四年级的学生上(磁铁)之前,已经有过对磁铁的一些了解,但在一次上课中,当老师拿出一只涂成了“清一色”的条形磁铁时,学生都不认识。仔细一想,原来学生以往学习中认识的磁铁总是涂上了红、蓝两种色彩,突然见到“清一色”的,自然就不认识了。 There was already some knowledge of the magnet before the fourth grader (magnet), but during a class, the student did not know it when the teacher took out a bar magnet painted “all-you-can”. Think carefully, the original understanding of the students in the past to learn the magnet is always painted red and blue two colors, suddenly see “all-clear”, naturally do not know.