Mad Munching
September 2, 2014 3:12 pmTooth decay is one of the most common diseases today. To help understand
the causes and implications of tooth decay, this activity uses vinegar and egg shells in a simulation of teeth decomposition.
You Will Need
One per child of each of the following: paper plate, small container or jar, egg shell, cream cracker, piece of bread, vinegar, graph paper.
Plus real teeth (!) if available.
Instructions
‘You’re Crackers!’
1. Have students eat a cracker and observe it on a paper plate. What happened? Why?
2. Place cracker on paper plate. Add water. What happened? Why?
3. Place another cracker on paper plate. Add vinegar. What happened? Why?
Why Are Teeth like Egg Shells?
Using tape, label a small container (eg baby food jar) with child’s name. Place egg shell in jar. Pour a small amount of vinegar in, enough to cover half of shell.
Put the caps on the jars and label the date on the lid.
Let sit several days. Observe changes every day. Have students draw their egg shell, enlarged onto graph paper. After several days each child can blacken in squares on the graph paper to show holes in egg shell.
What’s Happening?
‘You’re Crackers!’
- When the cracker is munched crumbs will be seen – a physical effect
- The cracker should start to dissolve a little when water is dropped onto it.
- Vinegar should dissolve the cracker even more than water showing that saliva contains a weak acid similar to vinegar – a chemical reaction.
Why Are Teeth like Eggshells?
Explain that the holes are places where the vinegar dissolved the calcium in the eggshell.
Enamel on the outside of teeth is also made of calcium and acids found in food can have a similar effect on real teeth.
Extra options: If possible have children bring in lost teeth of their own to inspect. These can also be animal teeth. Show the crown, neck and root of the tooth. Split a tooth if you can to show enamel, pulp and dentin.
Thanks to and adapted from Reach Out/University of Michigan
