Summary

In this lab students will observe and analyze how different drinks can stain an egg’s shell. They will then associate the results with how these drinks can stain their teeth.

Grade Level

Elementary School

Objectives

By the end of this lab, students should be able to

• Observe and understand that there is a chemical reaction between some drinks and an eggshell.
• Understand that different drinks can stain their teeth
• Record and analyze results.
• Learn the importance of brushing their teeth to maintain healthy teeth.

Chemistry Topics

This lab supports students’ understanding of

• Chemical reaction
• Chemical change
• Acids

Time:

Teacher Preparation: 10 minutes

Lesson: Day 1: 1 hour and 10 minutes; Day 2: 45 minutes.

Materials

Per Group:

• 12 eggs (not boiled)
• 12 clear cups (big enough to fit the eggs and 6 oz. or ¾ cup of a drink)
• 1.5 cups (12oz) of Milk
• 1.5 cups (12oz) Dark soda
• 1.5 cups (12oz) Red Gatorade
• 1.5 cups (12oz) Coffee
• 1.5 cups (12oz) Grape Juice
• 1.5 cups (12oz) Water
• 1 Toothbrush
• Toothpaste
• Crayons
• Measuring cups (¾ cup)
• 6 spoons
• 12 paper plates
• Napkins

Safety

• Always wear safety goggles when handling chemicals in the lab.
• Students should wash their hands thoroughly before leaving the lab.
• Do not consume lab solutions, even if they’re otherwise edible products.
• Food in the lab should be considered a chemical not for consumption.

Teacher Notes

• This lab activity is designed for use in 1^st grade through 5^th grade classrooms.
• A way to introduce the lab is to talk about dental health and the importance of keeping teeth clean. The lab is a demonstration of why people should take care of their teeth.
• Students should be placed in small groups (suggested: 5-6 students per group) and work together to complete the lab.
• The teacher should observe the groups as they pour and measure the drinks into the clear cups.
• Explain that one egg in each of the drink samples will be left overnight to be observed the next day (6 total eggs/cups).
• Enamel is the visible tissue of the tooth where it covers the anatomical crowning and the nerve. Enamel consists of minerals that protect the tooth. The different amounts of minerals in enamel contribute to the strength as well as the brittleness of the tooth. Enamel is avascular, meaning it has no blood flow and it is not renewable, so keeping teeth clean is vital. Drinking liquids with high acid and sugar contents, such as colas or fruit juices, should be done in moderation because staining and decay can occur. The usual color of enamel is a very light yellow to a grayish white. See NIH experiment for more information.
• Eggshells are similar to tooth enamel. They share the same coloring, ranging from light yellow to white. The eggshell protects the egg from breaking, just as tooth enamel protects the tooth from decaying.
• During the 30 minutes in which the eggs are submerged, the teacher can ask the class what kinds of drinks they consume and how do they think it affects their teeth.
• For higher level or older students, you may want to use pH paper or litmus paper to determine which drinks, if any are acidic, and introduce the concept of pH and acidity as well.
• From this lab, students will be able to see the way drinks stain egg shells which is similar to how they will stain our teeth enamel. There are drinks that stain more than others and after brushing there are some stains that were able to be removed. Also, water and milk are drinks that won’t stain our teeth. It is important that if we do drink sodas, coffee, or juices, that we brush our teeth as soon as possible to keep our enamel healthy.