Tooth Decay Science Experiments for Kids

Updated April 14, 2017

Teaching children the importance of preventing tooth decay is a valuable lesson, helping instil good oral hygiene habits. In addition to providing factual information to students or having a dentist or hygienist speak to your class, there are several hands-on experiments that can be completed to teach children about tooth decay.

Invisible Plaque

Plaque is hiding on children's teeth and leading to decay without them even knowing it is there. This activity shows students where plaque is hiding. By mixing several drops of food colouring in a small glass of water and asking students to swish the solution in their mouths for several seconds, all areas of plaque will be exposed. After students have brushed their teeth to remove the now red plaque, allow them to swish the mixture again to see that the plaque has been removed as a result of the brushing.

Cavity Progress

Track decay's progress in a cavity pocket by simulating a cavity with an apple and a nail. Place a large nail 1 inch into the side of a firm apple, put the apple in a bag out of the sun and ask students what they think the apple will look like in three weeks. After three weeks have passed, cut the apple in half through the nail hole and observe the results. The large brown area, spreading out from the nail hole, or cavity, represents how tooth decay spreads in a cavity.

Fighting Decay with Toothpaste

Toothpaste plays a valuable role in preventing plaque build-up and decay. This experiment allows children to see the importance of daily brushing. Place one white egg in a cup full of dark soda. Place another egg in a cup of water. Ask students what they think will happen to the eggs overnight. Allow the eggs to sit in the cups until the next day. In the morning, remove the eggs from their cups and observe the colouring on each egg. Use toothpaste and a brush to brush off the plaque and staining that have built up on the egg left in the soda. This shows the importance of toothpaste.

Fighting Decay with Floss

Floss helps protect hard-to-reach areas, such as those between the teeth, from decay. Teach students the importance of flossing by painting your hand, or the hand of a student, with washable tempera paint. Make sure you get paint between your fingers. Ask students what they think will happen when a toothbrush is used to clean off the hand when the fingers are closed together. Have a child brush the hand with a toothbrush. Discuss how there is still paint between the fingers. Have a student use yarn, acting as floss, to remove most of the paint from between the fingers. Talk about how floss helps prevent decay by reaching places the toothbrush can't reach.

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About the Author

Based in Florida, Mandi Titus has been writing since 2002. Her articles have been published on sites such as Goodkin, Go Green Street and Living the Healthy Way. She holds a Bachelor of Science in psychology from Stetson University.