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Developers:
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Debra M. Liberman
Harding Middle School
Philadelphia, PA
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Dr. Terry M. Williams
John Cihiy
Rohm and Haas Company
Spring House, PA
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Grade
Levels:
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6 through 10 (with modifications); also could be used in
high school Science and Technology courses
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Goals:
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Ecology, Environmental Science, Microbiology, Applied
Technology
- To identify a simple paper making process.
- To identify materials used in paper making
process.
- To discuss some of the ecological implications of
recycling paper.
- To discuss some of the industrial implications of
recycling paper.
- To carry out step by step the procedure to find out
if microorganisms are present in different solutions as
used in industry today.
- To compare and contrast effects of biocides on a pulp
solution.
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Specific
Objectives:
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- To identify the presence of microorganisms using
various dyes
- To determine the effect of biocides on the reduction
of living things in stream water mixed with pulp.
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Teaching
Tips:
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- Make sure to allow for two consecutive school days to
elapse before examining pulp solutions.
- A blender could be used in place of egg beater.
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Background:
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True paper making dates back to the first century in
China. The basic process has remained essentially unchanged.
First, you must separate the cellulose fibers. Second, you
mix them with water. Third, you place them on a screen to
form a sheet and then you dry the sheet to form the paper.
Cellulose is a fibrous substance which is found in the
cell walls of plants. These fibers are not destroyed in
paper making. When we recycle paper, we rejoin these
hair-like fibers.
In industry, paper is made similarly but with high
powered machinery. Again, in paper making, water is
necessary. All living things need water. A body of water
will attract microorganisms. In the making of paper, the
pulp allows many nutrients to become available as food for
microorganisms. As a result, microorganisms form and can
affect the process of paper making in industry.
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For
Further
Study:
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- Compare the composition of man-made paper with that
made by paper wasps.
- Have students do research projects on various types
of microorganisms.
- Take samplings of water from a stream at locations
varying in:
a. amount of sunlight
b. rate of flow of water
c. depth
Then test for microorganisms with resazurin, TTC and
phenol red.
- Determine the lowest concentration of bleach which
will kill microorganisms (or just design the procedure to
do so.).
- Find biocides in the home in various products using
the labels.
Examples: BHT, BHA, benzoates, sodium benzoate.
- Do a science project comparing various biocides and
their strength.
- Interview a microbiologist on the uses and problems
with biocides.
- Find advertisements in trade journals that have to do
with biocides.
- Observe the effects of biocides on different types of
plants.
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Vocabulary:
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resazurin
machine
technology
phenol red
triphenoltretruzolium chloride
pulp
microorganism
incubate
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biocide
cellulose
conservation
fiber
pollution
solution
recycling
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Skills:
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Measuring
Manipulation of materials
Recording data
Interpreting data
Predicting and inferring
Making and testing a hypothesis
Applying and generalizing
Graphing
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Key Questions:
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How can you keep a pulp solution used in the recyling of
paper as free ofmicroorganisms as possible?
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Materials:
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Part I
toilet paper
hand lens
corn starch
rolling pin
felt- 2 pieces (20 cm square)
egg beater
screens 2 (15 cm square)
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Part II
stream water
tap water
sugar cubes
phenol red
15 jars (w. lids)
permanent marker
writing paper
droppers - 3
resazurin
tissue paper
newspaper
triphenoltretruzolium chloride (TTC)
paper towel
biocide solution (Chlorox�)
labels
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Part II:
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Title: How paper is made
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Purpose:
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- To demonstrate the presence of microorganisms in a
pulp solution.
- To demonstrate that a biocide kills these
organisms.
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Hypothesis:
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To be formulated by the students with help from the
teacher.
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Procedure:
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- 1. Put 360 ml of tap water in bowl A.
- Add torn soaked paper.
- Put 360 ml of stream water in bowl B.
- Add torn soaked paper in bowl B.
- Using an egg beater, slowly beat paper until you get
a creamy consistency.
- Add water, if necessary.
- Using 15 jars, label as follows:
a. tap water and resazurin
b. tap water and phenol red
c. tap water and TTC
d. tap water, sugar and resazurin
e. tap water, sugar and phenol red
f. tap water, sugar and TTC
g. stream water and resazurin
h. stream water and phenol red
i. stream water and TTC
j. stream water, sugar and resazurin
k. stream water, sugar and phenol red
l. stream water, sugar and TTC
m. stream water, sugar, biocide and resazurin
n. stream water, sugar, biocide and phenol red
o. stream water, sugar, biocide and TTC
- 50% head space is required in each jar so you want to
fill each jar so that half the space in the jar is air.
Each container must have a lid.
- Add 30 ml of required pulp slurry to each jar.
(stream vs. tap water slurry made in bowl A and bowl
B)
- Add a sugar cube to pulp slurry which requires
sugar.11. Add 8 drops of biocide (bleach solution) to
pulp slurry that requires it.
- Add 8 drops of resazurin to pulp slurry that requires
it.
- Add 8 drops of phenol red to pulp slurry that
requires it
- Add 8 drops of TTC to pulp slurry that requires
it.
- Note any color changes. Use Table 1 - initial.
- Note color changes Day 1. Use Table 1 - day 1.
- Note color changes Day 2. Use Table 1 - day 2.
- Note color changes Day 5. Use Table 1 -day 5.
- Please determine whether your slurry is acidic or
basic and place on chart the words acidic or basic.
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Teachers
Footnotes:
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Phenol red is a pH indicator which determines whether the
solution is an acid or base. Phenol red will turn yellow at
pH of 6.8 and red at a pH of 8.2. The teacher should explain
pH and acidity/basicity.
Resazurin is a dye used to indicate oxidation and
reduction in living things. It starts as a color and will go
to clear if oxidation reduction takes place. Note the color
it starts out on chart.
TTC is a dye which shows metabolism of living things.
Again it is a reduction reaction. It starts out clear in
solution and if there is activity, turns red. Note color at
start to finish.
NOTE: Pulp slurry in the presence of oxygen and glucose
will combine to produce acid and water and anaerobic
condition. If, in the presence of an effective biocide,
there is "no" reaction
Glucose + oxygen and pulp slurry combine to produce acid
and water and anaerobic condition.
Glucose and oxygen and pulp slurry and bleach combine to
produce no reaction. The stock solutions of indicator or dye
contain:
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Stock Solution
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PPM
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TTC
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3750
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Resazurin
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375
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Phenol Red
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1875
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Which jars contained microorganisms? How do you know? How
many?
Discuss results using paragraph form. Include answering
the key question, how do you keep microorganisms out of pulp
solution or recycled paper?
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Questions
for Part B:
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- List the three dyes used in identification of
microorganisms in this lab.
- Before you began this activity, what did you think
would happen and why?
- Use the Table 1 for day 1, 2, 3 and 5 to answer the
questions below:
a. In which pulp slurry did the pH change? Which dye
indicated the pH change?
b. In which pulp slurry could you say that microorganisms
existed? When would you see a color change if
microorganisms were present?
c. Was there a relationship between microorganisms
present and the pH?
d. What purpose was the use of the biocide in the stream
sugar slurry?
e. If you had to compare paper manufacturing to this
experiment, what substance in paper making compares to
the sugar?
- Look at Table 2. Make a Bar graph using information
from Table 1, day 1, 2, 3 and 5.
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Extension:
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Follow the same procedure in doing Part II but use
rubbing alcohol as the biocide.
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Essay for
thought:
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With the gray matter in your head, explain your reactions
to the following:
- Can microorganisms survive in a foreign atmosphere
such as Mars, Jupiter or Saturn? Why or why not? What
factors would you have to consider?
- Would biocides be useful in a foreign atmosphere?
Consider things like
- temperature, carbon dioxide, oxygen, gravitational
forces.
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References:
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Microbiological Laboratory Techniques by Arnold I.
Miller, D.C. Heath & Co., 1976.
Franklin Institute - Museum to Go - "Basic Paper Making",
Museum to Go Resource Center, MCMLXXXVII
Basic Bacteriology: Its Biological and Chemical
Background, C. Lamanna, Williams & Wilkins, 1973.
Biological Science: An Ecological Approach, BSCS Green
Version, Third Edition, Rand McNally, 1977.
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TABLE 1
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Substance
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pH
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Resazurin
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Phenol Red
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TTC
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Tap Water
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Tap + Sugar
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Stream
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Stream + Sugar
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Stream, Sugar, Biocide
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TABLE 2
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How many
micro-organisms?
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High
Moderate
Low
Zero
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Tap Water
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Tap + Sugar
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Stream
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Stream + Sugar
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Stream, Sugar and Biocide
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