用注射器可演示初中物理许多实验，简单，易做，效果明显。1证明大气压的存在取一支SOml，注射器，先把活塞推到顶端，将管内空气排出，然后用眼药水瓶上的橡皮帽将注射管口堵住，把注射器倒挂起来，在它的活塞上悬挂钩码、文具盒等重物，活塞不会被拉出。表明大气对活塞底面有 Using a syringe to demonstrate many of the physics of junior high school, it is simple, easy to do, and the effect is obvious. 1 Prove the presence of atmospheric pressure Take a SOml, syringe, first push the piston to the top, discharge the air inside the tube, then use the rubber cap on the eye drops bottle to block the injection nozzle, hang the syringe up, on its piston Hanging hook code, stationery box and other heavy objects, the piston will not be pulled out. Indicates that the atmosphere has on the underside of the piston