一、探究物体的沉浮条件实验器材:普通的钢笔一支,一个盛有水的透明塑料饮料瓶。实验步骤:首先在笔芯中装一些水,把它放入水中,使之垂直漂浮在水面上。反复调节笔芯中的水量(笔芯如果下沉,说明水量过多,排出一点水,如果露出水面太多,说明水量不够,再吸进一点水),直到胶囊的顶端刚好露出水面为止。然后把笔芯放到盛有水的透明塑料饮料瓶中,将瓶盖旋紧。用手挤压瓶子外壁,瓶子变 First, to explore the ups and downs of the object Experimental equipment: an ordinary pen, a water-filled transparent plastic beverage bottles. Experimental steps: First, add some water in the refill, put it into the water, so that it floats vertically on the water. Repeatedly adjust the amount of water in the refill (refill if the sink, indicating excessive water, discharge a little water, if exposed too much water, indicating insufficient water, and then sucked in a little water) until the top of the capsule just to reveal the surface so far. Then place the refill in a clear plastic drink bottle filled with water and tighten the cap. Squeeze the outer wall of the bottle by hand, the bottle becomes