Review for his test Wednesday...

We are studying for his circuits exam.

Review of Introduction to Circuits. He will take his test on Wednesday.

After the Easter party, we started to review topics on Intro to Circuits. He will have a test on it soon.

Discuss the main structure of hair being keratin. The structure of keratin as a fibrous, structural protein, insoluble in water and organic solvents. Keratin is also structurally found in nails, skin, and horns of many animals. Hair consists of 3 sections; the medulla or innermost part, the cortex , or middle highly structured part, and the cuticle,or outer layer containing lipids. The difference between the follicle, hair shaft and root bulb was summarized and diagrammed. Texture of hair consisting of curl pattern, volume, and consistency was discussed in detail for all 3. The shape of the follicle and the circumference determining the texture, volume, and consistency. The chemistry of hair lightening, using bleach to oxidize the melanin to colorless without changing the color of the keratin, which remains pale yellow. Hydrogen peroxide in alkaline solution is used, with the decomposition of peroxide to produce oxygen being the chemical reaction. The chemistry of permanent hair coloring, the use of ammonia to open the cuticle and the depositing of the color in the cortex was the final step in hair coloring.

The lesson outline was the same as Thursday's since Sam was absent for Thursday's. The anatomy and physiology of human hair was covered, specifically the major parts of the shaft being the medulla, cortex, and cuticle. The function of each part briefly discussed as to the location of the color pigments. The colors black and brown formed by the eumelanin and the red color formed by the pheomelanin. All other colors are blends of the pigments, dictated by genetics.

The anatomy of hair and the chemistry of hair will be discussed. The use of acidic dyes consisting of small pigment molecules that can slip inside the hair shaft as temporary hair color. The effect of peroxide on the shaft and how it allows shampoo to eventually dislodge the temporary color. The effect of ammonia, if used,will cause the shaft to open and damage natural color. The use of bleach to oxidize melanin and leave a pale yellow color along with peroxide which opens the shaft in alkaline solution to allow the reaction.

Sam was prompted to list what properties a nail polish should posses.After discussion and questioning, the following were listed.It should not be brittle, maintain color, have shine, adhere to the nail,be nontoxic, and easily removed. The following items were introduced; Nitrocellulose to form a film on the nail, acetates to act as solvents and be volatile, adhesive polymers to insure staying on the nail, pigments like chromium oxide for green, iron oxide for reds and ferrocyanids for blues. The use of plasticizers like camphor for flexibility and UV stabilizers such as benzdophenones to resist color change.

Review of this chapter... Homework is to continue the review...
Discussion of the first picture of a black hole recently discovered...

We read and discussed a paper which dealt with the history of lip color and then the modern chemistry of lipstick production. We discussed the variety of waxes, oils, pigments, and emollients used, their basic uses and formulas. We then watched a video which showed in detail the choice of ingredients used as solvents, oils, waxes and pigments. The chemical compatibility of each with not only the other chemicals but also with the containers used.