This year for our
science fair project we decided to work with bioluminescent bacteria. We
heard of bioluminescent bacteria through our science teacher. From there
we decided to investigate. Bioluminescence is the giving off of light by
an organism without heat. We read that bioluminescent bacteria are being
used to diagnose the amount of pollution in water.
We believe that the pollutants will decrease the
amount of light bioluminescent bacteria produce because through our
investigations we have discovered that they produce less light when
introduced to pollutants. We used:
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Bioluminescent bacteria
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Metal transferring loop
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Hudson River water
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Tap water
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Hair gel
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3 in 1 oil
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Bunsen burner
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Sparker
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Rubbing alcohol
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Napkin
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Pen/pencil
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Paper
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Test tubes
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Goggles
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dropper
To
transfer the bacteria:
First, we clean the area where we were to work in with rubbing alcohol.
We turn on the Bunsen burner with a sparker. We sterilize the metal
transferring loop with which we are to transfer the bacteria from the
dish to the tube. After the loop glows bright red, meaning it is
sterilized, we cool it down on agar, nutrient food for bacteria, where
there is no bacteria. Afterwards, we scrape off enough bacteria from the
dish with the loop and move it over to the test tube. Before placing the
bacteria in the tube, we have to sterilize the opening of the tube by
placing it over fire for a couple of seconds. After we transfer the
bacteria, we place them in the dark. We have to transfer the bacteria
every 2 days or else it will die.
To
insert pollutants:
We go into a dark room to check if the bacteria are glowing. If it is,
we observe how many sheets of blank paper it takes to block out the
light produced by the bacteria. Next, we insert the pollutant and
examine if the pollutant has decreased the amount of light the bacteria
gave off by seeing how many blank sheets of paper it takes to block out
the light.
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Pollutant
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What Happened
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Tube # 1
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Hair
Gel
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Before,
it took 4 sheets of paper to block out the light. After it met the
hair gel, it took 1 sheet of paper to block the light out.
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Tube
#2
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3
in 1 oil
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Before,
it took 3 sheets of paper to block out the light. After it met the
oil, it still took 3 sheets of paper to block out the light.
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Tube
#3
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Tap
water
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Before,
it took 5 sheets of paper to block out the light. Afterwards, when
contacted with tap water, it took 4 sheets of paper to block out the
light.
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Tube
#4
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Hudson
River water
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Before,
it took 5 sheets of paper to block out the light and afterwards it
took 4 sheets.
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We tested how many sheets of paper it takes to block
out the light of the bioluminescent bacteria before and after the drop of
pollutants were placed in the tube.
In test tube number one, before the pollutant was
arranged in to the tube, it took 4 sheets of blank paper to block out the
light. After the bacteria in test tube #1 met the hair gel, it took only
one sheet of paper to block out the light. This means that the light
decreased by 75%.
In test tube number 2, it took 3 sheets of paper to
block out the light before the drops were placed in the tube. After the
bacteria met the 3 in 1 oil, the number of sheets of paper it took to
block out the light stayed the same; meaning that the bacteria’s
encounter with the oil did not increase or decrease it light production.
In test tube #3, it took 5 sheets of paper to block
out the light the bacteria produced. However, after a drop of tap water
was placed in the tube, it took 4 sheets of paper to cover up the light.
The percent of decrease was 20%.
Test tube #4’s percent of decrease was much similar
to the percent of decrease of test tube #3. This is so because it took 5
sheets of paper to block out the light the bacteria made. Afterwards, when
one drop of Hudson River water was placed in to the tube, it took 4 sheets
of paper to cover up the light. The percent of decrease was also 20%.
Discussion:
Our
hypothesis was proven correct and at the same time proven wrong. We
thought that the pollutants were to decrease the amount of light produced
by bacteria because we knew that pollutants have affected the ocean in
which these bacteria live in. We also know that these pollutants have
harmed other marine organisms. In the test tubes, there was a
bioluminescent bacterium whose light was decreased because of the four
pollutants we used. However in one of the tubes, the light did not
decrease or increase. The results prove so. We used four test tubes in
which bacterium was living in with its nutrient food, agar. The four
pollutants used were 3 in 1 oil, Hudson River water, tap water, and hair
gel. The Hudson River water, tap water, and hair gel decreased the amount
of light the bacteria produced; nevertheless, the 3 in 1 oil did not. We
think this is so because bacterium is used to the ocean’s conditions of
being polluted. The Hudson River water and the tap water probably did
affect it because the bacterium’s environment is salty, and not
‘sweet’ as in the river and tap water. There are also many other forms
of bacteria in these waters so they probably could have been an element of
the decrease. If we were to make this project much better, we would use
pollutants or polluted liquids that harm humans such as poisons. We would
observe if these poisons would harm bacteria as well as humans. We could
also use hair products or different medicines. We could use oils from fish
and water from different places such as the sewer.
We wanted to work in a project where we could observe a life form,
in this case, bioluminescent bacteria. We wanted to work with chemicals or
liquids as well. To add a twist, we would see how many sheets of paper it
takes to block out the light from the bacteria before and after the drops
of chemicals were placed in the test tubes. So we decided to combine the
three ideas into one. We came up with the question of what would happen if
different liquids were placed together with bacteria.
We brainstormed for different liquids/chemicals and
we came up with hair gel, tap water, water from the Hudson River, and 3 in
1 oil, which is used in everyday purposes in the homes, mainly for fixing
creaky doors. We got the bacteria that we were to use, called vibrio
fischeri, and the special tools we were to need from a special science
supplier lab. The bacteria came in a petri dish and from this dish were to
transfer the bacteria into a test tube because if we did not, they would
die. After the transfers were completed, we tested out the liquids and
chemicals on the bacteria.
In the first test tube, it took 4 sheets of paper to block out the
light before and 1 after the bacteria met the hair gel. The percent of
decrease was 75%. In the second test tube, where the bacteria met the 3 in
1 oil, it took 3 sheets of paper before and after the drops were in the
tube, meaning the amount of light did not increase or decrease. In test
tube #3, it took 5 sheets of paper to block out the light before and 4
after when the drop of tap water was placed in the tube. The light
decreased by 20%. Finally, in test tube #4, it took 5 sheets of paper to
block out the light before and 4 after when 1 drop of Hudson River water.
The percent of decrease was 20%.
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