natural light were the 
healthiest and had the largest leaves. 

IV.  Summary and Conclusion

I found out that clear or white light grew the tallest plants.  
Their leaves were also full.  This probably happened because 
there was twelve hours of continuous light per day.  Although 
the red and green plants were the next tallest, they were not as 
healthy looking.  The plants under the natural light were not as 
tall, but had very full leaves and looked the healthiest.  My 
hypothesis was correct. 

V.  Application

Although natural light may not grow plants as fast, they will 
turn out to be healthier.  My second choice for growing plants 
would be a regular white light left on for at least 12 hours per 
day. 


Title:  How Humidity Affects The Growth Of Cherries

Student Name:  Michael Kistenmacher 
School Address:  Edgemont Jr./Sr. High School 
                 White Oak Lane 
                 Scarsdale, NY 10583 
Grade:  7 
Teacher:  Ms. Russo

I.  Statement and Purpose and Hypothesis: 

My hypothesis states that if cherry branches are covered in a 
transparent plastic bag and are allowed to accumulate humidity, 
the percentage of blossoms that become cherries will be higher 
on the covered branches than on the uncovered branches.

II.  Methodology: 

I selected, in May 1998, four branches of a cherry tree in my 
garden.  Over the first and third branch, I put a transparent 
plastic bag.  I counted the blossoms on each of the branches and 
also recorded the percentage of blossoms that became cherries.  
In addition, I recorded the high and low temperature every day.  
I recorded these temperatures in order to know if there was a 
frost or excessive heat, that could have affected the growth of 
the cherries.  Sometimes I took pictures of the branches. Inside 
of the plastic bag there were always water drops and that 
explains the high humidity inside.  Sometimes I had to remove 
water from the plastic because it was too humid inside.  If I 
would have left the water there, mold could be produced inside.

III.  Analysis of Data: 

I recorded the data every day and wrote them on a data table.  
From that data, I generated two charts of the percentage of the 
blossoms that turned into cherries and another one just for the 
amount of the cherries.  I also checked the temperature in order 
to know if there was excessive heat or frost that could affect 
the cherries.  The maximum temperature was 34.4 C and the low 
was 2 C. Therefore there was no negative temperature effect on 
the cherries.

IV.  Summary and Conclusion:

The data show that between 10 and 2S percent of all the blossoms 
turned into cherries in the first weeks.  The uncovered blossoms 
had totally different results then the covered blossoms.  The 
second branch (uncovered) grew fast, but the fourth (uncovered) 
branch lost it's blossoms.  The blossoms of the branches one and 
three (covered) grew fast and did not loose cherries as fast as 
the fourth branch did.  But, in the end, only 1 to 5 percent of 
the cherries remained.  There was no advantage for the covered 
branches.  I conclude that my hypothesis is wrong.

V.  Application: 

My results show that, in 1998, a cherry farmer did not have to 
put a plastic bag around the branches of a cherry tree, because 
there was no advantage in doing so, in the New York area.  
Because there could be different temperatures in other states or 
in other years, the effect of the plastic bag could help to 
prevent frost damage.  Also, in very dry climates, the humidity 
might be useful for the growth of cherries.

 
Title:  The Flammability Of Household Fabrics

Student Researcher:  Andrew Laub
School Address:  Edgemont Jr./Sr. High School
                 White Oak Lane 
                 Scarsdale, New York 10583
Grade:  7
Teacher:  Ms. Russo

I.  Statement of Purpose and Hypothesis:

The purpose of my project is to find out more about the 
flammability of household fabrics used in the home, and maybe 
find a relationship between the size of the fabric, the length 
of time that it was exposed to fire, and the length of time that 
it takes to burn.  Since I picked out a lot of different kinds 
of fabric to test, I wasn't sure of what to expect.  My 
hypothesis states that most of the fabric would burn (or melt) 
rather quickly.

II.  Methodology:

I tested my hypothesis through a cycle of using two different 
sizes of the same fabric, tested twice.  

My controlled variables were the unit measurement of time (in 
seconds), and the way the fabric was lighted (by using a match 
held directly to the fabric which was folded over to help get 
the fire going on all sides).  This was done for every single 
piece of cloth tested.  The responding variable was the time the 
fabric took to burn.  The manipulated variables were the kinds 
of fabrics used and  the two different sizes of the fabric (4 
in. squares and 16 in. squares). 

I used 7 different kinds of fabric: Nylon, Satin Taffeta, Terry 
Cloth, Brushed T-Shirt Cotton, Broad Cloth, Linen, and Rayon.  
Both the Nylon and the Terry Cloth weren't fully consumed by the 
flame at any time in the experiment, I made a special graph for 
those two fabrics. One size set of replications was 16 square 
inches of cloth per square, and the other, 4 square inches per 
square.  On our grill, which was lined with aluminum foil, I 
would put down one piece of cloth at a time, fold it over, and 
light a match to it.  The second I touched the match to it, I 
started my stopwatch.  When the cloth caught on fire, I pressed 
the "Laps" button.  When either the cloth had smoldered, in 
which case I would just give the cloth some more seconds on its 
time before stopping the watch, or it had been consumed, I would 
press the "Stop" button.  I would read the first time that I 
recorded, the exposure-before-igniting-time, the burning time, 
and the whole time in seconds and record it on to my data chart.
 
III.  Analysis of Data:

The data I collected from my 4 in. square cloth pieces  
indicated that Nylon was the fastest to burn, (although Nylon 
was never fully consumed), and Linen the slowest. The average 
time Nylon took to burn was 38.79 seconds, Satin Taffeta was 
41.24 seconds, Terry Cloth was 78.28, Brushed T-Shirt Cotton was 
86.43 seconds, Broad Cloth was 46.39, Linen was 133.74 seconds, 
and Rayon was 66.87. These are the times for the 4 in. square 
pieces of cloth.  As for my hypothesis, it was generally proven 
wrong by the fact that only 3 groups of cloth burned in under 
one minute on average.  One of the groups burned on average in 
over two minutes.

The data I collected from my 16 in. square cloth pieces 
indicated that Satin Taffeta, this time, took the shortest time 
to burn; and Linen, again, the longest time to burn.  Nylon 
averaged to burn in 35.22 seconds, Satin Taffeta in 33.53 
seconds, Terry Cloth in 55.81, Brushed T-Shirt Cotton in 103.36 
seconds, Broad Cloth in 48.79, Linen in 121.05 seconds, and 
Rayon in 76.47.  As my hypothesis is concerned, it was, again, 
generally proven wrong because only 4 groups of cloth burned in 
under one minute on average.  The Nylon and the Terry Cloth were 
never fully consumed during the project, so that may have caused 
numbers to be off and more groups in the 4 in. square group to 
have less types of cloth burn in under one minute.

IV.  Summary and Conclusion:

I have found out that most fabrics burn moderately fast, but 
nothing close to the ones that you might hear about in colonial 
stories with women who stand too close to the fire and their 
dresses go up in flames in a snap.  Most of the cloth burned 
slowly.  Therefore, I reject my hypothesis because I thought 
that most of the fabric would burn quickly, but they burned 
moderately fast.

V.  Application:

These findings could improve in-home fire safety for many 
families by encouraging them to buy, and more stores to use, 
linen in their clothing, although it is kind of a weird fabric 
for regular clothing.  But it could be encouraged to be more 
widely used in household fabrics in general for human safety.  
It could prevent even the smallest things like table top candle 
accidents from spreading all around the house.  These are some 
ways that my findings can make the world a better place.


Title:  Which Household Items Lubricate Metal The Best?

Student Researcher:  Mandy Mitchell
School Address:  Hillside Middle School
                 1941 Alamo
                 Kalamazoo, Michigan  49007
Grade:  7
Teacher:  Barbara A. Minar

I.  Statement of Purpose and Hypothesis 

In my experiment, I planned to find out which household items 
lubricated metal the best.  Of baby oil, Softsoap, vegetable 
oil, and Vaseline, I thought vegetable oil would lubricate metal 
the best followed by baby oil, Softsoap, and Vaseline.

II.  Methodology 

To test my hypothesis, I built a ramp 57.5 cm tall, 13 cm wide, 
and 103.5 cm long. This created a 29.5 degree angle from the 
surface it sits on and the slanted board. The slanted board was 
covered with a very smooth aluminum sheet 1 mm thick.  I also 
bought a steel block l cm wide, l cm tall, and 14 cm long.  Then 
I rounded the edges on the corners to make sure there weren't 
any burrs.  I also gathered distilled white vinegar, Vaseline, 
baby oil, vegetable oil, paper towels, a level surface big 
enough to set the ramp on, a stopwatch that is accurate to the 
hundredth of a second, a 5 ml calibrated container, four 
disposable paint brushes, and a permanent marker.  

In doing the experiment, the controls were the degree of the 
ramp, the surface of the ramp, the positioning of the block, the 
amount of the lubricant, the method of timing the block, the 
method of cleaning the ramp, the spread of the lubricant, the 
type and brand of the paint brushes, and the brands of the 
lubricants, vinegar, and paper towels.  

To begin, place the ramp on the level surface.  Measure out 5 ml 
of whatever lubricant you decide to start with.  To keep from 
confusing them, label the paint brushes with the permanent 
marker.  Also color one end on one side of the metal block with 
the permanent marks.  When testing, this part of the block 
should face upward and be nearest the top of the ramp.  To test, 
brush the 5 ml of lubricant as evenly as possible onto the metal 
surface of the ramp.   Ready the stopwatch and release the metal 
block from the top edge on "3, 2, 1, GO!" (releasing on "GO!").  
Stop the watch when the front edge of the block touches the end 
of the ramp.  Record the time on your data chart.  Now use the 
paper towels and white vinegar to remove the lubricant from the 
ramp.  Do not touch the surface again because of the oil from 
your fingers.  Repeat the experiment for each of the four 
lubricants three times.

III.  Analysis of Data: 

When I finished the experiment I found my hypothesis to be 
almost completely unsupported.  Instead of vegetable oil having 
the best (shortest) time, followed by baby oil, Softsoap, and 
lastly Vaseline; Softsoap came in first followed by baby oil, 
vegetable oil, and Vaseline.  The only part that turned out as I 
had predicted was that Vaseline would come in last.  These are 
the average times it took the block to read the end of the ramp 
with each lubricant:

            Softsoap      = 0.63 sec. 
            baby oil      = 0.88 sec.
            vegetable oil = 1.01 sec.
            Vaseline      = 1.22 sec.

IV.  Summary and Conclusion: 

In my experiment, I found that, after three trials, Softsoap had 
the best average, baby oil came in second, vegetable oil was 
third, and Vaseline was last.  Therefore, my hypothesis was 
unsupported.  My hypothesis stated that vegetable oil world work 
the best and that it would be followed by baby oil, then 
Softsoap, and finally Vaseline.  

One thing I learned from this experiment was that just because a 
substance is dense does not mean it cannot lubricate.  This and 
the data I collected caused me to reject my hypothesis.  I ran 
into only one problem while doing the experiment.  That problem 
was the cleaning of the ramp.  I found using Dawn dish snap to 
be unfair because one of the lubricants was soap, also.  It also 
left a very thin residue.  In its place, I used plain distilled 
white vinegar.  This solved my problem.

V.  Application: 

To generalize my findings, I would say I have found that a 
substance's ability to lubricate is not determined by its 
density.  There are not any uses for this knowledge now, but in 
the future we may use these products in cars or moving 
sidewalks.  The possibilities are endless.  Even after this 
experiment, there are still questions unanswered.  "Does the 
angle of the ramp affect the ratio of the differences of the 
lubricant's times?" is only one. "Would it make a difference if 
the ramp was longer?" is another.  Despite this research there 
are many questions yet unanswered.


Title:  Root Development

Student Researcher:  Stephanie Frey
School Address:  Hillside Middle School
                 1941 Alamo
                 Kalamazoo, Michigan 49007
Grade:  7 
Teacher:  Barbara A. Minar

I.  Statement of Purpose and Hypothesis 

I wanted to find out which type of water would help plants grow 
roots the best, salt water, sugar water, distilled water, or 
well water.  I thought that well water would help plants grow 
the longest roots and distilled water would grow the second 
longest roots. I thought the plant given sugar water would have 
the third longest roots and the plant given salt water would 
grow the smallest roots.

II.  Methodology: 

I tested my hypothesis by purchasing a pothos at Wedel's 
Greenhouse and asked the sales people which plant would make the 
best clippings.  I cut off four leaves and kept their stems.  I 
placed one plant clipping in each glass.  I filled each glass 
with 150.0 ml of one of the different types of water.  I then 
put plastic wrap over the mouth of the glass to cover the 
opening to prevent evaporation.  I cut a hole in the plastic 
wrap and put the stem of the plant into the water.  I put all 
the glasses on the same window shelf in the southern part of our 
dining room for 52 days and watched the root growth and changes 
in the plant clippings.  I did not take plants out of the water 
until day 49 for actual measurements.  If I had taken them out 
of the water to measure them, the roots may have been damaged 
and would affect the growth and the results would have been 
inaccurate.  My independent variable is the water type.  The 
dependent variable is the root development.

III.  Analysis of Data: 

My data showed sugar water grew roots 2.25 cm long. Distilled 
water grew roots 0.50 cm long. Well water grew roots 0.50 cm 
long. Salt water grew roots 0.0cm long.

IV.  Summary and Conclusion:
 
When I experimented to see if plant clippings grew longer roots 
with sugar water, salt water, distilled water, or well water I 
found the best root growth in the sugar water.  Salt water grew 
the least roots.  I had thought distilled water would have grown 
the longest roots.  This part of my hypothesis was not supported 
by my data.  I also thought that salt water would not grow long 
roots. This part of my hypothesis was supported by my data.

V.  Application: 

From my research, I learned that distilled water can grow roots 
even though the minerals have been removed, because of the 
organic materials that are left behind.  The amount of organic 
materials depend upon the source of the water. City water can 
have more chemicals in the water like fluoride for our teeth.  I 
found this out when I called the 800 number from Country Fresh, 
the company that sold me the distilled water.  Water out in the 
country can have more organic materials in it because of the 
crops and livestock.  Farmers use more fertilizers and this can 
get into the well water.  Further research with salt water 
plants world be helpful.  Poorer nations could use this 
information with crops when their rain fall is low and the 
mineral content is high.  This information would be helpful to 
farmers trying to propagate plants.


Title:  The Decomposition Of Different Foods In Different
        Environments

Student Researcher:  Michael DeSantis
School:  Edgemont Jr./Sr. High School
         200 White Oak Lane
         Scarsdale, NY 10583
Grade:  7
Teacher:  Mr. Rubenstein

I.  Statement of Purpose and Hypothesis: 

I wanted to find out which of the foods that I gathered would 
decompose faster in two different environments.  My first 
hypothesis stated that soil will help the food matter decompose 
faster rather than the twigs + grass mixture.  My second 
hypothesis stated that the food matter will decompose faster for 
the room-temperature group rather than the cold-temperature 
group.  My third hypothesis stated that, of the three foods that 
I selected (oranges, tomatoes, and potatoes), the tomatoes will 
decompose the fastest. 

II.  Methodology:

For my experiment, I used plastic cups, soil, twigs, grass, a 
shoe box, labels, a refrigerator, tape, a marker, a tomato, a 
potato, and an orange. 

After gathering the materials that I needed, I constructed the 
base or containment for each of the two groups (cold/room 
temperature).  I then put the plastic cups into the bottom of 
the shoe box (6 cups) and taped them down.  I then filled them 
with either the soil or the twigs + grass.  I repeated this for 
the top side of the shoe box.  I placed the food into the 
selected cups.  Before I started to fill the cups, I made a data 
chart.  I placed one box into the refrigerator and one box in my 
living room.  I took a picture of each box every week and 
recorded the percent of the food not decomposed of each cup 
every day for 24 days.  

The controlled variables were the size of the cups and the 
amount of soil and the amount of twigs + grass mixture used.  
The manipulated variable was the temperature in which each box 
was kept.  The responding variable was the rate of decomposition 
of the foods being tested. 

III.  Analysis of Data: 

As it turned out, my hypothesis was not entirely correct. The 
food in the room-temperature box did in fact decompose faster.  
The tomatoes also decomposed faster in both boxes.  But the food 
in the cups containing twigs + grass decomposed faster than the 
food in the cups filled with soil.

                          Room Temperature 
                          % Not Decomposed
                     Soil                   Twigs and Grass
Date      Tomato%  Orange%  Potato%   Tomato%  Orange%  Potato% 
4/29/98     84       98       99         79      96       100
5/ 2/98     52       90       96         48      87        99
5/ 6/98     42       80       95         39      78        97
5/ 9/98     42       73       95         39      72        96
5/13/98     40       72       94         39      71        96
5/16/98     40       71       94         39      69        95
5/19/98     40       70       94         38      68        94

                          Cold Temperature 
                          % Not Decomposed
                     Soil                   Twigs and Grass
Date      Tomato%  Orange%  Potato%   Tomato%  Orange%  Potato% 
4/29/98     97       98       99         79      98       100
5/ 2/98     94       94       97         94      97        99
5/ 6/98     86       89       96         89      91        98
5/ 9/98     82       88       96         85      89        97
5/13/98     81       88       96         80      88        97
5/16/98     78       88       96         75      87        97
5/19/98     77       88       96         74      87        97

IV.  Summary and Conclusion: 

I found out that tomatoes are one of the fastest decomposing 
foods, especially being compared with oranges and potatoes.  But 
to my surprise, I also found out that twigs + grass do 
contribute by increasing the rate of decomposition compared to 
soil.  Room temperature is also better than cold temperature for 
decomposing matters which is what I expected before conducting 
this experiment. 

V.  Application: 

The information I found out while conducting my experiment can 
help the earth.  For example, now that I know that twigs + grass 
are better for decomposing foods than soil, people should use 
twigs and grass for the ground (especially for a compost pile).  
Also, land fills or places trying to minimize the amount of 
garbage (including food scraps) should use twigs and grass for 
the ground. Also, knowing that tomatoes are very fast at 
decomposing, is useful information when planning a compost pile.
 

Title:  The Effect Of pH On The Life Span Of A Tadpole

Student Researcher:  Aaron Friedman
School:  Edgemont Jr./Sr. High School
         White oak Lane
         Scarsdale, New York 10583
Grade:  7
Teacher:  Ms. Maria Russo

I.  Statement of Purpose and Hypothesis: 

I wanted to know more about the effect of pH on a tadpole's life 
span.  pH is how acidic or basic a liquid is.  Does the pH of 
water in which a tadpole is placed affect its life span?  Will 
neutral water tadpoles live longer then acidic or basic ones?  
My hypothesis stated that, if one tadpole lives in neutral water 
and another lives in acidic water, the one in neutral will live 
longer.  I feel that a tadpole's water is naturally neutral and 
if it is anything else it may be in danger of death or injury.

II.  Methodology: 

In order to test this hypothesis, I needed 6 bowls, 6 tadpoles, 
tadpole food, acidic drops, basic drops, indicator strips, 
water, and a net. 

First, I filled 6 bowls with water.  Two bowls then received 15 
drops of acidic drops making their pH 9.  Two other bowls were 
left at pH 7.  The last two bowls received 15 drops of basic 
drops making their pH 5.  I made sure each pH was correct by 
testing the water with indicator strips everyday.  I put one 
tadpole in each bowl.  Every other day, I changed the water and 
reapplied the drops.  Everyday, I feed them a pinch of food.  
There are many other variables that I controlled.  The tadpoles 
were all placed on the same table and received the same amount 
of oxygen.  They also received the same amount of food and 
water.  Their water was changed at the same time and they were 
fed at the same time.  

The manipulated variable is the pH.  The acidic tadpoles 
received 15 drops of acidic drops.  The basic tadpoles received 
15 drops of basic drops.  The responding variable is the number 
of days the tadpoles stayed alive.

III.  Analysis of Data: 

My hypothesis was pretty correct.  The acidic tadpoles did die 
on the first day.  As for the basic tadpoles, they did survive 
the whole test (33 days).  As the acidic tadpoles were dying, 
their skin was shedding and they were trying to jump out of the 
bowl.  Many other odd occurrences happened during my testing.  
For example, for about a week, one tadpole we lying upside down 
and gasping for breath.  Eventually, this ailment went away and 
the tadpole was fine.  

Tadpole #                      Days Alive    

Acidic Tadpole #1                 1
Acidic Tadpole #2                 1
Neutral Tadpole #1                33
Neutral Tadpole #2                33               
Basic Tadpole #1                  33
Basic Tadpole #2                  33

IV.  Summary and Conclusion: 

The acidic tadpoles did die before the neutral ones, but the 
basic ones stayed alive as long as the neutral ones. Therefore, 
tadpoles are able to survive if the pH is slightly basic.  But 
if the pH becomes slightly acidic, the results may be fatal.

V.  Application:

In this fast changing world, many environments are being 
destroyed and even ruined.  If a tadpole needs to live in water 
with a pH of 7, it is important to know that so we won't 
accidentally change the pH.  Also, things like acid rain could 
definitely harm the water's pH.  Not only is the pH of water a 
problem for tadpoles, but all marine animals may be facing this 
potential problem.  I hope to continue my studies and may expand 
it to include other animals.
 

Title:  Mouthwash And Bacteria

Student Researcher:  Chloe Asselin
School:  Edgemont Junior/Senior High School
         White Oak Lane
         Scarsdale, New York 10583
Grade:  7
Teacher:  Maria Russo

I.  Statement of Purpose and Hypothesis:

I wanted to know more about how clean your teeth could be by 
using mouthwash.  To find how efficient the mouthwash was, I 
found out how much bacteria was left after using two different 
brands of mouthwash.  I wanted to know if Fresh Burst Listerine 
worked better than Tom's of Maine Natural Mouthwash.  My 
hypothesis stated that Fresh Burst Listerine worked better than 
Tom's of Maine Natural Mouthwash.

II.  Methodology:

First, I wrote my hypothesis thinking that Fresh Burst Listerine 
was better than Tom's of Maine Natural Mouthwash because Tom's 
of Maine did not say, on the bottle, that it destroyed bacteria.  
I then got 23 grams of powdered agar, 1,000 ml of cold distilled 
water, petri dishes, masking tape, and Q-tips.  I already had 
the bottle of Fresh Burst Listerine and the bottle of Tom's of 
Maine Natural Mouthwash. 

The manipulated variable was the kind of mouthwash.  The 
responding variable was how much bacteria grew.  The variables 
held constant were the size of the petri dishes, the amount of 
medium in each petri dish, the amount of mouthwash used, and the 
amount of bacteria spread in each petri dish.

For conducting the experiment, I first had to make the agar gel.  
I suspended 23 grams of the medium into 1,000 ml. of cold 
distilled water.  I then heated the medium to boiling to 
dissolve it completely.  To sterilize the medium, I put it in 
the microwave and heated it minute by minute.  When the medium 
began to bubble I turned off the microwave.  I then poured the 
medium into the deeper dish of the petri dish.  Next, I taped 
the petri dish and inverted it.  The petri dishes were kept in a 
warm place.

Then the real experiment was done.  I took the tape off the 
petri dish and took the top off.  At 7:30 AM and 9:30 PM, my 
brother and I used different mouthwash.  We moved it back and 
forth in our mouths 50 times.  We then spit it out and wiped a 
Q-tip along our bottom teeth.  Next the Q-tip was smeared, in 
three different places, on the agar gel in the petri dish.  For 
2 days, my brother and I did these tests at 7:30 AM and 9:30 PM.  
I also did a control for each day, swabbing a Q-tip without a 
rinse with mouthwash.  

Next, I recorded my rating of the amount of bacteria grown on a 
scale of 0-4.  Finally, I accepted or rejected my hypothesis and 
wrote a summary and conclusion. T he scale is from 0-4. O being 
no bacteria, 1 being a little bacteria, 2 being some bacteria 
and so on.

III.  Analysis of data:

For 2 days, my brother and I did tests regarding bacteria. I 
observed that Fresh Burst Listerine worked better than Tom's of 
Maine Natural Mouthwash.  The average number for Fresh Burst 
Listerine was 3 (a lot of bacteria).  The average number for 
Tom's of Maine Natural Mouthwash was 4 (plate was overgrowing!!).  
The control stayed the same both days with an average of 3 (a 
lot of bacteria).

IV.  Summary and Conclusion:

Fresh Burst Listerine worked better than Tom's of Maine Natural 
Mouthwash.  The control had a lot of bacteria, but not 
overflowing in the petri dish.  On the bottle of Fresh Burst 
Listerine, it says the mouthwash will kill germs and keep your 
breath fresh.  On the Tom's of Maine bottle it just says the 
mouthwash will keep your breath fresh.  Therefore, I accepted 
my hypothesis which stated Fresh Burst Listerine would work 
better than Tom's of Maine Natural Mouthwash.

V.  Application:

I can apply this information to my life because I now know to 
use Fresh Burst Listerine if I want clean teeth and a fresh 
breath, which indicates the removal of bacteria.  The Consumer 
Report Magazine should also conduct this experiment to show the 
public the benefits of using Fresh Burst Listerine.