改进一:利用U型管、带导管的单孔橡皮塞、玻璃纤维或多孔泡沫塑料、弹簧夹等。装置如图1所示:液体反应物从左管口注入到多孔泡沫塑料底部,将U型管向右倾斜,液体与固体接触并反应产生气体。正放则液体与固体脱离,反应将停止。还可在导气管上加一个弹簧夹,反应时打开弹簧夹,向U型 Improvement 1: U-shaped tube, single-hole rubber stopper with conduit, glass fiber or porous foam, spring clip, etc. The device is shown in Figure 1: The liquid reactant is injected from the left nozzle into the bottom of the cellular foam, the U-tube is tilted to the right, and the liquid contacts the solid and reacts to produce gas. When the liquid is released from the solid, the reaction will stop. It is also possible to add a spring clip on the air tube, and open the spring clip to U-shaped when responding.