Teaching Sequence

Work through this resource material in the following sequence:

5 minutes – Part A: Activating Prior Knowledge
15 minutes – Part B: Guardians of the Gums
20 minutes – Part C: Experiment
(20 minutes - Part D: Results - Wait a week to complete this part)
5 minutes – Reflection

Part A: Activating Prior Knowledge

Step 1.

Ask students to run their tongue over their teeth. What does it feel like? If they've just eaten, it might feel sticky, or like there's a layer of something on them. Do students know what this is called?

Step 2.

Ask students what can harm their teeth? Do they know why? Suggestions might include eating too much sugar, not cleaning their teeth, or not drinking enough milk or other dairy products.

Step 3.

Ask students what happens when they don't look after their teeth? Suggestions might include cavities, teeth falling out, and sore gums.

Step 4.

Has anyone ever been to the dentist and gotten a filling? Why? What happened? What did it feel like? Students can volunteer to share their experiences.

Part B: Guardians of the Gums

Step 1.

Read the story Guardians of the Gums.

Step 2.

Discuss with students their thoughts on the book. Prompt their thinking with questions such as:

What's one thing you liked about this story?
What's one thing you learned from this story?
What is one thing you're still wondering about after reading this story?

Step 3.

Show students this image of the anatomy of a tooth and explain the different parts using the prompts below:

Enamel: The crown of a tooth is covered in a substance called enamel, which is very hard and tough. It’s actually the hardest material in the body! Its job is to protect the inner parts of the tooth as they are very sensitive. However, we know that nothing can stand up to the acid caused by the bacteria in plaque eating up the sugar left by food remnants on our teeth. Over time, this acid will wear away the enamel on our teeth.

Dentin: Below the enamel is dentin, which is also a hard substance (but not as hard as enamel). It protects the inside part of your tooth.

Pulp: The inside part of your tooth, the pulp, contains nerve endings and blood vessels. If you've ever had a cavity or eaten something very cold, the part of your tooth that hurts is the pulp, because the nerve endings send messages to the brain. The blood vessels supply the tooth with nutrients to keep it healthy.

Gums: Gums are the soft pink tissues that hold your teeth in place and also help protect the root.

Step 4.

Ask students to run their tongues over their teeth again. Remind students of the bacteria caused by plaque in the Guardians of the Gums story. Explain to students that plaque is like a sticky layer of glue made from bacteria, leftover food particles and saliva that mix in your mouth.

Step 5.

Ask students if they can think of how to get rid of the layer of plaque so that it doesn't build up? Suggestions might include brushing your teeth after meals.

Plaque just builds up again, you cannot stop it. You want to remove it though otherwise it just builds thicker and thicker.

Step 6.

Explain that plaque contains little germs called bacteria. Bacteria love to feed on the sugar that is left on your teeth after you have eaten some delicious food. The bacteria turn the sugar into acid, which dissolves the tooth enamel (the protective part of your tooth).

Step 7.

Ask students what they think will happen if they leave acid on their teeth for too long? Suggestions might include that this causes holes called cavities.

Part C: Experiment

Step 1.

Explain that you are going to conduct an experiment to observe what happens when sugary, acidic drinks are left on our teeth for too long without cleaning them. You will use eggshells as a substitute for tooth enamel. Eggshells and teeth are similar in their chemical structure as both contain calcium, and one of their main functions is to protect.

Step 2.

Carefully place the four eggs into clear glasses.

Step 3.

Carefully fill the first glass with enough water so that it covers half the eggshell, leaving the other half exposed.

Don’t cover the whole egg as if we leave part of it exposed it will be easier for us to observe and compare what changes have been made to the part of the egg that was submerged in the drink.

Step 4.

Do the same with the three remaining eggs, but using fruit juice, soft drink, and a sports drink.

Explain to students that the amount of liquid must be the same; if more of one liquid is used then that could change how the eggshell reacts. We want to test the differences in the types of liquid, not the amounts, and putting different amounts of different liquids would make the test unfair.

Step 5.

Repeat with the second set of eggs, however, before submerging them in the liquid, have students carefully brush them with a layer of toothpaste.

Step 6.

Make labels out of a small piece of paper to mark which glass contains which liquid, being careful to keep track of which eggs are coated with a layer of toothpaste.

Step 7.

Leave the glasses somewhere safe but observable.

Step 8.

Hand the Student Observation Worksheets out to the class. Ask students to make predictions about what impact each liquid will have on the eggshells, and what knowledge is informing these hypotheses. Remind students of the connection between sugar, plaque, decay and tooth enamel.

Part D: Results

Step 1.

After about five days, carefully pour out the liquid from each cup.

Step 2.

Independently, have students observe the eggshells, and use the Student Observation Worksheet to take notes on any changes.

What to expect:

The liquids containing a lot of sugar and acid will eventually cause the eggshell to break down and erode. You will likely be left with the soft egg sac exposed like a water balloon.

This demonstrates the way the pulp inside of a tooth is exposed when the tough outer layer of enamel erodes away, which can happen when we don't take care of our teeth and allow sugar, bacteria and plaque to build up and cause tooth decay over a long time.

The soft drink should have a stronger effect as it contains a strong acid that will immediately begin to break down the shell.

Water should have no effect on the egg as it has a neutral PH level, emphasising why it is the best drink for the health of our teeth.

The fluoride in the toothpaste should have prevented much of the decay and damage to the eggshell, emphasising the importance of brushing our teeth regularly.

Reflection

Review the names and functions of parts of a tooth.

Teacher Reflection

Take this opportunity to reflect on your own teaching:

What did you learn about your teaching practice today?
What worked well?
What didn't work so well?
What would you share?
Where to next?
How are you going to get there?

SugarByHalf - Guardians of the Gums - How Sugar Attacks

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