Ingredients: What’s in the stuff we buy?

A project started by the question, “Why is there salt in my shampoo?”

There are thousands of chemical compounds in the ingredients lists of products we buy every day. Knowing what each one is doing in the product has obvious benefits in comparison-shopping. However, it also provides a sneaky way of teaching simple chemistry to people who had no idea they would find it so interesting. I am always looking for ways to make science more interesting to people who think it is only for people who use masking tape on their eyeglasses.

Here’s part of an example —

Sodium benzoate is used in acidic foods and products to control bacteria, mold, yeasts, and other microbes. It interferes with their ability to make energy.

Because it only converts to benzoic acid in acidic environments, it is not used for its anti-microbial action unless the pH is below about 3.6. In the food industry, it is used in items such as jams, salad dressing, juices, pickles, and carbonated drinks.