Looking into the factors affecting tensile
There will be a positive change in tensile strength (ts) in blonde hair and black frizzy hair of similar thickness. Blonde hair will have a higher tensile strength (ts) than dark hair the moment at identical thickness. Blonde hair has more sulphur-sulphur covalent bonds than black frizzy hair. Hair contains the protein keratin, which is made up of a large proportion of cysteine with S-S bonds. The disulphide connection is one of the best bonds well-known anywhere in mother nature. The cross-linking by disulphide linkages between the keratin chains accounts for much of the strength of hair.
Blonde hair has more of these you possess therefore brunette hair may have a higher tensile strength (ts) and flexibility levels.
There will be no difference in tensile strength between dark hair and blonde locks of identical thickness. Golden-haired hair having more sulphide bridges will not likely mean that blonde hair includes a higher tensile strength (ts) than black hair.
Frizzy hair has a high tensile strength. It might hold up 60kg of excess weight before disregarding.
This high strength is caused by its composition.
Hair is manufactured out of the fibrous protein keratin. Figure 1 shows keratin molecules contain three helices. They are held together by strong covalent bonds called sulphur you possess. Eleven of those molecules group together to form a micro fibril. Then, numerous micro fibrils join together to form a single hair.
Curly hair is made of skin cells called epithelial cells which are arranged in three tiers. The inner the majority of layer is definitely the medulla, the middle layer is the cortex and the out level is the cuticle. The medulla is mainly gentle keratin plus the cortex and cuticle are mainly hard keratin. This framework has superb strength. The cuticle, the outermost part, is where you find a large amount of the proteins keratin. The cortex is definitely the thickest central layer, featuring strength and defining color of curly hair. The cortex also provides the hair the elasticity and flexibility. The medulla, central core, gives frizzy hair its strength and width.
The structure of keratin is taken care of by many sulphur to sulphur covalent bonds. Keratin contains large concentrations of the amino acid cysteine.
Every Cystine unit includes two cysteine amino acids in different chains which may have come to lie all around each other and are also linked collectively by two Sulphur atoms, forming a very strong chemical substance bond termed as a disulphide link. Many disulphide bonds type down the entire keratin organizations, joining them together like the rungs of the ladder. The disulphide connect is one of the best bonds known anywhere in mother nature. This cross-linking by disulphide linkages between your keratin stores accounts for much of the strength of hair. The right amount of Sulphur Connect is important in enhancing the elasticity of hair due to the strength of the disulphide connect.
Within each hair bonds of a diverse kind, referred to as hydrogen bonds also website link the keratin chains. There are far more hydrogen bonds than disulphide entrave. The hydrogen bonds are much weaker compared to the disulphide linkages and more conveniently broken, and provide hair the flexibility. Hydrogen bonds will be broken a part when the locks is wetted, and contact form again if the hair dries.
Hair employed for the research must not be ‘damaged’ in any way, i actually. e; really should not be dyed/coloured, permed, straightened, etc . The hair also must not be curly. I will be only looking at obviously straight curly hair for this investigation.
Permed and dyed frizzy hair cause serious damage to locks by reducing and breaking disulphide bonds between necessary protein amino acids (which keep the locks strong) and they change the chemistry of frizzy hair by modifying the protein saturated internal framework of the fiber. In perming, a mild minimizing agent can be used to break the sulphur you possess. The helices are unwound and the locks is styled. A gentle oxidising agent (usually hydrogen peroxide) is treated to the frizzy hair to make the sulphur bonds change. This ends in a ‘permanent wave’. (Figure 3 displays the breaking and changing of sulphur-sulphur bridges can produce permanent modifications in our shape of protein molecules). Permed hair offers only 90% of the original disulphide a genuine, which leaves hair less strong than before it was permed.
Temperature (like by hair straighteners) disrupts the structural provides (particularly fragile Hydrogen bonds) enough to offer hairs wounded around a tool some temporary curly factor. However , this kind of effect could be easily abolished by a rise in humidity or perhaps contact with normal water. Longer lasting permanents use chemicals such as thioglycolic acid to disrupt the disulphide bonds.
Hairs to be tested with should not have their disulphide bonds damaged/broken or perhaps our hypothesis will become incorrect even before the investigation happens.
To Control¦(keep the same)
Curly hair MUST NOT be:
Tensile strength (ts) (masses applied to hair)
Thickness of hair/colour of hair
straightened (by applying heat)
permed (by applying heat)
from the same person
Frizzy hair MUST be:
dark-colored or brunette
from the same age group
2 By Clamp stand ” to support everything straight
2 Back button Clamp ” to hold paperclip/hair and ruler
100cm ruler ” to measure what lengths hair expands before that breaks (tensile strength)
a couple of X paperclip ” to hold hair and mass
10kg masses with holder ” to put pressure on frizzy hair
Selotape ” to hold trap of hair in paperclip
15 components of black hair ” to compare
12-15 pieces of blonde hair ” to review
Micrometer ” to evaluate hair width
1 ) I will 1st take five pieces of curly hair randomly via six different people. Three of those people needs to have black curly hair and 3 should have blonde hair. My personal total amounts of hair needs to be fifteen grayscale fifteen golden-haired. Hair examples should be extracted from six differing people to make sure that a reasonable and correct test happens. For example in the event that all twelve to fifteen black hairs were extracted from the same person, it could only mean that that individual had thicker hair than normal thickness of black hair. This will make my own results invalid. I will consider all hair from the same age group (my age group, 17-18), to remove the ‘age of curly hair follicle’ adjustable when comparing the tensile strength.
installment payments on your I will set up the micrometer to measure each curly hair thickness by simply placing locks under contact lens and calculating its density using a shown scale. Let me record every thickness in an appropriate desk.
3. I will place a dark hair and a golden-haired hair of similar thickness side by side. This will likely be done to compare tensile strength (ts) of hair of identical thickness.
4. Equipment will be set up as shown in Figure your five, (below) to start out investigation. The head of hair will be cautiously put in. The meter rule should be touching the bottom with the clamp stand with 0cm at the top and 100cm at the bottom. I need to guarantee the hair are unable to slip out of the paperclip above the bottom or the top. Everything has to be secure. The length of the cycle of locks formed ought to be similar much like all hairs being tested. The excess weight should not be added until the rest of the equipment has been set up effectively.
5. When the hair is set up in with the apparatus, I will evaluate how far over the hair is on the colocar rule. (Look at Physique 4, for assistance). Let me record this reading in a table similar to Table 1 )
6. Quite a few 10kg will probably be placed on the paperclip in the bottom only following first measurements have been used.
7. I will add the masses slowly thus when the hair breaks I have a better view of the length of the hair.
almost 8. When I see the hair break I will record its optimum length during my table and the weight in kg applied on hair at that point, when it come to its optimum elasticity.
on the lookout for. I will continue doing this whole procedure for all the golden-haired hairs plus the black hair. I will the actual hairs of similar fullness after one another. For example; a blonde curly hair of thickness x can be measured initial than a dark hair of thickness by would be assessed.
There will be half a dozen people in my group including me. Each person will check five fur each.
length bfr T app
span bfr breaking
length stretched bfr breaking
max W app bfr breaking
(cm) 2 without 1
Let me use the t-test because I am buying difference of tensile strength in black and brunette hair. I will be using genuine measurements (e. g. weights), and will possess a large data set (30 pairs of data). My spouse and i am comparing two pieces of data.
Investigating the elements affecting tensile strength (ts) of human being hair
Applying: (Skill B)
5. Four different colours of hair need to be used; to enhance range of results and to make my own conclusion more reliable.
Ginger, Blonde, Black and Dark brown hairs will be used.
* 35 strands of hair will be used for each colour. 5 hair from 6 people for each shade will be considered.
* A great eyepiece graticule will be used to measure hair thickness. Comparable thickness of hairs will probably be compared.
2. Girls’ hair will be used. You will discover two reasons for this:
a) Girls have got longer locks
b) Bodily hormones may have an effect on hair durability. Girls and boys may possibly have different human hormones.
* There ought to be a 10cm (100 mm) gap among each paperclip. (Figure 5).
* A 10g weight must be used every time.
* Let me need to alter my Hypothesis and Null Hypothesis mainly because instead of assessing just two colours of hair My spouse and i am today comparing several different colours of hair.
You will see a difference in tensile strength between brown, jaunatre, ginger and black fur of related thickness. Blonde hair (lighter coloured hairs) has more sulphur-sulphur covalent you possess than dark hair (dark coloured hairs). Hair provides the protein keratin, which consists of a large proportion of cysteine with S-S bonds. The disulphide connect is one of the most powerful bonds well-known anywhere in character. The cross-linking by disulphide linkages between your keratin organizations accounts for much of the strength of hair. Lighter coloured frizzy hair has more of the bonds therefore lighter colored hair will have a higher tensile strength (ts) and elasticity levels.
It will have no big difference in ultimate tensile strength between brown, blonde, ginger and dark hair of similar fullness. Lighter girl hairs having more sulphide bridges will not mean that less heavy coloured fur have an increased tensile strength then dark girl hair.
5. Now that We am certainly not comparing merely two models of data I could no longer the actual T-Test. I actually am comparing four models of data. My data will be categorical. There is a simple statistical test which usually looks at the between observed and expected values and relates these to a probability level, as a result making it possible to determine how probably it is the values are significantly diverse. This evaluation is called the Chi squared test.
Safeguards to ensure stability
* Our company is assuming cultural background will not affect the results. It will not cause a massive variation within our conclusion.
2. All locks samples should be taken from 16-18 year old females.
* 6 different samples must be considered for each coloring of curly hair.
* Make sure all equipment is set up; making sure the strand of hair is fastened to the shown equipment correctly. (Figure 5).
* Every hair can be tested 5 fold, so I i am repeating the experiment, to create my results reliable plus more accurate.
(My individual (raw data) results will be highlighted in dark red on tables two, 3, four & 5).
(The notice ‘B’ is employed in my results to show where the hair broke).
Investigating the factors influencing tensile strength of human hair
Analysing: (Skill C)
Strength depends upon the amount of anxiety a locks can endure without breaking. To work out the effectiveness of each locks I worked out the stress put on each when breaking. To perform all the measurements I utilized the following formulations:
1 . Force (N) = Mass (g) X zero. 001 By 9. 8
E. g. 10 back button 0. 001 x 9. 8 sama dengan Force (N)
Force sama dengan 0. 098N
2 . Mix Sectional Location (Ã¯m2) sama dengan? r2
Elizabeth. g. three or more. 14 back button 26 back button 26 sama dengan Cross Sectional Area (Ã¯m2)
Cross Sectional Area sama dengan 2122. 64Ã¯m2
3. Tension (Nm-2) = Force (N) / (Cross Sectional Region (Ã¯m2)/1000000)
Elizabeth. g. zero. 098 as well as (2122. 64/1000000) = Stress
Stress = 46. 16892172 (Nm-2)
four. Strain = Extension (mm) / Initial Length (mm)
E. g. 32 as well as 100 = Strain
Strain = zero. 32
The tables upon pages 18 to thirty eight show how I calculated my personal values to complete the record test.
Melanin molecules are proteins, which are made at the root of every hair. The greater melanin in your hair, the darker it will get. An amino acid known as tyrosine can be converted into melanin so the locks will have color. First, your body’s blood vessels take tyrosine to the bottom of every hair hair follicle. Then, through this ‘melanin factory’ tyrosine is utilized as the raw material for the production of the organic melanin which is colour in hair. In short, natural frizzy hair colour is dependent upon the presence, amount and distribution of melanin, an all-natural pigment present in the bande.
All natural curly hair colours are manufactured from two styles of melanin.
Eumelanin = black pigment
Pheomelanin = red/yellow color
Mixed melanin’s = when ever both eumelanin and pheomelanin mix collectively inside 1 melanin granule.
The all-natural colour in the hair is decided by:
a) What type of melanin is in the curly hair
b) How much melanin is in the hair
c) How carefully packed or scattered the melanin is within the emballage.
The type of melanin and the size of the lentigo determine whether hair will probably be brown, brunette, ginger or black. The amount of melanin as well as its distribution determine how dark or perhaps light the head of hair colour will probably be.
Black hair is created coming from granules packed with eumelanin thick in the hair’s cortex.
Brown hair, based on its awesome or nice tones as well as darkness or perhaps lightness, is done either from granules stuffed with eumelanin and even more sparsely allocated along the bande than those of black frizzy hair, or lentigo filled with different mixed melanin’s. The red/yellow pheomelanin is believed to cause the nice, golden, or auburn colors found in many brown frizzy hair.
Blonde hair has a really low melanin content. And while researchers have not however determined which is dominant, it really is believed that eumelanin produces blonde frizzy hair. Melanin in blonde frizzy hair is so thinning that what we should actually observe is the shade of the hair fibre by itself, keratin, the pale yellow, off-white hue.
Granules filled with pheomelanin make Ginger curly hair. The pheomelanin in turmeric hair is much less densely packed in the granules. It is shape can be somewhat even more irregular than its dark counterpart, eumelanin. It is a little bit rounder plus more spread out.
Via my outcomes I found away that dark brown hair required the greatest amount of pressure to break. Blonde hair necessary the least quantity of force to break. Dark hair was second strongest and turmeric hair was third best. The buy of power (from my results) of hair is as follows: Darkish, Black, Turmeric, and then Golden-haired.
Brown curly hair stretched the most before breaking. Blonde frizzy hair stretched the least before breaking. Black frizzy hair stretched the other furthest and ginger frizzy hair stretched the third furthest. The order of length of frizzy hair stretched (from my results) before breaking is as comes after: Brown, Dark-colored, Ginger, and after that Blonde.
Darkish hair experienced the highest tension before breaking and golden-haired hair experienced the lowest pressure before breaking. The purchase of tension experienced by simply hair (from my results) before breaking is as employs: Brown, Black, Ginger, then Blonde.
Brown hair experienced the highest tensile stress value before disregarding and brunette experienced the minimum tensile pressure value just before breaking. The order of tensile stress experienced simply by hair (from my results) before breaking is as comes after: Brown, Ginger, Black, and then Blonde.
Chart 1 reveals the average pressure required to break the 4 colours of hair. From this graph I am able to see that brown hair essential the greatest power to break. Dark hair as well required a great deal of force to break and so did ginger locks. Black curly hair only necessary a small amount of more force to break then ginger hair. The breaking force required for brownish, black and ginger hair was quite comparable. Blonde curly hair required a lot less force to break compared to the other colours of hair. This proves which the disulphide a genuine in the blonde hair are certainly not a big advantage for strength of the hair. The darker the head of hair the more robust the power required for the bonds inside the hair to break. The darker the hair the greater resistant you should breaking the moment forces will be applied. The darker the hair the higher concentrations of melanin present along the hair cortex.
The same kind of pattern is observed in charts 2, several, 4 and 5. Graphs 2, several, 4 and 5 show the extension of hair once masses happen to be added. Brunette hair destroys the earliest and brown hair breaks the latest.
Graph 2 shows brownish hair. Brown hair needs about 120g to extend up to about 70mm before breaking. The chart follows a basic trend and there are no anomalous results. Every results fit the line of best fit.
Graph 3 displays blonde frizzy hair. Blonde hair requires regarding 80g to increase up to regarding 35mm just before breaking. The graph comes after the basic craze and most outcomes fit the queue of best suit. There is a single anomaly, though. The extension should not increase after which decrease. It should keep on reducing. There must have been an error in recording this kind of result. The results in graphs 2, three or more, 4 and 5 are typical averages. To exercise the golden-haired values in table thirty-two, the ends in tables doze, 13, 16, 15, 16 and 17 were utilized. There was only one value for the extension at 80g, in table 15. This worth was less space-consuming than the average of all of the extensions in most six tables. This test of hair should have broken at 80g not 90g. This would not happen. This might have been an error in not measuring effectively.
Graph 4 shows turmeric hair. Ginger hair requires about 100g to extend about about 60mm before disregarding. The graph follows the standard trend until it gets to 55g point. From this point onwards the hair length boosts and decreases dramatically. This should not happen. The reason why this kind of happens is described over with the blonde hair. Costly error in measuring.
Chart 5 displays black locks. Black hair requires regarding 140g to extend up to about 65mm just before breaking. This graph is perfect. There are zero anomalies. All points meet the brand of best fit effectively.
Graph 6 shows the average stresses and strains knowledgeable by each hair coloring. All four locks colours happen to be plotted on a single graph so they can be easily in contrast against each other. Brown, golden-haired and ginger hairs tend not to follow the usual trend. The stresses and strains for the three should continue to maximize. Tables 57, 58, fifty nine and 70 show the place that the stress and strain beliefs came type. The the desired info is like this since when the tension and stress values were calculated the typical extensions had been used, which had a handful of faults, because describe above.
Graphs several, 8, 9 and 12 show evidently what is happening towards the stress-strain curves. Graph 7 shows a single anomalous consequence. It has a high stress and strain benefit. Graph 8 also shows only one anomalous result. The two of these graphs show the basic trend. Graph on the lookout for shows the conventional trend before the stress benefit gets to 150Nm-2. Then it reduces and dates back on by itself. This should not happen. The reason for this can be explained previously mentioned. There is an error in the file format averages. Chart 10 displays no particularité.
Graphs eleven, 12, 13 and 16 show customized values to get stress and strain in all colours of hair. Graph 11 shows the customized stresses and strains for brown curly hair. This graph does not bend over backwards plus the stress and strain principles do not reduce. Graph doze shows the modified strains and stresses for blonde hair. This graph will not show principles of pressure and stress decreasing. Chart 13 shows the customized stresses and strains intended for ginger locks. This graph has changed a whole lot. It scans much clearer. Stress and strain boosts throughout. This is just what the chart should seem like. Graph 13 is the same as chart 10. This did not want any alterations.
The durability of a locks is assessed of the resistance to break. A lot of energy is required to break a tough material. Finally, the strength of a material (or ‘tensile strength’) is the best tensile tension it can undergo before breaking.
Hair is usually an stretchy material; it could stretch to some maximum point (elastic point) before disregarding. The largest tensile stress that could be applied to a material ahead of it fractures is known as it is ultimate tensile stress (UTS). This benefit is sometimes called the elements breaking stress.
Graph six shows the stress-strain factors for brownish hair. Graph 11 shows a altered version on this. The UTS for brown hair can be 359. 03. Graph almost eight shows stress-strain points pertaining to blonde curly hair. Graph doze shows a modified version of this. The UTS pertaining to blonde frizzy hair is 125. 48. Graph 9 displays the stress-strain for ginger hair. Graph 13 displays a revised version of this. The UTS for turmeric hair is usually 286. 58. Graph 15 shows the stress-strain items for black hair. Chart 14 reveals a altered version of this. The UTS for dark-colored hair is 158. 23.
Overall I could see that brownish hair was the strongest. This was not expected. I expected dark hair to have the highest tensile strength, as it a new higher thickness of melanin along the bande. Blonde hair turned out to be the one with the cheapest tensile anxiety. Ginger haired people have a top density from the pheomelanin pigments in their curly hair fibre. Individuals who produce virtually no eumelanin have a crimson to orange colored colour depending on the density in the pigment inside the hair fiber. Red haired people who have the relative portion of eumelanin production possess a much deeper red to red brownish colour. Ginger hair also should have a higher tensile strength. This is just what I saw inside my results. Black hair should also have a top tensile strength. My own results demonstrated black frizzy hair to have large tensile strength although not the highest.
There are other ways by which hair tensile strength could have been tested. Hair goods like shampoos have an effect on hair tensile strength. Vehicle designed to transform hair strengths. Different makes of locks shampoos could possibly be used. Power could be scored in a similar way to how I tested it. A control will be also be necessary, with frizzy hair with no goods added.
These modifications in Graphs 11, 12, 13 and 13 show the particular stress tension graphs will need to look like. In Graphs several, 8, being unfaithful and 15 the
lines should not flex backwards.
I am using the (Chi squared test) X2.
The formula to get the Chihuahua squared test out is as comes after:
X2 =? [(O ” E) 2 /E]
Um = Discovered value
Electronic = Anticipated value
The ((O ” E) 2) part of the solution considers how big the difference between the observed and expected values. This big difference could be either positive or negative. To prevent the mathematical problems associated with negative values, the difference is usually squared.
The (E) portion of the formula corelates the size of the to the degree of the quantities involved.
The sigma (? ) ‘sum’ symbol is essential because there is not just one pair of observed and expected ideals, but several (in the case four).
Through all the discovered values of stress via tables 57, 58, fifty nine and 60, I can exercise the predicted value for each hair colour.
I can then place these values in a table and work out the worth for X2, using the chihuahua squared solution.
E = ( OBrown + OBlonde + OGinger + OBlack ) as well as 4
E = ( 297. a few + 121. 5 & 246. several + 158. 3 ) / some
E = 205. 95
205. ninety five
205. ninety five
( U ” Elizabeth )
( O ” E ) 2
(( O ” E ) 2) / E
thirty four. 629
almost 8. 063
X2 = forty. 519 + 34. 629 + almost 8. 063 & 11. 025
X2 sama dengan 94. 235
To estimate the examples of freedom being used is available as follows:
* Number of categories minus 1 )
In this case: 5 ” one particular = 3
The critical value (taken from critical values to get the Chi squared test) at 3 degrees of freedom is several. 81 (at the five per cent level).
Quality statistic (X2 = 94. 235) is greater than the critical value
(C. Versus = six. 81, in the 5% significance level). We therefore can easily reject the null speculation and point out there is a factor between the noticed a
Looking into the elements affecting tensile strength of man hair
Considering: (Skill D)
2. The selotape holding hair in the paperclip at the top and at the bottom could have interfered while using tertiary composition of the healthy proteins, keratin. This may have improved or reduced the bond attractions in the hair to cause the head of hair to have a excessive or low tensile stress. This would produce my results unreliable. The hairs exhibiting higher tensile stress may just be showing how sticky the selotape is and how strongly it is keeping the hair composition together. This though, would affect my results, since all curly hair samples experienced selotape on them to hold these people together towards the top and at the bottom. So , this limitation will affect almost all hairs which makes it a very fragile limitation. My conclusion will never be affected because this limit affects most hairs.
* The time in the middle weights had been added is yet another limitation. Once each excess weight was added the hair expanded. But when there was a lot of weights on hair, the head of hair stretched quickly and then the length was assessed. After I finished measuring the head of hair had little by little stretched a bit more. So the way of measuring was incorrect. When the up coming weight was added extra extension was added onto the newest extension. My own results were afflicted with this since some plug-ins were phony making a lot of data imprecise. Therefore , my own conclusion will probably be invalid, since some curly hair samples would have broken in lower weights if I got waited to get the hair to stretch, incredibly slowly until it broke. Presently there needed to be a moment limit by which I had to record the extension of the hair, before adding the next weight to the locks.
* The attention piece graticule can be a limiting factor. Differing people measured frizzy hair thickness and recorded this to what that they felt the thickness needs to be according to the scale. It was not too clear to see just how thick the hair was, as the hair was faded within the microscope in any way magnifications and the outline was difficult to observe. This could impact my effects as the thickness of hairs was used to estimate the combination sectional area of the hairs, that was then accustomed to calculate the tensile tension experienced by hair. This may make my tensile pressure values wrong. My realization therefore could be affected; by looking into making out a certain coloured hair had a higher tensile stress than another colored hair, once really this shouldn’t have got. This would generate my bottom line unreliable.
* There were several shades of curly hair colour, for example , there were lumination brown locks colours and dark brown hair colours. It absolutely was sometimes hard to distinguish between brown and blonde. It was the same for blonde curly hair. This would come with an affect around the reliability and precision of my outcomes making the accuracy from the strengths of various colours of colors of hair inaccurate. Presently there should have recently been a certain tone of color of curly hair (same amount of melanin in each brown hair) used for each colour test. My summary will be imprecise because brownish or golden-haired hair colours could cause wrong results and make my own conclusion incorrect.
* The 10g mass is a limitation as the head of hair could break at decrease masses than they actually do, for example a hair that broke in 50g would have broken for 41g, yet I more than likely know that?nternet site only used 10g world. So , I acquired false blood pressure measurements implying the hair is more robust than it really is. If smaller masses were used my results would be much more appropriate to make my own conclusion trustworthy. This restriction could cause my own conclusion to become invalid, leading to the hair strength and point about breaking larger or less than it actually is.
After carrying out my statistical test I am able to reject my own null speculation and recognize my speculation and declare brown, brunette, ginger and black fur differ in tensile strength. I have proved this difference inside my calculations, generally in graphs 1 and 6. By my benefits I can see that darker girl has a higher tensile pressure compared to lighter weight coloured hairs. In my hypothesis I said that lighter female hair could have a higher tensile strength than deeper coloured hair, due to less heavy coloured frizzy hair having sulphur-sulphide bonds, which are very strong. I have disproved this kind of. Through screening all four shades of hair I can notice that these good sulphur you possess do not reveal any tensile strength (ts) qualities. Less heavy coloured frizzy hair does not have an advantage over dark girl hair in terms of tensile strength. That mainly depend upon which type of melanin the hair contains. The denser the melanin quantity may be the stronger the head of hair.