Transcript The Effect of Shampoo on the Tensile Strength of Hair

The Effect of Shampoo on the
Tensile Strength of Hair
Barbara McHugh
9th Grade
Academy of Notre Dame de Namur
Problem
What effect does shampoo have on the
tensile strength of hair?
Research
 Hair is mostly made up of the protein keratin. It
is also made up of natural oils, produced from the
sebaceous gland, and water.
 The sebaceous gland adds a layer of protection, and
keeps hair shiny and healthy.
 A hair strand has three different layers to it; the
cuticle, outside layer, the cortex, middle layer,
and the medulla, the soft core. The hair root from
which the hair grows is called the follicle, and
tiny blood vessels in the follicle nourish the hair
root to keep it growing. Once the hair grows and
reaches the skin’s surface, the cells that compose
the strand die.
Research
 Hair is composed of amino acid chains which are
found in the cortex of the hair. These amino acids
contain carbon, hydrogen, oxygen, nitrogen, and
sulfur, and are held together by peptide bonds
which can turn into polypeptide chains.
 These polypeptide chains have side bonds. There
are salt bonds, hydrogen bonds, and disulfide
bonds. Salt and hydrogen bonds are more common,
but heat and moisture break them. Disulfide bonds
are less common, but are stronger.
 Each side bond makes up one-third of each hair’s
strength.
Common Shampoo Ingredients
 Shampoo is about 80% water.
 Cocamide or cocamidopropyl give the bubbles and
suds to shampoo.
 Ingredients such as sodium citrate or citric acid
control the pH level of shampoo. They help to keep
hair smooth.
 Dimethicone and other silicones give hair a
coating and add smoothness.
 Polyquaternium keeps hair under control and easy
to handle.
 Ingredients like panthenol add moisture and give
hydration.
Hypothesis
If someone uses a shampoo that
contains certain ingredients, then it
may make their hair stronger or
weaker.
Materials
1 cotton towel
5 hair weaves
20mL of 3 different brands of
shampoos
A force meter and weights
7 400mL of 38.89°C water
2 plastic containers
Procedure
1.
2.
3.
4.
5.
6.
7.
8.
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10.
11.
Four plastic containers were set out.
Gloves were used when handling the weaves.
A container was filled with 400 mL of 38.89°C.
A weave was washed for 2 minutes with 20 mL of shampoo.
After washing for 2 minutes, the weave soaked for 2 minutes
on the side of the container of water.
The weave was then put in a new container of 400 mL of water
at 38.89°C and rinsed clean for 2 minutes.
Then the weave was laid flat down on a white cotton towel to
air dry for 24 hours.
This same procedure was repeated for 2 other weaves.
For a fourth weave, it was just washed in water for 2 minutes
in 400 mL of 38.89°C and then put on the towel to dry for 24
hours.
For the fifth weave, nothing was done to it; it was just
placed on the towel with the other four weaves for 24 hours.
After 24 hours, the five weaves were tested using the force
meter and weights in order to determine how much strength it
takes to break a strand of a weave.
Procedure
 3 Tests were done for each weave.
 The independent variable was the shampoo.
 The dependent variable was the tensile strength of
the hair.
 The control was the hair that was just washed in
water and the hair with nothing done to it.
 The constants included the same amount of pull on
the hair, same environment where the hair was
stored, and the same amount of water and shampoo
to wash the hair. The same type of hair was also
used for each test.
Weaves
 After 24 hours of drying, the weave with
Brand A shampoo was smooth, silky, and not
stringy or hard.
 The weave with Brand B shampoo was stringy,
hard, and not smooth.
 The weave with Brand C shampoo was crunchy,
stringy, and the hairs were stuck together
in groups.
 The weave with just water was smooth, and
similar to the weave with Brand A shampoo.
 The weave with nothing in it was also
smooth, but not as silky as the weave with
Brand A shampoo. The hair had static.
Brand A Weave
Brand B Weave
Brand C Weave
Weave w/ just water
Weave w/ Nothing
• These are the weaves after 24 hours of
drying
Tests
The room temperature for every day of
testing was the same at 21.11°C.
For every test, a strand of hair from
each weave was tied in a double knot
around the force meter, and then
pulled until it broke.
All the tests had similar points of
breaking, but different physical
appearances after 24 hours of drying.
Chart of Test Results
Brand A
Brand B
Brand C
Hair w/ water
Hair w/ nothing
Test 1
3.03
3.35
3.13
3.06
2.92
Test 2
1.2
1.2
1.2
1
1.2
Test 3
1.4
1.4
1.4
1.2
1.2
Mean
1.876667
1.983333
1.91
1.753333333
1.773333333
SD
1.003809
1.187785
1.061273
1.136016432
0.993042463
CI
1.135896
1.344081
1.200921
1.285499988
1.123712684
The Amount of Force to Break Each Strand
3.5
Amount of Newtons
3
2.5
2
Series1
1.5
1
0.5
0
Brand A
Brand B
Brand C
Hair Weaves
Hair w/ water
Hair w/
nothing
Brand A Shampoo
Brand B Shampoo
Brand C Shampoo
Water
Water
Water
Ammonium Lauryl Sulfate
Sodium Laureth Sulfate
Sodium Laureth Sulfate
Ammonium Laureth Sulfate
Cocamidopropyl Betaine
Dimethicone
Sodium Chloride
Sodium Chloride
Cocamidopropyl Betaine
Cocamide Mea
Fragrance
Distearyl Ether
Glycol Distearate
Glycol Distearat
Cocamide Mipa
Dimethicone
Dimethiconol
Sodium Chloride
Ammonium Xylenesulfonate
Glycerin
Behenyl Alcohol
Citric Acid
Carbomer
Laureth-2
Fragrance
Guar Hydroxypropyltrimonium Chloride
Pyrus Malus Extract/Apple Fruit Extract
Panthenyl Ethyl Ether
TEA-Dodecylbenzenesulfonate
PPG-5-Ceteth-20
Panthenol
PPG-9
Fragrance
Polyquaternium-10
Tetrasodium EDTA
Sodium Methylparaben
Sodium Citrate
TEA-Sulfate
Carbomer
Sodium Benzoate
DMDM Hydantoin
DMDM Hydantoin
Disodium Edta
Citric Acid
Niacinamide
Peg-7M
PEG-45M
Pyridoxine HCI
Cetyl Alcohol
Methylchloroisothiazolinone
Guar Hydroxypropyltrimonium Chloride
Methylchloroisothiazolinone
Methylisothiazolinone
Citric Acid
Methylisothiazolinone
Mica
Saccharum Officinarum/Sugar Cane Extract
Titanium Dioxide
Methyl Cocoate
Yellow 5
Linalool
Yellow 6
Sodium Cocoate
Butylphenylmethylpropional
Citrus Medica Limonum Peel Extract/Lemon Peel Extract
Camellia Sinensis/Camellia Sinensis Leaf Extract
Results
 After testing, it seemed that Brand B
shampoo worked the best because, on
average, the weave that used Brand B
shampoo needed the most force to break.
 On test 2 and 3 especially, all the weaves
had very similar results. However, all the
results ended up being extremely close.
Conclusion
 If someone uses a shampoo that contains
certain ingredients, then it may make their
hair stronger or weaker.
 The hypothesis was not supported because
the results were all very similar, and
there was not a huge difference.
 To improve the experiment, the shampoo
should have soaked in the hair for a longer
period of time, it should be dabbed to
remove excess water, and the hair should
have been hung to dry rather than laying it
flat.
Works Cited
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"Better Hair through Chemistry." Exploratorium. Exploratorium, n.d. Web. 29
Nov. 2009. <http://www.exploratorium.edu/exploring/hair/hair_2.html>.
Goins, Liesa. "The Science of Shampoo: What the Ingredients Mean.“
Newsweek. N.p., 8 Oct. 2009. Web. 29 Nov. 2009.
<http://blog.newsweek.com/blogs/thehumancondition/archive/2009/10/
08/the-science-of-shampoo-what-the-ingredients-mean.aspx>.
"Hair Growth- Hair Construction." Hairfinder. N.p., n.d. Web. 29 Nov. 2009.
<http://www.hairfinder.com/hairquestions/hairgrowth.htm>.
The Beauty Brains. "What is Hair Made of." The Beauty Brains. N.p., 18
Apr. 2006. Web. 29 Nov.
2009.<http://thebeautybrains.com/2006/04/18/what-is-hair-made-of/>.
"What Makes Your Shampoo and Conditioner Work for You?" iVillage.
iVillage Ltd, 2010. Web. 13 Jan. 2010.
<http://www.ivillage.co.uk/beauty/haircare/
colours/articles/0,,547397_183507,00.html>.
"Your Hair." Kids Health. Nemours, n.d. Web. 29 Nov. 2009.
<http://kidshealth.org/kid/htbw/hair.html>.