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Teacher: The teacher found a strange phenomenon while playing with magnets yesterday. Please observe carefully and think about why the teacher feels strange.

The teacher said, put a bar magnet flat on a pile of paper clips, then pick it up and present it horizontally to the students. )

Health 1: Because magnets can hold many paper clips.

Health 2: Because some places smoke more and some places smoke less.

Teacher: Can you be more specific?

Health 2: Magnets attract more at both ends and less in the middle.

Health 3: I'm surprised that the closer this magnet is to both sides, the more attractive it is, and the closer it is to the middle, the less attractive it is.

Teacher: Your answer is not only scientific, but also concrete. It's really like a scientist. So students, what do you think of when you see this phenomenon?

Health 4: The magnet has strong attraction at both ends and weak middle part.

Teacher: We call this attraction magnetism.

Health 5: The closer a magnet is to both ends, the stronger its magnetism is, and the closer it is to the middle, the weaker its magnetism is.

Teacher: It would be more scientific to add the word "possible" before this sentence, because this is our guess and has not been verified by experiments. Now can you design an experiment to test this hypothesis?

I remember seeing a post on the "Breeze Forum" of "Education Internet" the other day. In the science class of "separating mixture", there is an experiment: let students think of a way to separate mixed sand from soybeans. One of the students stood up and said that soybeans can be germinated first, and then soybean seedlings can be pulled down, thus separating soybeans from sand. What is the landlord going to do in the face of such an accident? Are you sure? Direct denial? Or let the students express their opinions? Obviously, the student misunderstood the separation of soybeans and sand as no soybeans remained in the sand. He hasn't formed the composition characteristics after separation, so he can't change this basic principle. Perhaps for such a conceptual mistake, our teacher can easily find and let the students turn around, but from the thinking analysis behind this statement, it is not a "simple" mistake, which is representative and typical to some extent. I think it is necessary to discuss such a problem. Through discussion, let students understand that separated objects are immutable and some experiments are irreversible. Before the experiment, they must consider the destructive effect of the experiment on the subjects themselves and learn to think carefully before the experiment.