Here, along with teaching, he got an opportunity to do research work. He studied the effects of electricity when passed through a gas at a low pressure in a Crookes tube. He carried forward the incomplete work of British scientists Michael Faraday and William Crookes. Faraday had studied the effects of electricity when passed through solid, liquid and gas. Crookes had fixed two electrodes to both ends of a gas, discharge tube and then passed a high voltage electric current through it.
Now, Roentgen had better equipment to produce high vacuum in the tube. Besides, he had a good assistant too, who was an expert glass blower. He would heat the glass tubes and produce desired shapes out of them. He prepared a tube with two electrodes and created near vacuum in the tube. He connected both the electrodes to a high voltage supply. He noticed that rays were produced near the negative electrode. Further study of the rays revealed that they could produce a shadow of the object kept in their path. They even forced a paddled plate to rotate that was kept in their way. When they hit glass they produced green coloured flourescence or glow. These rays, called cathode rays, were deflected by electric and magnetic fields.
When Roentgen announced his invention and demonstrated it in the assembly of Wurzburg Medical and physical society in December, 1985, experts present in the assembly immediately realized the importance of X-rays in medicine and other fields. It surprised many that Roentgen’s X-rays could penetrate the human flesh. To celebrate Roentgen’s discovery, a dinner and dance party was organized. Many women stayed away from the party, lest the X-rays showed them without clothes in the party.
Gradually, with the spread of information about X-rays, people realized their utility. The misunderstanding regarding the rays also vanished. For his discovery, the Royal Society honored him by awarding him the Rumsford award in 1896. Roentgen was awarded the Nobel Prize for Physics in 1901, which was introduced in the same year. Today, X-ray has become extremely useful in detecting fracture in bones, Surgery, etc. They are equally useful in the study of the internal structure of metals and other scientific researches. X-rays were discovered by the end of 1895 and soon followed the discovery of radioactivity by Becquerel and many other important discoveries by some of the greatest scientists like the Curie couple, Rutherford, Planck, Einstein, Fermi, etc.
Following his important discovery in 1895, he was appointed professor of physics and Munich University in 1900. He worked there till he turned 75 in 1920. He died at the age of 78 in 1923.