物理学史上最美的十个实验第九名Rutherfords discovery of the nucleus卢瑟福发现原子核 When Ernest Rutherford was experimenting with radioactivity at the University of Manchester in 1911, atoms were generally believed to consist of large mushy blobs of positive electrical charge with electrons embedded inside the plum pudding model. But when he and his assistants fired tiny positively charged projectiles, called alpha particles, at a thin foil of gold, they were surprised that a tiny percentage of them came bouncing back. It was as though bullets had ricocheted off Jell-O.Rutherford calculated that actually atoms were not so mushy after all. Most of the mass must be concentrated in a tiny core, now called the nucleus, with the electrons hovering around it.1911年卢瑟福还在曼彻斯特大学做放射能实验时，原子在人们的印象中就好像是“葡萄干布丁”，大量正电荷聚集的糊状物质，中间包含着电子微粒。但是他和他的助手发现向金箔发射带正电的阿尔法微粒时有少量被弹回，这使他们非常吃惊。卢瑟福计算出原子并不是一团糊状物质，大部分物质集中在一个中心小核上，现在叫做原子核，电子在它周围环绕。