资源简介
（友情提示：鼠标拖选单词即时翻译）
Step1. Teacher brings the jar, cardboard and water to the class. Show them to the
students and ask what experiments we can do with them. Let the students show
them and explain the reasons to the students.
Let the students work in groups and discuss the experiments. When one group
is doing the experiments, the others can ask the questions. The teacher can ask
questions, too.
Step2. Now let the students open their books and guess what the experiment is.
Ask the students to say it in English.
Step3. Read the text silently and answers the following questions.
1. What’s a theory?
2. What’s an experiment for?
3. Did Danny read about the experiment? What is it about?
4. Do you think the cardboard can hold the water in the jar? Why?