Researched by Lindsay B.  1998-99

PURPOSE  HYPOTHESIS   EXPERIMENT DESIGN  MATERIALS  PROCEDURES   RESULTS: "Weight to Sink"  RESULTS: "Floating Time"  CONCLUSION  RESEARCH REPORT  BIBLIOGRAPHY

The purpose of the two experiments was to determine if the buoyancy of four different fibers could be improved by treating them with a waterproofing spray.  I wanted to make the fibers hold more weight and float longer after being treated.

I became interested in this idea when I cut open a personal flotation device to find out what kapok looked like.  Before that, my project was just another original experiment.  When I saw what kapok was, I was really interested.  It didn’t really look like cotton, and it was very light and soft.  When I did a pre-experiment on the kapok, I found out that it was hard to sink.  I wondered if any other fiber could float as well as kapok.  I also wondered if I could improve kapok.  I also saw that the kapok had a plastic cover over it.  I wondered what would happen if the cover had a hole in it.  I wondered that if it was treated and had a hole in it, it would float better than it would with a hole and no treatment.  I wondered how well the other fibers would do under these situations, too.

The information gained from this experiment will benefit people who are in search of the right flotation device that can still hold a lot of weight when in a bad situation.  If I can improve fibers by waterproofing them, then they might be able to support more weight and allow a person to swim to shore before sinking.

My hypothesis is that kapok, cotton, polyester, and llama wool can all hold more weight and have a longer floating time by treating them before use.  Based on my pre-testing, I know that cotton and polyester won’t hold much weight before becoming submerged.

I base my hypothesis on my own experimenting.  Before I did my real experiment, I tested how well kapok floated compared to cotton and polyester.  At that point, I hadn’t yet decided to use llama wool.  I put about ten grams of kapok, cotton, and polyester in separate ziploc bags.  Then, I put a one hundred-gram weight in each bag, closed it, and placed each in a tub of water.  Almost immediately, the cotton and polyester sank.  I had to use almost eight of those weights to sink the kapok.  When I was done, I started cleaning up.  I picked up the kapok and felt that it was dry, almost like it had a natural waterproofing to it.  If I treat it even more with my own waterproofing treatment, then the kapok could be made more buoyant.

The constants in this study for both experiments were:

• The same mass of fiber was used for each sample. (5g)
• Approximately the same amount of spray was used on each sample waterproofed.
• The same type and size ziploc bag was used for each test. (Ziploc Snack Size)
• Similar weights (100g masses and pennies) were used in each test.
• For the tests that included fibers that were presoaked, the same soaking time was used. (15 minutes)
• The average mass required to submerge a certain type of fiber in the first test was used as a downward force for the fibers tested in the second test.

In the first experiment, I tested all four types of fibers dry and untreated as a control for each fiber.  I tested three different manipulated variables for four types of fibers.  The first manipulated variable was testing the four types of fibers dry and waterproofed.  The second was testing them presoaked and waterproofed.  The final variable was testing the four types of fibers untreated and presoaked.

The responding variable for the first experiment was the number of one hundred-gram masses and pennies added to the bags of fibers to get them to submerge.

To measure the responding variable, I measured the amount of mass required to submerge the fibers.  I used the one hundred-gram masses and pennies.

In the second experiment, I also tested all four types of fibers dry and untreated as a control.  The manipulated variables for this experiment are the same as the "Weight to Sink" experiment.  I tested three different manipulated variables for four types of fibers.  The first manipulated variable was testing the four types of fibers dry and waterproofed.  Next was testing them presoaked and waterproofed.  The third variable was testing the four types of fibers untreated and presoaked.

The responding variable for the second experiment was the amount of time it took for the fibers to become submerged.

To measure the responding variable, I used a stopwatch to time the fibers until they sank.

Procedures for "Weight to Sink":

1) Measure five samples of kapok, letting each weigh five grams.

2) Using a pencil, poke five holes into five Ziploc Snack Size bags.  Poke one hole in each
    corner, and one in the middle.  If the hole makes more of a slice when poking it, get a new
    bag.

3) Put each sample into it’s own bag.  Do not seal the bag.

4) Place one, one hundred-gram mass into each of the bags of kapok.

5) Place one bag into a bucket of water.

6) One at a time, place pennies into the bag.

7) When the bag sinks, count the number of pennies inside the bag.

8)Weigh the pennies on the Triple Beam Balance.

9) Record your data, and be sure to count the starting one hundred-gram weight.

10) Test the other four samples of kapok, using the procedures above.

11) Repeat steps 1-3 for the cotton, polyester, and llama wool.

12) Instead of using a one hundred-gram mass for step four, start with five pennies.

13) Repeat steps 5-12 for the cotton, polyester, and llama wool.

14)Average out your data for each fiber tested.

Procedures for "Floating Time":

1) Measure five samples of kapok, letting each weigh five grams.

2) Using a pencil, poke five holes into five Ziploc Snack Size bags.  Poke one hole in each
    corner, and one in the middle.  If the hole makes more of a slice when poking it, get a new
    bag.

3) Put each sample into it’s own bag.  Do not seal the bag yet.

4) Place the average weight required to sink the fibers in the first experiment into the bag of
    kapok.

5) Seal the bag and squeeze the air out of it.

6) Place the bag into the bucket of water and start your stopwatch.

7) When the bag is totally submerged, stop your stopwatch.

8) Record the time it took to submerge on your data table.

9) Repeat steps 1-8 for the four other bags of kapok.

10) Repeat steps 1-9, using the cotton, polyester, and llama wool.

Procedures for Waterproofing:

1) Repeat steps 1-2 on the procedures above.

2) Thoroughly spray the fibers with the waterproofing spray.

3) Wait four hours, and then spray the fibers thoroughly again.

4) After twenty-four hours, test the fibers, using the procedures above.

5) If you are testing these fibers after being soaked, use the procedures below.  Then test the
    fibers, using the above procedures.
 

Procedures for Presoaking Fibers:

1) Repeat steps 1-3 on the first set of procedures.

2) Using the one hundred gram masses, submerge all the fibers needed of one type in a tub
    of water.

3) Leave them there for fifteen minutes.  Make sure all the air is tightly squeezed out of the
    bags.

4) Take the bags out of the water, squeezing the water out of the fibers.  Test the fibers,
    using the first set of procedures above.

When the weight of an object is more than the buoyant force, the object will sink.  If the buoyant force is equal to the weight of the object, the object can float at any level.  A fish can do this, too.  When the weight of an object is less than the buoyant force, the object rises.  It will rise to the surface and float there.

When an object is placed in water, some of the water is displaced.  The level of the water rises.  The weight of the water displaced is the same as the buoyant force.  A larger object that occupies more space displaces more water.  The strength of the buoyant force depends on the objects volume.

Archimedes’ Principle is applied to every fluid.  One cubic meter of air at sea level weighs about twelve Newtons.  A balloon that occupies one meter cubed has a buoyant force of twelve Newtons acting on it.

An object with a density over 1 g/cm3 will sink.  A steel bolt, or anything that’s steel will sink because it’s density weighs more than the water’s density.  The steel’s weight is more than the buoyant force of the water it displaces.  Between fluids of different densities, buoyancy can be observed.  The buoyancy of cooking oil is less than the buoyancy of water.  When oil and water are combined, oil floats to the top.

Type Two is the buoyant life jacket for when you’re near shore.  This type of vest usually looks like a horse collar and is worn like a bib.  It does have an unconscious turning ability, but it won’t turn as many people over onto their backs as Type One.

Type Three is the flotation aid.  These devices are most likely foam-filled, and they come in many different colors and styles.  These flotation aids aren’t designed to turn unconscious victims, but they provide protection for hypothermia.

Type Four devices are the kind that can be thrown to victims in the water.  They’re usually buoyant cushions, ring buoys, or horseshoe buoys.  They aren’t to be worn.  It is suggested that cushions should be checked often to see if they’re in serviceable condition.

Type Five flotation devices are for special use.  A Coast Guard approved Type Five device can be carried instead of any of the types one through four.  The Type Five device must be approved for the activity in which it’s being used.

Other personal flotation device requirements:

• The flotation device has to be the right size for the wearer.
• In emergencies, the flotation devices need to be readily accessible
• The US Coast Guard must approve the flotation devices and a label on the device must prove it.
• All flotation devices must be in serviceable condition.  The device has to be free of tears, rot, punctures, and water-logging, especially in kapok filled devices.

When the ripe fruit of the kapok is picked, the seeds and fibers are taken out and dried in the sun.  Then, many workers separate the seeds from the fibers, and pack the fibers into bails.

Kapok is verminproof and very light.  It doesn’t absorb water easily.  It’s used for filling mattresses and furniture.  It’s also used as a substitute for cork in life jackets.  In many of these uses, kapok is being replaced by synthetic fibers.  These fibers cost less, and are more durable.

When cotton is grown in the wild, it is perennial, but in cultivation, it has to be planted annually.  Cotton grows upright at a height of between one and two meters.  The probability for self-pollination is high.  After fertilization, the boll fibers begin to form.  On the surface of the seed, individual fibers grow from cells.  Three weeks after fertilization, the fibers are their full length.  They then become thin-walled hollow tubes filled with plant juices.  The plant now begins to deposit layers of cellulose.  The rate is a layer per day for three weeks, until mature.  When the boll bursts open, it contains up to fifty seeds with the lint fibers attached.  Short fuzz fibers, linters, are attached to the seed, too.  The average length of the lint fibers is 25.4 millimeters.   Linters have thicker walls and a larger diameter.  They’ll be about 2.5 to five millimeters.

Cotton grows in a hot environment.  It is confined to the region from forty-seven degrees north, to thirty degrees south latitude.  In the U.S., this area is from central California to southern South Carolina and south to the southern tip of Texas.  The major growing areas are Texas, California, southern Arizona, and the Mississippi River valley.  Growing cotton requires fertile, well-drained soil, with sufficient moisture.  It’s usually planted through March and May.

Of all plant fibers, cotton is the most widely used.  Cotton fibers are woven into soft, strong, absorbent fabrics, which are used to make clothing and other items.

For thousands of years, people have cultivated the cotton plant and woven it’s fibers into cloth.  Many people use cotton today, and many people have jobs in the cotton industry.

Leading cotton-growing countries are China and the United States.  India, Pakistan, and Uzbekistan also produce big cotton crops.  All together, these five countries produce about three-fourths of the world’s cotton.

Alkyds are common coating polymers, and when they’re fully polymerized, they’re cross-linked from one chain to another.   Most oil-based paints are made from the modified version of the hard, brittle properties of alkyds.  During World War II, unsaturated polyesters were developed and used in combination with fiberglass for boat hulls,  protective armor, and many other military uses.  Properties such as hardness, or resistance to fire, are produced by mixing unsaturated polyesters with plastics.  Dacron, Fortrel, and Kodel are produced by spinning polyethylene-terephthalate into synthetic fibers.  They are then stretched into films, which all have remarkable strength and resistance to heat, chemicals, mildew, and pest damage.  Electrical components, laminates, sails, and photographic film are made of these polyesters.  Glass and metals are often replaced by aromatic polycarbonate polyesters because they are less prone to shape distortion.  These polyesters are also used in photographic film for purposes like x-ray photography and aerial mapping.

The wool fiber is composed of keratin, a protein present in all hair, horn, and hoof cells.  Keratin has helical chains of amino acids, which are cross-linked to one another by disulfide bonds from the amino acid cystine.  The chains are coiled, and when they stretch as the wool is pulled, they recoil back into shape.

Wool fiber grows from a follicle in the dermal layer of the animal’s skin.  These follicles also produce a wax, or  grease.  This wool grease can be refined into lanolin, an important skin care product.  Lanolin is in many lotions.

Production of wool fiber is continuos, unlike the growing and shedding of hair of most other hair-growing animals.  The breed and diet of the animal determines the production of the wool fiber on the rate of growth.  Nutrition can and will affect the amount of wool grown in terms of length, diameter, and strength of the fibers.  Heredity also affects the type of coat.  For example, a lamb born with rough, coarse wool will probably not have wool woven into fleece.  Instead, it will be woven into yarn.  A lamb born with a more curly, smooth wool will probably be produced into fleece.

Almost half of the wool in world trade is grown in the Southern Hemisphere, particularly Australia.  Australia is by far the largest producer.  New Zealand, China, Argentina, Uruguay, South Africa, and the countries of Central Asia, are other large producers.

When the wool is sheared, it is separated into four different classifications.  To start with, the wool is judged as a certain type, and that indicates it’s suitability for a certain form of processing.  Next, The quality of the wool is determined.  Then, it’s grade is assessed.  This is an estimate of greatness affected by the fibers length, color, evenness, damage, and contamination.  Finally, the percent of clean wool available after the removal of grease and dirt is the fourth classification.

The original purpose of this experiment was to determine if the floating time of kapok, cotton, polyester, and llama wool fibers could be improved by treating them with a waterproofing spray.

The results of the experiment were that three of the four fibers were made more buoyant by waterproofing them.  The floating time of the kapok when treated and tested dry wasn’t good at all.  It’s average was only about five seconds.  However, the kapok that I treated and tested presoaked did the best out of all the tests on kapok, as you can see on my graphs.

The cotton didn’t improve when I tested it treated and dry.  It’s average floating time when treated and tested dry was much less than when it was tested without being treated, as you can see on my graphs.  When I tested the cotton presoaked and treated, however, it also did very well.  When I tested the cotton untreated and presoaked, it also did better than when it was treated and tested dry.

The polyester did improve by five seconds when I tested it dry and treated.  Again, though, it also improved when I treated it and presoaked it.  This was the test that it did the best in.  When I tested the polyester untreated and presoaked, it did better than the fibers that were treated and tested dry.

The llama wool was the only fiber that had a floating time that was the best test.  This, of course, was when I tested it dry and treated.  It improved by about one or two seconds.  For the first time in all four tests on the fibers, the treated and presoaked fibers turned out worse than any other test I did on the llama wool.

The original purpose of this experiment was to determine if kapok, cotton, polyester, and llama wool fibers could hold more weight before becoming submerged by treating them with a waterproofing spray.

The results of the experiment were that all of the fibers held more weight after
waterproofing them and testing them dry.  When I tested the kapok, it improved more by being treated with the waterproofing spray and tested after being presoaked.  The kapok was more buoyant when it wasn’t treated and when it was presoaked before being tested.

The cotton improved greatly.  It jumped from about 92 grams when tested dry and untreated, to about 123 grams when tested dry and treated.  These numbers are both averages for the cotton tests.

The polyester also held more weight after being treated.  The polyester was able to hold an average of around nine more grams.  This fiber held the least weight when I tested it presoaked and untreated.  The polyester did well when tested untreated and dry, but not as well as when I treated it dry and treated.

The llama wool’s buoyancy was also improved.  The average weight the llama wool could hold after being treated was about twenty grams more than when it was treated and tested dry.  The treated and presoaked fibers didn’t do as well as the other tests, and the untreated and presoaked llama wool held the least weight of the four tests on llama wool.

My hypothesis was that the kapok, cotton, polyester, and llama wool could be made more buoyant after being treated with a waterproofing spray.

The results indicate that my hypothesis should be accepted and rejected.  The kapok was the only fiber that didn’t hold more weight after treating it.  The buoyancy of the other three fibers, cotton, polyester, and llama wool, were all improved.  Three of the four fibers’ floating times weren’t improved when treated and tested dry.  However, two of the four fibers did improve when treated and presoaked before being tested.

Because of the results of this experiment, I wonder if kapok is not capable of being improved, and if that’s why manufacturers choose to use kapok.  Maybe kapok is even more buoyant when placed in water.  My results seem to indicate this as truthful.  I also wonder if I should have tested the fibers more than five times for each experiment.

If I were to conduct this project again, I would test the fibers in bags without holes.  This way, I could see what the buoyancy really is.  I would also be sure that I had my experiment design and procedures completely lain out before experimenting.  Otherwise, it can get confusing when you try to make sure you have all of the materials you need.  Another thing I would do would be to test other synthetic substances.  These substances would include Styrofoam and other foams and cushioning.

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Heimler, Charles H., et al, Focus on Physical Science, Columbus, Ohio, Merrill Publishing Company, 1987.

Fahselt, Diane, "Kapok," Groliers Encyclopedia, 1995

Finley, Thomas, "Polyester," Groliers Encyclopedia, 1995

Wilkinson, B.R., "Wool," Groliers Encyclopedia, 1995

Finley, Thomas, "Cotton," Groliers Encyclopedia, 1995

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