General Level. 1) A minimum of six shampoos. Only a few drops of each shampoo are needed.

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General Level

“And even the very hairs of your head are all numbered.” (Matt. 10:30) Notes: The experimental section requires:

1) A minimum of six shampoos. Only a few drops of each shampoo are needed.

2) Full range (pH 1 to 14) Universal Indicator solution or paper.

3) Test-tubes or e.g. a small clear glass jar.

4) Cooking oil (any brand): a few cm³ are sufficient.

5) Distilled or deionised water which is obtainable from most car part outlets. (See note after the results table.)

6) Dropping pipettes or any way of adding a drop or drops of shampoo.

7) Petri dishes (apparatus may be bought from: www.Timstar.co.uk)

The material below has been derived from Royal Society of Chemistry resources for teachers.

This project has three parts, a shampoo user survey and two experiments. The first experiment is to measure the pH values the shampoo to decide which shampoos have ideal pH values. The second experiment involves measuring the diameter of surfactant produce from one drop of shampoo in order decide the best shampoo for cleaning hair.

Part 1 – Aim: To Carry Out A Shampoo Use Survey

The look and style of hair is a major pre-occupation amongst young people. A great deal of money is spent in having haircut, styled, coloured, treated and kept clean.

The companies that manufacture shampoos use a specific brand name but under that brand name are various types of shampoo since people have different types of hair. (Include “dandruff”, in the same column as hair type.) All information collected should be put in the survey table and then six questions answered.

The questions you need to ask a minimum of ten people are:

1. Which brand and type of shampoo do you use?

2. Why do you use this shampoo?

3. The cost of the shampoo (The cost per 100 ml is required and this can be found online.

No calculations of actual shampoo costs per 100 ml need be shown).

Also determine a person's type of hair.

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Survey table Cost units need to be included.

Participant’s name Brand name and type of shampoo used

Cost / 100ml

Hair type in words

Reason for shampoo choice

Survey questions: The questions don’t need to be typed out if the answers make the questions obvious.

1. Which is the most common type of shampoo used by people in your survey?

2. Which is the most common type of hair reported in the survey?

3. Choose two people from the survey with different types of hair and explain why the shampoo they use matches their hair type?

4. State two reasons, other than matching hair type, that people give for buying a shampoo.

5. Why might it be important to pick a shampoo which matches hair type / condition?

6. Find the average cost /100 ml of the shampoos listed in the survey. (Each shampoo of the same brand, type and cost should be considered once only)

Dandruff

Dandruff is thought to be caused by yeasts, which live naturally on the skin. When they grow too much, they cause irritation on the skin. The skin reacts by shedding cells more quickly and too soon which fall off as tiny flakes we call dandruff. The best anti-dandruff shampoos (medicated shampoos) include certain chemicals which work on the hair, for example: a ‘fungicide’, e.g. zinc pyrithione to control the growth of the yeasts, and a ‘keratolytic’ chemical to help wash away the skin flakes, e.g. salicylic acid.

Acidity and shampoos

pH is a measurement of the degree of acidity of an aqueous solution. The pH range is from pH 0 (very acidic) to pH 14 (very alkaline). Neutral pH (neither acidic nor alkaline) is exactly pH 7.

Acidity is due to hydrogen ions (H⁺) in aqueous solution. The greater the concentration of hydrogen ions the greater the acidity and the lower the pH of that solution.

The pH increases by a factor of 10 for everyone unit decrease in pH; pH 5 is 10 times more acidic than pH 6 and pH 1 is 100,000 times more acidic than pH 6. Above a pH of 7 it is better to use, “more or less alkaline,”

thus a pH of 9 is ten times more alkaline than pH of 8.

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The colour of the Full Range Universal Indicator solution varies with the pH of the solution into which it is introduced. The solution colour is compared with the colours on the pH card and the pH found.

Electronic instruments called pH meters are also used to measure pH values. These can be highly accurate instruments capable of measuring the pH to 0.001 pH units.

The acidity of hair (and skin) usually varies from about 4 to 6. The ideal pH level for a hair product should be slightly acidic, in the pH range of about 4 to 6. (Some sources give a slightly different ideal pH range.) Most of the surfactants / detergents in shampoo produce alkaline solutions so many shampoos contain weak acids to lower the pH to a slightly acidic value. The pH of distilled water is 7. Extreme pH values of shampoos can be harmful to hair.

Part 2: Two chemical tests and the action of some shampoo ingredients Aim: To find out which shampoos have ideal pH values in the pH range 4 to 6 Variables:

Name the independent variable in this experiment. (The factor that is changed during the experiment and investigated.)

Name the dependent variable in this experiment. (The factor that is measured or observed during the experiment on which the independent variable depends.)

Name the controlled variables in this experiment. (The factors that are kept constant throughout the experiment.)

There may also be extraneous variables – variables that cannot be controlled and that influence the outcome of the experiment. These can be ignored.

Prediction: see ‘Prediction’ on page 5.

Safety

Universal indicator: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. Skin Contact: IF ON SKIN (or hair) remove/take off all contaminated clothing immediately. Rinse skin with water/shower. Remove contact lenses.

Shampoo in the eye. Flush it. Rinse your eye with cool water right away for at least 15 minutes. If you wear contacts, take them out, but don't stop rinsing your eye while you do it.

Keep bottles and glass wear away from the edges of the table so they are less likely to be knocked off.

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Apparatus and chemicals (Supervision is required)

• Full range Universal Indicator solution or paper and pH colour chart or pH meter

• Water (distilled or deionised is preferable). See the note after the results table

• Test tubes

• Dropping pipette

• Protection for clothes

• Six shampoo samples of known brand and type

• Eye protection is essential.

Method: Remember to wear eye protection

Put some water in a test-tube and add two drops of Full Range Universal Indicator. Mix thoroughly (If the colour of the solution looks too pale add another drop or two or indicator). Take and record the pH value to the nearest half a pH unit. Repeat once and a second time if the pH values are different (Adjust the method if using Universal Indicator paper or pH meter). Average the pH values to the nearest half a pH unit.

1. Put one drop of the shampoo in a test-tube and add about the same volume of water as used previously. (The same volume of water can be estimated.)

2. Add two drops of Full Range Universal Indicator solution and shake the tube gently to mix (Adjust the method if using Universal Indicator paper or a pH meter).

3. Find the pH of the solution to the nearest half and record the value in the results table.

4. Repeat steps 2 to 4 twice.

5. Average the three pH values to the nearest half a pH unit.

6. Repeat steps 2 to 6 for the other shampoos.

7. Plot a bar chart of average pH against shampoo (See page 8)

Note: If the pH of the water is not 7 then a different source of water may be sought. However, suppose the pH of the water is 6 and the pH of the shampoo is e.g. 5, record a pH of 6 for the shampoo. This is because the shampoo has reduced the pH of the water by one pH unit. If the pH of the shampoo is e.g. 8, then record a pH of 9 since the shampoo has increased the pH of the water by 2 units. If this happens very briefly comment that pHs are adjusted since water pH was not 7.)

Results tables

Brand name and type of shampoo pH value

Test 1 Test 2 Test 3 Water

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Aim: To measure the diameter of the circles on the surface of oil in order to find the shampoo which is best at cleaning hair

How detergents work

Detergents “molecules” have hydrophilic (water-loving) heads and lipophilic (fat loving) tails. The tails avoid water but “stick in” greasy substances. When hair is greasy the detergent molecules in the shampoo are able to remove this grease. Their “tails” enter the grease but their “heads” remain in the water and with agitation the surfactant molecules with the collected grease containing any dirt will leave the hair and enter the water to be rinsed away. The left hand side picture is a simple representation of the surfactant on the right.

Grease loving tail Water-loving head

Variables:

Name the independent variable in this experiment (The factor that is changed during the experiment and investigated).

Name the dependent variable in this experiment (The factor that is measured or observed during the experiment on which the independent variable depends).

Name the controlled variables in this experiment (The factors that are kept constant throughout the experiment).

There may also be extraneous variables – variables that cannot be controlled and that influence the outcome of the experiment. These can be ignored.

Prediction: make one prediction about this experiment or the pH experiment. If the prediction is about the pH experiment, write it after the pH variables.

When a drop of the shampoo is carefully added to the layer of oil it appears as a blob on the oils surface. The diameter of this blob is not measured. The surfactant molecules leave the blob of shampoo and form a single circular layer of molecules on the surface of the oil with their lipophilic and lipophobic parts suitably arranged. The diameter of this circle is measured.

The above diagram shows how detergent / surfactant molecules would arrange themselves on the surface of water.

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Apparatus

• Petri dish

• Piece of dark card or paper

• Dropping pipette

• Ruler in mm or alternative way of measuring the diameter.

• Cooking oil (actual oil type is not important)

• The same shampoo samples as used in the pH tests

• Protection for clothes

• Eye protection

Diagrams

Blob of shampoo Surfactant layer

Diameter

Edge of Petri dish

Bird’s eye view Method

1. Put the Petri dish on the dark card or paper.

2. Put oil in the Petri dish to make a thin film over the base.

3. Add one drop of shampoo in the centre of the oil.

4. Watch as the surfactant spreads out and measure the diameter of the circle formed by the surfactant when it stops spreading.

5. Record the diameter in the results table 6. Repeat the experiment twice more 7. Average the diameters that are close.

8. Repeat steps 1 to 7 for the other shampoos.

9. Plot a bar chart of average diameter against shampoo (See page 8).

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Results table

Units have to be included in the table.

Brand name and type of shampoo Diameter of circle

Test 1 Test 2 Test 3

Produce and complete the following table and include the appropriate units.

Brand name and type of shampoo Cost per 100ml

Average pH value

Average diameter

Bar charts

Produce either two separate bar charts or both bar charts together of: average pH against shampoo and average diameter against shampoo.

Experimental conclusions

1. State, with a reason, which shampoos have the ideal pH values.

2. State with a reason which shampoo is best at cleaning hair?

It is not required to find a relationship average pH and average diameter.

Prediction

Explain clearly if the prediction was right or wrong.

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Critique: Questions do not have to be typed out, but clearly written answers are required.

1. The accuracy of the pH values is best judged by comparing the pH values obtained with the actual pH values found online:

• https://www.botoxforhair.net/blog/shampoos-ph-levels-list-database/

• https://www.thenaturalhavenbloom.com/2012/02/ph-of-shampoo-ultimate-list.html

• https://www.youtube.com/watch?v=skhkY8quXEA

Compare the pH values obtained with the pH values found online. Suggest one reason why any pH values differ (It is only necessary to find one pH value). If shampoos have been used and no actual pH values are available, then comment on the pH values obtained, explaining why the values are likely to be accurate or inaccurate.

2. Precision is about the closeness of repeated experimental results. Which set of three diameter values have the best precision and which set of three diameter values have the worst precision. Suggest one reason why diameters vary for a drop of the same shampoo.

Questions The questions don’t need to be typed out if the answers make the questions obvious.

1. Which shampoo is a. most acidic or b. most alkaline? Explain your answers.

2. Explain, only using the information in the previous table, which shampoo tested is the

“best” shampoo? (There may not be a definite answer to this question.) 3. Shampoo ingredients and their actions

Shampoos contain many ingredients to function. Use the Cosmetic Ingredients Database (Chem soc 0504) to identify 10 of the shampoo ingredients found in shampoos that have different actions. One example is provided:

Shampoo Ingredient Action of Ingredient

Methylchloroisothiazolinone Preservative

Final comments on the project

What have you gained from carrying out the “Shampoo Project”

This concludes the requirements for the ICCE General Level Science Project.

The requirements for the ICCE Intermediate Level Science Project follow on page 10.

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The Report (suggested order)

“Aim for Excellence”

1. Front page with name, title of project and student ICCE number.

2. Contents page.

3. Brief introduction to the project: this outlines what the project is about in a clear, concise manner.

4. Background information. About 1 page can get full credit: 2 pages at most is sufficient. Thus, all suggestions are not required. Choose wisely. Suggestions: History. Hair cleaning products. Types of hair. How shampoo works.

Dandruff. What is shampoo? Shampoos & pH values. Some types of shampoo. Soap. The background

information should not be directly copied and should be well-structured (without repetition) and appropriate to the project level.

5. Survey: In the report prior, to the survey table, how the information was obtained and recorded are required.

Other information should be included which would be helpful to whomever is about to read the information on the table.

6. Experimental sections: Aims, the science behind the experiments, variables, prediction, requirements for the experiments (name only what was used), detailed methods, results tables, bar charts, conclusions, prediction comment, critique, and questions (keep to the same numbers).

Methods should say, all that was done and how it was done, e.g. the instruments used should be stated. The past tense (was and were) should be used in the third person, so do not use personal pronouns. Methods are written in continuous prose, not in lists. A good method is so detailed and complete that it lets someone else duplicate your experiment exactly! Include an appropriate fully labelled diagram/picture/photo where it helps to make the method clearer. Do not draw diagrams of each piece of apparatus. A diagram may be drawn in pencil or be computer generated.

The results table should have units in the headings of the table and not on every line.

Calculations: It is not necessary to show the numbers being used in the calculations provided the formulas used are provided. If the formula is unknown then one example of the calculation is sufficient. If the results contain outliers neatly draw a line through the value to show they have not been used in averaging (Formulas/workings are not required for averaging if you are sure you can average correctly).

Bar chart: must have both axes correctly labelled in words and units and a suitable heading. (May be hand drawn.) (Using text boxes are one way of labelling the axes if the “graph programme” does not.)

7. Final comments.

8. Bibliography reference should be given for e.g. direct quotes, pictures, tables of information; but it is

not needed for general information. It is not necessary to reference information sources that have been looked up and not used. It is not necessary to give the date the source was viewed.

9. Draft results: these are the results written down as the experiment and survey are being done. They

may include results that are neatly crossed out since the experiment/survey went “wrong.” A scanned copy may be supplied. Draft notes and a copy of the project are not required. Note: The experimental data can be put directly into Excel. If this is done a note should be supplied at the end of the report.

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Intermediate Level

Complete all the requirements for the ICCE Science Project General Level (you cannot use this topic if you completed it for the General Level Certificate).

All aqueous solutions consist of millions of water molecules (H2O).

The two hydrogen atoms are covalently bonded to the oxygen atom to produce one water molecule.

However not all water molecules remain as H2O; a very small number ionise into hydrogen ions and hydroxide ions:

H2O(l)



H⁺(aq) + ^-OH(aq)

In pure water at 25^oC the molar concentrations of hydrogen ions and hydroxide ions are equal to 1 x 10^-7 mol dm^-3.

pH can be expressed mathematically as pH = - log10[H⁺]. In words this says: pH is the negative logarithm to the base 10 of the hydrogen ion concentration in mol dm^-3.

When a square bracket, [ ], is used it means that the concentration units are mol dm^-3. Thus if [H⁺] = 1 x 10^-7 mol dm^-3, and pH = - log10[H⁺] pH = - log10[10^-7]. pH = 7.

[H⁺] 10^-1 10^-2 10^-3 10^-4 10^-5 10^-6 10^-7 10^-8 10^-9 10^-10 10^-11 10^-12 10^-13 10^-14 pH = - log10[H⁺] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 The pH increases by a factor of 10 for everyone unit decrease in pH; pH 5 is 10 times more acidic than pH 6 and pH 1 is 100,000 times more acidic than pH 6.

The equation pH = - log10[H⁺] means that the pH of any acidic solution can be calculated providing the hydrogen ion concentration, [H⁺], is known or can be calculated.

E.g. 1. A shampoo has a hydrogen ion concentration of 5.6 x10^-6 mol dm^-3, calculate the pH.

[H⁺] = 5.6 x 10^-6 mol dm^-3, and pH = - log10[H⁺]. pH = - log10[5.6 x 10^-6] pH = 5.3 E.g. 2. A shampoo has a hydrogen ion concentration of 6.8 x 10^-7 mol dm^-3, calculate the pH.

[H⁺] = 6.8 x 10^-7 mol dm^-3, and pH = - log10[H⁺] pH = - log10[6.8 x 10^-7]. pH = 6.2 The equation for converting a pH value to a hydrogen ion concentration is: [H⁺] = 10^-pH. E.g. 1. A shampoo has a pH of 5.7, calculate the hydrogen ion concentration.

[H⁺] = 10^-pH [H⁺] = 10^-5.7 [H⁺] = 2.0 x 10^-6 mol dm^-3

E.g. 2. A shampoo has a pH of 6.4, calculate the hydrogen ion concentration.

[H⁺] = 10-pH [H⁺] = 10^-6.4 [H⁺] = 3.9 x 10^-7 mol dm^-3

See page 18 on how to use a calculator to calculate the pH and hydrogen ion concentration.

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1. Explain clearly, using scientific terms, how a shampoo removes grease which contains dirt from hair.

2. A shampoo ingredients and their actions table was completed for 10 ingredients for General Level.

Repeat this table but add a third column and explain the action of the ingredient.

Shampoo Ingredient Action Explanation of Action

Methylchloroisothiazolinone Preservative Stops bacteria from growing growing

3. What causes most shampoos to have a pH between 5 and 6.9?

4. The pH of Garnier Fructis, Dove (Beautiful Clean) and Aubrey (Organics) are 3.4, 5.5 and 9.0 respectively.

List the three shampoos in increasing hydrogen ion concentration.

5. The hydrogen ion concentration in Tresemme (Naturals) is 2.0 x 10^-6 mol dm^-3. Show by a calculation that the pH is 5.7.

6. Calculate the pH of a shampoo with a hydrogen ion concentration of 5.0 x 10^-7 mol dm^-3. 7. Calculate the hydrogen ion concentration of a shampoo with a pH value of 6.2

8. Give one example, of what did people use to wash their hair before shampoo was invented? (If possible, make the answer relevant to your country or area).

Discussion

Finally, write a 500 word discussion on “What makes a commercially successful shampoo?”

This concludes the requirements for the ICCE Intermediate Level Science Project requirements.

The ICCE Advanced Level Science Project requirements follow on the next page.

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Advanced Level

Complete all the requirements for the ICCE Science Project General and Intermediate Level (you cannot use this topic if you completed it for the General or Intermediate Level Certificate).

(RSocChem “Hair and Shampoo – the Facts”)

Our bodies are covered with hair. Most hairs are fine, short and cannot be seen. Thick hair on our heads helps keep our heads warm. This is what we really think of as ‘hair’. Hair is not alive. Hair is made by living cells buried in the scalp, the skin on our heads. Hair is made from the protein keratin and is like nails, claws, hooves and feathers on other animals.

A B C: Hair root

A: Cross section of a hair at the root: Reproduced with kind permission from Catherine Gerst, L’Oreal Recherche, Paris, www.hair-science.com (accessed November 2003). B: Cuticle structure and C Hair bulb reproduced with kind permission from Chris Gummer, Procter & Gamble.

Each head hair is composed of three layers. In the middle is a honeycomb like structure called the medulla. This is surrounded by the cortex which forms the bulk of the hair fibre and contains the hair colour. On the outside of the hair is a thin protective layer of cells called the cuticle. It is formed from dead cells, overlapping in layers, which form scales that strengthen and protect the hair shaft. The fibres grow from a living root in a sac under the skin called a ‘follicle’.

Cells in the follicle multiply, are pushed upwards by those underneath, and fill up with keratin. They harden and then die, making a scaly coat like roof tiles over the keratin fibres. This outer coating is called the ‘cuticle’ and is also made mainly from keratin.

C

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Sebaceous glands near the base of the follicle produce an oily substance called ‘sebum’ which makes the hair shiny, keeps the scales of the cuticle flat and prevents the fibre drying out.

Sebaceous gland Sebaceous secretion

Reproduced with kind permission from Catherine Gerst, L’Oreal Recherche, Paris, www.hair-science.com (accessed November 2003).

We wash hair when it gets dirty. The dirt is from the body and the outside world. Dirt is 5% of hair mass.

Dirty hair feels sticky and unpleasant. Unwashed hair will start to smell. Some people think that hair will wash itself if left unwashed - this is not true!

Dirt from the body is made from grease and dead skin cells. Grease, called sebum, is made by glands in the skin called sebaceous glands. Dead cells come from the scalp and cuticle.

The outside world also makes our hair dirty. First, we have to wash off all the extra products we put on it - sprays, gels, muds, styling foams and conditioners. Then there is also dirt which floats on to hair as we move around.

1. What do you believe would happen to our body hair if we stopped wearing clothes?

2. What causes hair to be dry or to be greasy?

3. Would our hair be healthier if we did not use extra products such as hair gel?

Washing hair - how does shampoo work? (See page 5)

Shampoos are good cleaners. 100,000 hair fibres each 10–20 cm long give an area of 2–4 m² to be cleaned.

This is the floor size of an average room. Even so only a small amount of shampoo is needed! At least one chemical in shampoo is a surfactant. The bottom diagrams show how a surfactant works on hair. Surfactant means ‘surface active’ chemical. When the “tails” of sufficient surfactant molecules (called, “detergent molecule” on page 5) have entered grease on hair, agitation “shakes” them and the grease off the hair into the water. The grease/sebum glob and surfactants form spherical units called micelles.

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A micelle, (shown left), consists of the removed grease/sebum with the lipophilic (hydrophobic) “tails” of many surfactants “dissolve” into the sebum/grease. The polar hydrophilic heads of the surfactants being in the water. e.g. If the surfactant is sodium lauryl sulphate, the long hydrocarbon tail is in the grease and the negative polar head is in the water.

CH3CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2OSO3-

Lipophilic tail that enters the grease Polar head in water

If the surfactant is too efficient, too much natural oil will be removed from the hair and it will become dry. Makers choose surfactants carefully. Different surfactants act in different ways.

The main cleaning surfactants in shampoo are sodium lauryl sulfate and sodium laureth sulfate. The molecular structures of these two compounds are shown.

Note: The sodium ion is not involved in the removal of grease. Ionic compounds cannot have a negative ion without a positive ion. The sodium ions remain in the water.

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Sodium laureth sulfate has a longer hydrocarbon chain than sodium lauryl sulfate and is less irritating. This is probably because as a larger molecule it does not get into skin pores easily.

Different surfactants lather and clean to different degrees. A second type of surfactant is found in shampoos.

These molecules act as conditioners - they stick to the hair, making the fibres feel smooth and silky.

Shampoo makers must make sure the conditioner and shampoo surfactants do not react together - otherwise the formulation will not work.

4. Which surfactant should you look for if your skin is sensitive? Explain your answer.

5. Why do shampoos contain more than one type of surfactant?

6. What is the difference in molecular structure of the two shampoos shown on page 14.

What advantage does this extra length of structure have? Why?

Making hair manageable and shiny

Other compounds also ‘condition’ hair, e.g. ‘dimethiconol’, these contain silicon atoms. The molecules make a water-resistant coating by sticking on the hair fibre surface. When dry, silicones feel smooth and slippery;

hairdressers say this makes hair more ‘manageable’.

Hair shines when light reflects off the surfaces reflect light more evenly, giving a shiny look. To make the hair surface smooth, the cuticle scales’

must lie flat. If the cuticle scales are “roughened” (don't lie flat) light is not evenly reflected and hair will not shine. To help make hair shiny, shampoos usually have pH values of 4-6, which is slightly acidic. This is because the cuticle tiles move apart at alkaline pH, causing rough fibres.

Traditionally, hair can be made to shine by rinsing in vinegar or lemon juice.

Knot in a hair Knot in a hair, seen through a SEM Reproduced with kind permission from Catherine Gerst, L’Oreal Recherche, Paris, www.hair-science.com (accessed Nov. 2003).

7. What differences do conditioners make to hair?

8. What effect does a slightly acidity shampoo have on the cuticle scales of the hair shaft and why is this considered desirable by some people?

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Shampoo preparation

You are a researcher working for a cosmetics company and your task is to come up with a new shampoo formulation.

The following method may be used to produce a sample of shampoo which contains an essential oil and an herb extract.

Write up the method and include it in your project as if you carried out the work. Remember to include an equipment and reagent list of the equipment and reagents used.

Note: Some of these components are only available to purchase in bulk and so there is no requirement to actually produce your own sample.

Equipment and reagents you used to prepare a 100cm³ sample of this new shampoo:

• Eye protection

• 30 cm³ ammonium lauryl sulphate

• 10 cm³lauryl betaine

• 5 cm³herb extract

• 2 cm³polysorbate-20

• 0.5 cm³essential oil

• 52.5 cm³ distilled water

• heatproof mat

• glass stirring rod

• 250 cm³beaker

• Bunsen burner

• Tripod and gauze

• 10cm³, 50 cm³ and 100 cm³measuring cylinders or pipettes appropriate to thevolumes

• Herbs are on page 17

Preparation of herbal extract

Heat a handful of fresh or dried herbs of choice in 150 cm³distilled water. Boil gentlyfor 20 minutes then strain the mixture into a beaker. Keep this extract to addto the shampoo formula.

Shampoo sample preparation

Add 5 cm³of the herb extract to the 30 cm³of ammonium lauryl sulphate in abeaker and stir using the glass rod. Add 10 cm³of lauryl betaine and continue tostir. Add 2 cm³of polysorbate-20 and stir then add 0.5 cm³ essential oil and stir.

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9. What makes this shampoo different from most others?

10. Which of the ingredients is the surfactant, the emulsifier, the perfume & the foam maker?

11. Now imagine you need to make 200 liters (200,000 cm³) of the shampoo. What problem would you need to solve to produce commercial quantities?

12. Think of a name for this “new” shampoo and write a short news release for a hair magazine outlining its cost and benefits. Refer to marketing information or advertising in magazines and/or internet.

If diagrams are decided to be included, they may be drawn in pencil and labelled in ink; they don’t have to be drawn using a computer.

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Using a calculator to calculate the pH from the hydrogen ion concentration

1. The hydrogen ion concentration of a shampoo is 2.4 x 10^-5 mol dm^-3. What is the pH?

pH = - log10[H⁺] pH = - log10[2.4 x 10^-5 ] pH = 4.6.

Press the following buttons in turn: - log 2.4 EXP – 5 = (minus log 2.4 EXP minus 5 equal)

The number4.619788758 will appear. 2.4 is to two significant figures so the pH should be written to two significant figures, so pH = 4.6

2. The pH of a shampoo solution is 4.6 calculate the hydrogen ion concentration?

[H⁺] = 10^-pH [H⁺] = 10^-4.6 [H⁺] = 2.5 x 10^-5 mol dm^-3

Press the following buttons in turn: SHIFT log – 4.6 2.511886432 x 10^-05 will appear.

So the hydrogen ion concentration is 2.5 x 10^-5 mol dm^-3 to two significant figures.

This concludes the requirements for the ICCE Advanced Level Science Project

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Cosmetic ingredients database

Name Chemical type Other information

Acid Compound which dissolves in water to make a solution

with a pH less than 7.

Alkali Compound which dissolves in water to make a solution

with a pH above 7.

Aloe barbadensis (Latin) Skin softener Softens skin, soothes burns and injuries.

Name not used in cosmetics.

Aloe vera (Latin) Skin softener See Aloe barbadensis.

Ammonium laureth sulfate Surfactant See Surfactants.

Compound made from coconut oils. Good at breaking up

oils and soil, so effective in shampoos. Good cleansing agent

and foam maker.

Ammonium lauryl sulfate Surfactant See Surfactants.

Compound made from coconut oils. Mild cleansing properties when used at pH5-6. Non-toxic and not irritating when used in ‘rinse off’ products.

Ammonium xylenesulfonate Solvent Flammable liquid which does not mix with water. No known toxic or irritant effects.

Antiseptic Compound which prevents infection of the skin by

bacteria. Small cuts can be treated with an antiseptic.

Aqua Neutral This is the name used in European cosmetic products for

water. Water is the main ingredient of many cosmetic products so is found first in the ingredients list. Sterile water must be used - this means the water must be boiled to ensure no bacteria or other microorganisms are present.

Arginine Alkali Alkaline amino acid. No value when used in cosmetics.

Behenyl alcohol Emulsifier Non-toxic.

Thickener

Benzophenone Preservative These compounds help prevent the product from reacting with UV light. May cause skin irritation.

Benzyl alcohol Solvent Irritating and corrosive to skin when in concentrated Preservative solution.

Antiseptic

Betaines Compounds used in shampoos to lower the irritation

potential of surfactants. No known toxicity.

continued on next page

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2-bromo-2-nitropane-1,3-diol Preservative Safe when used up to 0.1% concentration.

Binder A substance which absorbs water, swells and helps to hold

other ingredients together.

BHT - Butylated hydroxytoluene Preservative Can cause allergic reactions.

Anti-oxidant

Butylparaben Preservative See Parabens.

Camellia sinesis Oil Oil from the camellia plant. The same plant produces a Perfume green tea, which has lots of positive effects including

reducing blood pressure.

Carbomer Emulsifier White powder. See Emulsifiers. No known toxicity

Thickener or skin irritating properties.

Carboxylic acids Acid Molecules which are based on carbon atoms. The acidity is due to the -COOH (carboxylate) group. The substance dissolves in water making an acidic solution. Used to lower pH of cosmetics.

Castor oil Oil Oil from the seed of the castor oil plant. Soothing to skin.

Cellulose gums Emulsifier See Emulsifiers and Film formers. Compounds from plant Film former cell walls which are resistant to decomposition by bacteria.

Non-toxic.

Cetearyl alcohol Emulsifier Very widely used in hair products. A waxy substance. Non- toxic and not irritating to the skin or scalp.

Cetyl alcohol Skin softener Widely used ingredient extracted from the heads of sperm whales. Added as a solid, waxy substance.

Non-toxic and not irritating.

Chamomila recutita (Latin) Oil Oil from the camomile plant. Soothing to skin.

Chlorhexidine digluconate Antiseptic Cleans bacteria from skin. Can cause dermatitis, which is Alkali severe irritation of the skin, in concentrated solution. Safe

up to 0.2% concentration.

Citric acid Acid Compound obtained from citrus fruit; lemons, oranges,

Sequestering agent grapefruit. Non-toxic - can be drunk in solution of water to Preservative help provide vitamin C.

Citrus limonium (Latin) Oil Lemon oil obtained from the skin of lemons.

Citrus paradisi (Latin) Oil Grapefruit oil obtained from the skin of grapefruit.

Citrus sinensis (Latin) Oil Sweet orange oil obtained from the skin of oranges.

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Cocoglucoside See Glucosides.

Cocoamide DEA /MEA Solvent See DEA.

Emulsifier Surfactant Humectant

Cocoamidopropyl betaine Emulsifier Compound based on coconut oil and beets, eg sugar Surfactant beet. May cause skin irritation.

Thickener

Coconut acid Surfactant Compound found in coconut oil. Used widely in soaps and Skin cleanser shampoos. Very good skin cleanser. May cause skin

irritation.

CI number Colouring pigment There are many colouring pigments which can be used.

Each is registered and given a number.

Colophonium This is a resin obtained from pine trees. Used to give colour

- usually yellow-orange.

Cucumis melo (Latin) Melon extract - usually juice. Used in products for dry hair and to improve skin condition.

Dandruff Human skin flakes produced most often on the scalp. Skin

and allergy specialists disagree about its cause - could be an allergic reaction. Shampoos to treat this use zinc pyrithione and a surfactant.

DEA - Diethanolamine Emulsifier This compound is found in coconut and soybean oils and is Humectant used to make other substances. Has useful properties but Surfactant may cause skin irritation. Can be contaminated with Solvent cancer-causing compounds called nitrosoamines during

manufacture.

DMDM hydantoin Preservative ‘DMDM’ stands for ‘Dimethylol dimethyl’. Can irritate the skin. See Preservatives.

Dimethicone Oil Protects skin forming a barrier to other liquids.

Dipropylene glycol See Glycols.

Disodium dityrylbiphenyl Colouring agent This gives colour ot the product. Its use is banned in the

disulfonate USA.

Disodium EDTA Preservative ‘EDTA’ stands for ‘ethylenediaminetetraacetic acid’.

Disodium laureth sulfosuccinate Surfactant See Surfactants.

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Disodium PEG-4-Cocoamido Surfactant See Surfactants. ‘PEG’ stands for ‘polyethylene glycol’ and

MIPA sulfosuccinate ‘MIPA’ stands for ‘monoisopropanolamine’.

Disodium phosphate Salt See sodium phosphate.

Distearyl ether Skin softener This is made from stearic acid. See Stearic acid and Skin softeners.

Elaesis guineensis (Latin) Oil This is the Latin name for palm kernel oil, which is obtained from the African palm tree.

Emulsifier Substance which is added to help make an emulsion. An

emulsion is the mixture of two liquids which do not usually mix together, such as oil and water. The emulsifier helps to keep the two liquids mixed, stopping layers forming.

Ethyoxydiglycol Solvent Non-toxic and not irritating.

Film former Compounds which give cosmetic products a film-like

appearance - shiny, glossy and with a silky feel.

Formaldehyde Preservative Highly toxic substance causing skin irritation. Use in Disinfectant cosmetics is banned in Japan and Sweden.

Concentration must be less than 0.2%. See Preservatives.

Glucosides Thickening agent Compounds made in reactions between sugars and alcohol.

Glycerin Solvent Also called ‘glycerol’. A compound made during soap

Humectant manufacture. Very widely used. Non-toxic and not Skin softener irritating to skin.

Glyceryl cocoate See Coconut oil and Glycerin.

Glycols Humectants Name is from ‘Glycerin’ and ‘Alcohol’. See Humectants.

May cause skin irritation.

Glycol distearate/stearate See Stearic acid.

Guar hydroxypropyltrimonium Preservative Can be toxic. May irritate the skin when used in

chloride Surfactant concentrated solutions. Concentrations as low as 0.1% can

Antiseptic irritate the eye.

Hammamelis virginiana (Latin) Skin anaesthetic Common name is ‘witch hazel’. Obtained from a plant.

Skin freshener Makes the skin feel ‘tight’ and fresh as it dries up grease and moisture.

Hexylene glycol See Glycols.

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Helianthus annus (Latin) Oil Sunflower seed oil. Contains Vitamin E which is thought to help keep skin looking young. Used in anti-aging products.

No known toxicity.

Humectant A substance used to preserve moisture content.

Humulus lupulus (Latin) Perfume From the hops plant. Hops are also used in brewing beer.

Can cause skin irritation.

Hydroxypropylmethylcellulose See Cellulose gums.

Isopropyl myristate A compound made in a reaction between an acid and an

alcohol. Used to form lather. Causes blackheads and is being removed from cosmetics.

Lactic acid Skin freshener See Carboxylic acids. Corrosive in concentrated solutions.

May sting sensitive skin.

Lanolin Greasy substance from wool which absorbs water and

holds it on to the skin. Can cause skin irritation.

Laureth number 1-23 Surfactant See Surfactants.

Laureth 11 carboxylic acid Acid See Carboxylic acids.

Lauric acid Foam maker Compound which reacts with water to make a foam. The

Acid molecules are made from 10 carbon atoms joined in a line, with hydrogen atoms and oxygen atoms. See also

Carboxylic acids

Lauryl glucoside Surfactant See Surfactants.

Magnesium nitrate Salt See Nitrates.

Magnolia biondii (Latin) Perfume Non-toxic perfume from the magnolia tree.

Maleated soybean oil Preservative Soybean oil from the soya bean plant which has been Oil partially changed to Maleic acid. Maleic acid is a carboxylic

acid (see Carboxylic acids). The change is made to reduce the effects of soybean oil on the skin - these include skin irritation, hair damage and acne-like pimples.

Menthol Skin anaesthetic Gives a ‘cool’ feeling to the skin. Acts as an anaesthetic Skin freshener when in 100% concentration. Non-toxic below 3%.

Methyl lactate Skin freshener See Menthol and Lactic acid. This is a compound made from these two substances.

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Methylchloroisothiazolinone Preservative Usually used with methylisothiazolinone. Both are toxic and

(MCT) and can cause skin irritation. Safe in very low concentrations in

Methylisothiazolinone (MIT) products which rinse off the skin.

Methyldibromo glutaronitrile Preservative Toxic substance which is absorbed through the skin. Safe to use in rinse off products.

Methylparaben Preservative See Parabens.

Mica Solid powder Used to give a glow or colour. Not irritating to skin.

Lubricant

Niacinamide Vitamin B Used to treat skin diseases. No known toxicity or irritating properties.

Nitrates Salt Used to help keep colour compounds (see CI number) the

correct shade.

Olea europea (Latin) Oil This is the Latin name for olive oil, which is obtained from olives. The same oil can be used in cooking. May cause skin irritation.

Parfum This is the general name given to ‘fragrance’. This could

mean one or more compounds added to give the product an attractive smell.

Palm kernel acid Acid This is the oil from the palm nut producted by the palm Oil tree. See Surfactants, Emulsifiers, Opacifiers.

Surfactant Emulsifier Opacifier

Palmitic acid Acid Compound which occurs naturally in many animal fats and

Oil plant oils including cow’s milk, palm nuts and butter. Each molecule has 16 carbon atoms arranged in a long chain, with hydrogen and oxygen atoms. See Carboxylic acid.

Panthenol Skin softener Widely used in hair products. Also known as Vitamin B Vitamin B complex complex factor. Is good for the body so is non-toxic.

Panthenyl ethylether This is made from panthenol (see above).

Parabens Preservatives Most commonly used ingredient other than water. Used in low concentrations so will be found at the ends of ingredients lists. These compounds stop bacteria growing in the product and are not irritating or toxic.

Paraffinium liquidium (Latin) Skin softener Liquid paraffin obtained from wood, coal and petroleum.

Non-toxic and not irritating to skin.

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PEG polyethyleneglycol Binder See Binders, Surfactants, Skin softeners, Solvents, Skin softener Humectants.

Solvent Humectant

PEG 6 caprylic /capric glycerides Skin softener See Skin softeners.

PEG 7 glycerylcocoate Skin cleanser Non-toxic and not irritating to skin.

PEG 40 hydrogenated castor oil See PEG and castor oil.

PEG 150 distearate Skin cleanser Compound made from stearic acid and PEG.

PEG 200 hydroxyglycerylpalmitate Skin cleanser Non-toxic and not irritating to skin.

Petrolatum Skin softener This is the main ingredient in Vaseline and other petroleum jelly products. Used as skin softener, and protects skin from irritation.

Phenoxyethanol Antiseptic Not irritating to skin, but can irritate eyes above 2.2%

concentration.

Polyquaternium 1-14 Antiseptic This is a group of compounds which can be toxic and Surfactant irritating to skin even at low concentrations.

Preservative

Polysorbates 1-85 Emulsifier See Emulsifiers. Non-toxic and not irritating to skin.

PPG 9 laurate PPG stands for ‘Polypropylglycol’. A compound made from

a glycol and lauric acid.

Preservative Compound used to stop bacteria and other

microorganisms like yeasts growing in the product. This is essential to keep the product safe for use. Some

preservatives are added to help keep the product colour, appearance and texture. All cosmetics include

preservatives. Most used today are non-toxic.

Propylene glycol Humectant Also called 1,2-propanediol. This is a widely used cosmetic Solvent ingredient with similar properties to glycerin. It is toxic and Wetting agent its use is being phased out.

PVP/dimethylaminoethyl- Film former See Film former and Thickener.

methylacrylate copolymer Thickener A polymer is a compound made from many smaller molecules joined together. Many copies of small molecules called polyvinylpyrrolidone (PVP) and

dimethylaminoethylmethacrylate are joined in an alternating line to make one long molecule.

Saccharum officinarium (Latin) Sugar cane extract. Also called ‘Black strap molasses’. No use in cosmetics identified.

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Salt The general name for a compound produced in a reaction

between an acid and an alkali. The other product is water.

We often use ‘salt’ to mean ‘sodium chloride’, but this is

not the chemical meaning.

Sequestering agent Preservative preventing changes in colour, texture or

appearance.

Skin anaesthetic Compound which is absorbed into the skin and reduces

the nervous system’s ability to detect sensation. ‘Local’

anaesthetics are used to stop pain for dental operations, wart removal, stitching up cuts and other small skin-based problems.

Skin cleanser Compound which removes grease from the skin.

Skin freshener Compound which creates a ‘tight’ feeling to the skin.

Usually evaporates quickly from the skin, giving a cooling effect.

Skin softener Compound which is absorbed into the skin and replaces

moisture. Helps to remove dry patches. Also called

‘emollients’.

Sodium benzoate Preservative Non-toxic.

Sodium C12-13 pareth sulfate Salt Compound based on PEG.

Skin softener Humectant

Sodium citrate Sequestering agent Non-toxic.

Sodium chloride Salt May cause drying of the skin. May cause skin irritation.

Antiseptic

Sodium cocoyl isethionate Skin cleanser Safe in concentration up to 50% in rinse off products.

Sodium isethionate Alkali This is the name cosmetic producers use for sodium Emulsifier hydroxide. This is toxic and corrosive.

Sodium lauroamphoacetate Surfactant See Surfactants.

Sodium laureth sulfate Water softener Can cause skin and eye irritation in high concentrations.

Surfactant See Surfactants, Water softeners, Skin cleansers.

Skin cleanser

Sodium lauryl sulfate Emulsifier See Surfactants and Emulsifiers. May cause drying of skin Surfactant by removing grease. May be irritating to skin.

Sodium methyl paraben Preservative See Parabens.

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Sodium palm kernelate Salt Compound produced by reacting palm kernel acid with Soap sodium hydroxide. Acts as a soap.

Sodium palmitate Salt Compound produced by reacting sodium hydroxide with

Soap palmitic acid. Acts as a soap.

Sodium peanutate Peanut oil.

Sodium phosphate Salt Compound used to keep pH constant. Non-toxic and not

irritating.

Sodium stearate Salt Compound produced by reacting sodium hydroxide with

Soap stearic acid. Acts as a soap.

Sodium styrene/ Binder May cause skin irritation.

acrylate copolymer Film former

Sodium tallowate Salt Compound formed from tallow, a mixture of animal fats.

Solvent Liquid used to make solutions. Solid substances are added

to the solvent. These dissolve making the solution.

Sorbic acid Preservative Produces velvet-like feel on the skin. Non-toxic, but may Humectant cause irritation to senstive skins.

Stearic acid Acid Naturally occurring compound found in butter, animal fats

and oils. Molecules have 18 carbon atoms arranged in a long chain, bonded to hydrogen and oxygen atoms. Widely used cosmetic ingredient.

Sulfonated oils Emulsifier Remove colour from natural and dyed hair. May cuse Wetting agent drying of the skin.

Surfactants Compounds which lower the surface tension of water. The

name ‘surfactant’ comes from ‘surface active’. There are four types called anionic, cationic, amphoteric and nonionic. The type depends on whether the surfactant molecule breaks up into charged particles called ‘ions’ in water. Found in all substances used for washing.

TEA dodecylbenzenesulfonate Emulsifier See Sulfonated oils.

Tetrasodium EDT Preservative Prevents colour, texture and appearance changes.

See EDTA.

Tetrasodium etidronate Thickener Compound added to make the product less ‘runny’.

Has no other cosmetic purpose.

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Titanium dioxide Pigment White compound used to make an opaque product.

Not irritating to skin.

Tocophenylacetate Antioxidant Prevents oxygen from the air reacting with compounds in the product.

Trideceth - 7 See PEG and Glycols.

Triclocarban Antiseptic Used to kill bacteria in ‘medicated’ products.

Triclosan Antiseptic Used to kill bacteria in ‘medicated’ products.

Trimethylopropane Perfume Used to help make product smell attractive. Occurs tricaprylate/tricaprate naturally in sweat, cow and goat milks, coconut oil and

palm oil. Non-toxic.

Water softener Compound added to remove calcium and magnesium ions

which cause ‘hard’ water and prevent a lather forming with soap.

Wetting agent A compound which dissolves in water and helps to make

water spread across a surface by lowering surface tension.

This means the same as surfactant, but in cosmetics seems to be used to describe different compounds.

Zinc pyrithione /pyridinethione Antidandruff Added to shampoos to treat dandruff (see dandruff). Some substance evidence this can damage nerves.

Zinc sulfate Salt Compound made in the reaction between sulfuric acid and

Skin freshener zinc metal. May cause skin irritation.