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人教版物理八年级下册教科书就浮沉条件知识设计了“盐水浮鸡蛋”实验,但笔者在实际教学中发现,让新鲜鸡蛋悬浮很难成功。在漂浮情况下,加入清水后鸡蛋就会马上沉到烧杯底部;在沉底情况下,加浓盐水或食盐,鸡蛋有时会一瞬间上浮至漂浮,有时则始终上浮不起来。一、教材实验不足1.教材实验设计的意图是,新鲜鸡蛋重力不变,通过加食盐或清水调节液体密度,从而改变浮力来控制鸡蛋的浮沉。但存在的问题是,在沉底情况下,
People’s Education Edition Physics eighth grade textbook textbook on the conditions of the design of the floating “brine floating eggs ” experiment, but the author found in the actual teaching, so difficult to suspend fresh egg suspension. In the case of floating, after adding water, the egg will immediately sink to the bottom of the beaker; in the case of sinking, adding concentrated salt water or salt, the egg sometimes floats to the floating moment, sometimes it will not float up all the time. First, the textbook experiment is not enough 1. Textbook experimental design intent is that fresh eggs, the same gravity, by adding salt or water to adjust the liquid density, thereby changing the buoyancy to control the egg floating. But the problem is that in the case of sinking,