All corn does not pop． A seed of corn must have 14% water in it to pop．不是所有的玉米都能爆开。只有当一粒玉米种子里含有14%的水分时才能爆开。
Other kinds of corn have less water and do not pop． 少于14%水分的玉米不能爆开。
When you heat a seed of corn， the water inside makes the corn explode．当你加热一粒玉米种子时，种子里的水分使玉米爆开，
This makes a “pop” noise． That is why we call it popcorn．这时会发出“砰砰”的声音，所以我们把它称为爆米花。
The American Indians popped corn a long time ago．很久以前美洲印第安人就开始爆爆米花。
The Indians knew there were three kinds of corn． There was sweet corn for eating， corn for animals， and corn for popping．他们知道一共有三种玉米，分别是可以食用的甜玉米、给动物吃的玉米和爆爆米花的玉米。
The Indians introduced corn to the first settlers， or Pilgrims， when they came to America in 1620．当第一批定居者，也就是清教徒于1620年来到美洲后，印第安人把玉米介绍给了他们。
One year after they came， the Pilgrims had a Thanksgiving dinner． They invited the Indians． 一年后，新移民举行了第一次感恩节，他们邀请了印第安人，
The Indians brought food with them． One Indian brought popcorn! 印第安人带来了食物，其中有一个印第安人带来了爆米花！
Since that time Americans continued to pop corn at home．从那以后，美国人一直在家里爆爆米花。
In 1945 there was a new machine that changed the history of popcorn． 1945年，一种新的机器改变了爆米花的历史。
This electric machine popped corn outside the home．这种电动机器可以在家庭以外的地方爆爆米花。
Soon movie theatres started to sell popcorn to make more money． Popcorn at the movies became more and more popular．很快电影院里开始出售爆米花赚钱。电影院里的爆米花越来越受欢迎。
Today，Americans still continue the custom of eating popcorn at the movies．现在美国人仍旧保持着在电影院里吃爆米花的传统。
