Introduction
Results of the 2009 Program for International Assessment (PISA) released in December 2010 showed that students in the United States came in 17th in science among the 34 member countries of Organization for Economic Co-operation and Development (OECD). 1 There are several factors that could be identified to explain why our students are lagging behind. Maybe our science classes are designed to be too "academic" and far removed from everyday life so students simply lose interest and end up just memorizing the lesson. No conceptual understanding occurs. And because they memorize the lesson, they forget it as soon as the quiz or test is over.
At the same time, science classes that encourage memorization do not help students develop interest and a positive attitude towards science.
One way to elicit more interest in science, particularly chemistry, is by providing students with learning experiences that enable them to see how chemistry is ingrained in their everyday life and not the inert subject they think it is that they only encounter within the walls of a science classroom.
The majority of my chemistry students begin the school year with the notion that the course is just one of those academic and difficult subjects they have to take and pass if they plan to go to a four-year college. Thus, I make it a point to write lesson plans that show how chemistry is relevant to students' everyday life. I have noticed that the lessons that generate the most interest and active participation are those that can be linked to what teenagers value the most personally.
Young people are very particular about their physical appearance, especially their hair. This is probably the reason why then Senator Hilary Clinton began her Class Day address to the 2001 graduating class at Yale College with the following:
''The most important thing I have to say to you today is that hair matters. This is a life lesson my family did not teach me, Wellesley and Yale Law School failed to instill: Your hair will send significant messages to those around you. What hopes and dreams you have for the world, but more, what hopes and dreams you have for your hair. Pay attention to your hair, because everyone else will." 2
Mrs. Clinton might as well have been talking to high school students because just like college students, they, too, pay a LOT of attention to their hair. Many use their hair to establish and project their identity. It is one part of their body that can readily be changed to reflect their mood, feelings or even their personality. They can have it permed, straightened, braided, colored, etc. And on a day, they wake up to realize their hair "decides" to be stubborn and refuses to look the way it should, a "bad hair day" promptly begins and despair sets in!
This is where chemistry can come in handy to teenagers having a "bad hair day." Whether one has straight, curly, black, blonde or grey hair can be explained by chemistry. Chemistry can also explain why hair is easy to manage one day and becomes unruly the following day.
Various hair products and treatments that students use to transform hair texture and appearance from dull to shiny, curly to straight or brown to green are based on basic chemistry concepts.
In other words, whether one will have a good or bad hair day all depends on chemistry!
This unit will be implemented in my college prep chemistry classes composed mostly of sophomores and a sprinkling of juniors and seniors. All of them have completed college prep biology, algebra 1 and geometry. A few of the juniors and seniors may be taking physics concurrently. The majority are in the class because they are considering going to a 4-year college.
The unit will be carried out after state standardized testing in late April or early May. By this time, students have gained a basic understanding of atomic structure, chemical bonds, intermolecular forces, types of chemical reactions including redox, shapes and polarity of molecules, acids and bases and polymers – concepts needed to make sense of the unit.
The unit is divided into three parts. Part 1 focuses on the structure of proteins. Part II deals with the relationship between the physical structure and chemical composition of hair and hair properties, shape and color. Part III covers the chemistry behind perming, straightening and coloring.
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