Brush Twice a Day (II)

Brush Twice a Day (II) We boil the egg. When it has cooled, Mom hits the shell with a spoon. The shell doesn't break. It protects the inside of the egg She says, " Your teeth have a shell too. It is called enamel. " Now the fun part. We fill the jar with vinegar. Then we put the egg inside and close the jar with a lid. Now, we wait. What will happen?It is exciting. Two days later, we open the jar. The egg shell has become really soft. It is breaking into small pieces. Wow! What is that about? “ The vinegar is a strong acid, just like many foods we eat, ” Mom says. " The vinegar softens the egg shell so it cannot protect what is inside anymore. "

每天刷牙两次(二) 我们煮鸡蛋。当它冷却后，妈妈用勺子敲打蛋壳。壳不会破。它保护着蛋的内部。 她说:“你的牙齿也有一层壳。它被称为珐琅。“现在是有趣的部分。 我们把瓶子装满醋。然后我们把鸡蛋放进去，盖上盖子。现在,我们等待。 会发生什么?这是令人兴奋的。两天后，我们打开罐子。蛋壳变得很软。它碎成了小块。哇!这是怎么回事? “醋是一种强酸，就像我们吃的许多食物一样，”妈妈说。“醋软化了蛋壳，蛋壳就不能再保护里面的东西了。”

Mom smiles at me and says, " That is why you must brush your teeth. Brushing cleans the acid off from them. If you do not brush, the acid will break the enamel. You will have many cavities and toothaches after. " “ No, I don't want that! ” I reply quickly. My mother is smart. Now I know why I should brush my teeth.

妈妈对我笑着说:“这就是为什么你必须刷牙。刷牙可以清除牙齿上的酸。如果你不刷牙，酸会破坏牙釉质。之后你会有很多蛀牙和牙痛。” “不，我不想那样!”我迅速回答。 我妈妈很聪明。现在我知道我为什么要刷牙了。