Final answer:
Experiments with high voltage in cathode-ray tubes conducted by scientists like William Crookes and J. J. Thomson resulted in the discovery of electrons and the revelation that atoms could be split into smaller particles.
Step-by-step explanation:
Studies of elements subjected to high voltage in cathode-ray tubes led to the discovery of electrons. This was a landmark event in physics, where scientists such as William Crookes and later J. J. Thomson observed that when a high voltage is applied to electrodes inside an evacuated glass tube, the rarefied gas within glows and emits cathode rays. These cathode rays are streams of electrons that are freed from the atoms and molecules of the gas, demonstrating that electrons are fundamental components of all atoms.
The application of high voltage across the electrodes generates a potential that accelerates these electrons from the cathode (negative electrode) to the anode (positive electrode). As these energetic electrons interact with the gas atoms, they excite them and cause the emission of electromagnetic radiation, revealing the path of the electrons. The studies of gas discharge tubes not only led to the identification of electrons but also proved that atoms could be divided into smaller parts, fundamentally changing our understanding of matter.