Main Idea

Chemists use chemicals to make the household products that we use every day. All of these chemicals have their roots in nature. Many of them have been modified or combined with other ingredients so that we do not recognize them. By making everyday products from scratch, we can learn about biochemistry and about the importance of our natural world.

Background

Many health-care products such as toothpaste, shampoo, and skin lotion are made by chemical engineers. Toothpaste is made from chemicals such as glycerin, saccharine, flavoring, pyrophosphate and sodium fluoride. Through manufacturing, the previously natural ingredients are altered. Some of them are not very healthy for our bodies or the environment. Knowing how health-care products are made, we can substitute natural ingredients that cause us less harm.

Please note that this toothpaste does not contain fluoride, which many dental care experts state is an important part of dental health.

Learning Objectives

• Understand that chemistry is an important part of our everyday lives.
• Experiment with a natural chemical recipe.
• Gain experience assessing the ingredients on product labels.

Time

1 hour, including 30 minutes for Step 1 (which may be done by the teacher).

Introducing the Concept

Have the students make a class list of household products. Discuss how many of these products are made through chemistry. You may want to have a bottle of dish soap or other household goods available so you can refer to labels. Have the students guess the ingredients in the products. Ask them to imagine how toothpaste might be made.

Materials

• 10 ml dried Irish moss
• 500 ml water
• baking soda
• oil of peppermint
• chlorophyll drops
• oil of licorice, fennel or anise
• food coloring
• small container with lid
• spoon
• burner/element
• small pot
• cheesecloth

Hands-On

Make a tasty natural toothpaste that will clean your teeth and protect them from decay.

1. Mix 10 ml of dried Irish moss with 500 ml of water in a small pot and let it stand for 15 minutes. Then put the pot on a burner and bring it to a boil. Reduce the heat, and let it simmer for 15 minutes, then remove it from the burner and let it cool down a bit.
2. Using the cheesecloth, strain the Irish moss mixture into the small container.
3. Mix your toothpaste, testing different amounts of some or all of the remaining ingredients: baking soda, chlorophyll drops, oil of peppermint, oil of licorice, and food coloring. This testing is what chemists must do to create new health-care products.

Minds-On

• What observations can you make about the Irish moss?
• What might cause the Irish moss to change form when heated?
• What is the purpose of the baking soda? The oil of peppermint? The chlorophyll drops?
• What are some alternative ingredients for making toothpaste? Are the ingredients listed on the commercial package? What might you like to see eliminated from the store-bought toothpaste?

Teaching Tips

• The materials for this activity are available at—or can be ordered through—most health food stores.
• Many toothpaste manufacturers do not list all the ingredients on the packaging. One way to discover the ingredients is to call the toll-free number listed on the package and request more information.
• With a younger group of students, you may want to carry out the first part of the activity yourself, rather than have them using a heat element. Another alternative may be to contact a local high school and see if you can arrange to do the experiment with one of their chemistry classes. This way, your students will have an older person helping them with the activity.

Science All Around Us

Begin the activity with a story to demonstrate how this activity might fit into everyday life. The story may be a little wacky, but that’s OK. It’s a good way to encourage creativity as well as give children a reason for wanting to complete the activity. Your toothpaste story might go something like this:

The planet Earth has just been invaded by the toothpaste-eating Molars from the planet Enamelon. They have come to Earth to steal our toothpaste unless we show them how to make their own. You see, their own planet has become so polluted over the years by the Sugar Monsters that it has developed huge holes on its surface called cavities. Future cavities can only be cured by applying toothpaste on their planet’s surface and cleaning it with a brush. If they do not do this soon, they will have no planet left. Show the Molars how to make toothpaste.

Interconnections

Have the students write the remainder of the toothpaste story. As a part of this story, have them include the procedures involved in making toothpaste and their own observations.

Have the students draw a picture of what the planet Enamelon looks like. What might it look like in five years if they do not get the toothpaste they need?

Have the students design packaging for the toothpaste. Encourage them to list their tasty toothpaste ingredients on the packaging. Compare their product to store-bought toothpaste. Can they find similar ingredients?

Ice Energy

Positively Paper

This activity copied from APASE of Vancouver, Canada, which has regrettably disappeared from the Web.

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