Hair's Your Gift
RHS demo of shampoo (detergent part) molecule, note hydrophilic head and hydrophobic tail;LHS I used this to demo shampoo molecules in my model.
Oil/dirt stuck to a hair (yellow piece of wood) cannot be 'hooked' off by water molecules.
When shampoo is used, the shampoo molecules' tails (hydrophobic) stick into the oil and the water hooks into the molecules' heads (hydrophilic).
The water can now remove the oil/dirt from the hair.
Making shampoo- The ingredients.
Adding the different chemicals.
A quality survey...pH is tested.
Delivery
I made and used models to show the structure of hair and how shampoos and conditioners work. Many students are very interested in the chemistry behind hair care and I found that all the research I did beforehand really paid off as they asked some difficult questions.
At first I got the students to design wax, shampoo and conditioner labels after making each product but I found many becoming bored with the designing and therefore producing substandard labels for the conditioner. For subsequent classes, at the beginning of the unit, I got them to design the range of labels with one logo and name.
This worked out excellently as they made their hair wrap button with the logo in mind ie the whole hair care range matched. Doing it this way also required them to decide on fragrances beforehand – this made it easier for me because we only had to have one fragrance sampling session.
Students really enjoyed making and testing a range of hair wax samples. The drop and rub method is a good opportunity to discuss objective vs subjective product testing – it is worthwhile having some mirrors ready as the resulting hair styles are very entertaining. Most pupils changed their recipes after considering their Questionnaire results.This activity provided an effective introduction into the technological processes that are undertaken when a new hair care product is made and we were able to compare what we had done with the processes outlined in the book, "A New Shampoo" which describes the production of a Banana Hair product.
The shampoo and conditioner making sessions were hectic, messy but really successful. Most students also showed a very good understanding of the functions of all the ingredients. Students had a choice of the type of shampoo and conditioner they wished to make and some types involve heating 2 beakers to 750 C and cooling to specific temperatures before ingredients can be added – and also ingredients have to be measured quite accurately but they really rose to the occasion and loved adding and mixing the chemicals and watching the colour changes and viscosity changes. Despite the rule of not tasting ingredients, some students did and found them extremely bitter.
The testing of the shampoos using hair from our local hairdressers was received with mixed reactions. (see experiment in booklet). Quite a few students disliked touching the hair but they got over it and carried out the experiments. Most students managed working with single hairs very well but some needed help with the mechanics of the testing. The activity ended with a negotiated activity... a competition to determine whose hair could hold the most sinkers. Some students even took the activity further and did a Science Fair project on it.
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Lesson Sequence: Biotechnology – 6 x 1.5 hour sessions |
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| 1./ 2. a) |
Introduction to Hair's your Gift Unit – A3, B6a | Opportunity/need explored; Demonstration of the stimuli as detailed above; Students design logo and choose name for Hair care range; Students make labels for hair care products. |
| 2. b) | Hair Wrap and Button A1, 2a, 2b, 3 |
Students choose towelling and cut it using a given pattern; Hair Wrap overlocked and sewn; Students design and make button; Mechanism of hardening of polymer clay explained. |
| 3/4/5 | A1, A3, A4, B5 | Each of the following take place over 3 lessons |
| a) | Making of Hair Wax/Calmer | Students chew comb honey to observe from where the beeswax comes; Students handle blocks of wax to observe that wax is too hard to apply to hair; The concept and method of adding oil to wax to soften it is introduced; Students experiment to find the amount of oil that must be added to make a wax that melts at hand temperature but solidifies on hair (They do the drop and rub test); Students make and enhance wax (glitter/essential oil), compile a questionnaire and allow public to sample wax and answer questionnaire; Students modify wax (if necessary) and make, bottle and label final product. |
| b) | Structure of hair, how hair grows, how shampoos and conditioners work, the function of the various components of shampoos and conditioners, the importance of pH control | Explanation of the above is via models and a series of electron micrographs; Reference to Jeymar products (industrial link); Students chose the shampoo and conditioner they will make from a variety of recipes and examples (unlike the wax and gel, these quantities are given because the ingredients are expensive); Students make shampoo of choice bottle and label. |
| 6. | Shampoo tests and comparison of how our product development compares to that of The Body Shop and Jeymar products A1, B6a, B6b, C7 |
These tests use 3 commercial shampoos and the shampoo the student made
Students test pH using a pH meter and/or universal indicator paper; |
| 7. | Making of conditioner and completion of hair wrap A1, B6a, B6b, C7 |
Students make conditioner of choice, bottle and label; Students sew button onto hair wrap; Students roll up gift pack; Students do component assessment. |
