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A baby's first teeth start to come through when the baby is about six months old. They are called milk teeth or baby teeth.

Children have 20 milk teeth. When you are about 6, they start to wobble and fall out one by one, and bigger adult teeth grow in their place. Grown-ups can have 32 teeth.

Teeth have different jobs. Your flat front teeth cut food, your pointy teeth tear it, and your big back teeth crush and grind it.

The outside of a tooth is covered in enamel. It is the hardest stuff in your whole body!

Experiment: The egg in vinegar

1. Look at the eggs. Tap them gently. Is the shell hard? Our eggshell is going to pretend to be the outside of a tooth.
2. Put one egg in a cup and cover it with water.
3. The teacher puts the other egg in a cup and covers it with vinegar. Vinegar is an acid.
4. Look closely at both cups. Which egg gets tiny bubbles on it?
5. Leave the cups until the next day. Then gently touch both shells. Which one has gone soft or thin?

	Bubbles? (yes / no)	Shell the next day: hard or soft?
Egg in water	Which egg will change? Draw a smiley next to your guess.
Egg in vinegar	Which egg will change? Draw a smiley next to your guess.

Questions

1. Draw your mouth. Draw the front teeth that cut and the back teeth that grind.

   🍎

2. How many times a day should you brush your teeth?

3. The egg in vinegar got bubbles. True or false?

   true / false

4. Why is sugar bad for teeth?

Sources for every fact on this sheet: echoesof.science/school/teeth/sources/

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