Objective
By the end of this lesson, you will understand the basic chemistry behind hair and its properties.
Materials and Prep
- Water
- Shampoo
- Baking soda
- Vinegar
- Comb
- Blow dryer (optional)
No specific prior knowledge is required for this lesson.
Activities
- Mixing Water and Shampoo: Fill a small bowl with water and add a few drops of shampoo. Stir the mixture and observe what happens. Discuss how the shampoo molecules interact with water molecules.
- Exploring pH: In another small bowl, mix equal parts water and baking soda. Stir until the baking soda dissolves. Then, slowly add vinegar to the mixture and observe what happens. Discuss the reaction between the baking soda and vinegar and how it affects the pH.
- Testing Hair Strength: Take a strand of hair and gently stretch it. Observe how it behaves and discuss its elasticity. Then, wet the hair and repeat the stretching test. Discuss how water affects the strength and flexibility of hair.
- Blow Drying Experiment (optional): Wet a strand of hair and use a blow dryer to dry it. Observe any changes in the hair's appearance and discuss the role of heat in altering hair structure.
Sixth Grade Talking Points
- "Chemistry is the study of matter and how it interacts with other substances."
- "Hair is made up of a protein called keratin, which contains carbon, hydrogen, oxygen, nitrogen, and sulfur atoms."
- "Shampoo contains special molecules called surfactants that help remove dirt and oil from hair by interacting with water."
- "Baking soda is a base, while vinegar is an acid. When they react, they create carbon dioxide gas, which causes the fizzing."
- "The pH scale measures how acidic or basic a substance is. Neutral substances have a pH of 7, while acids have a pH below 7 and bases have a pH above 7."
- "Hair has a natural pH of around 4.5-5.5, slightly acidic. Shampoo helps maintain this pH balance."
- "Water can weaken hair's protein structure, making it more prone to damage and breakage."
- "Heat from blow dryers can cause the water in wet hair to evaporate faster, leading to changes in its appearance and texture."