Activity 1.2 - Exploring the science behind cosmetic creams

It is expected that students:

• Develop further an understanding of the general principles of solubility of nonpolar and polar substances; emulsions and emulsifiers.

• Predict solubility of known and unknown substances in different solvents.

Ressources

• http://www.elmhurst.edu/~chm/vchembook/170solutions.html
• http://www.elmhurst.edu/~chm/vchembook/

As in the following lessons students are invited to make a cosmetic product on their own and moreover, deal with product development (why, to whom, how, the probable price, the scientific explanation of the effect etc.), students will investigate the science behind cosmetic creams.

At the very beginning teacher should recall or, when not learned before, introduce students to the key concepts and principles related to polar and non-polar substances, general solubility rule concerning the polarities of a solute and solvent (“like dissolves like”), and emulsions and emulsifiers. Students may also read through the chapter of general principles of solubility (given at the beginning of this teacher manual.

After that students fill the worksheet on solubility (Table 1).

• What are the general principles in predicting the solubility of a particular solute in a particular solvent?