Watch Out! Acid Attack
Why do I have to brush my teeth is a common question asked by kids. And of course we explain the reason why over and over again. Next time show your students why they have to brushing is so important. 1.) Show students a hard boiled egg. 2.) Ask them, "Why do you think there is a shell around the egg." 3.) Let the students respond. Make sure they come to the conclusion that the hard shell protects the egg. 4.) Now give them you best smile and say, "See my teeth? Just like the egg my teeth are protected. Enamel protects my teeth the same way the shell protects what is inside the egg." 5.) Pour two cups of vinegar into a large jar. 6.) Have a student place the egg in the jar. 7.) Replace the lid on the jar and place the jar in a safe place for student observation. 8.) Ask the students to predict what they think will happen to the egg. 9.) Write the students response on a large piece of paper that will be hung in your room. 10.) When 2 days have passed, slowly and gently remove the egg from the jar. 11.) Allow each student to look at the egg and compare their predictions with the results. Conclusion: Tell the class that the vinegar caused the shell of the egg to break down and become soft, the same way that tooth enamel is damaged by acid and bacteria in the mouth. Brushing every day is the only way to keep this from happening. Hand out a large tooth for the children to write a sentence and draw a picture to illustrate why teeth brushing is important. See ya, I am off to brush my teeth.
If you like this idea see the unit at http://www.geocities.com/Athens/Thebes/9893/teeth.html