Discovery of the electron

The discovery of the electron in 1897 by J.J. Thomson was a breakthrough in understanding matter. Through experiments with cathode rays—streams of charged particles—he observed that these rays could be deflected by electric and magnetic fields, indicating they carried negative charge. This showed that atoms, once thought indivisible, contained smaller units. Thomson concluded these particles, called electrons, were fundamental components of all atoms, fundamentally changing our understanding of atomic structure. His work earned him the Nobel Prize and laid the foundation for modern atomic physics.