On November 8, 1895, German physicist Wilhelm Conrad Röntgen made an observation in his laboratory that would transform the way doctors examined the human body. While experimenting with electrical currents passing through a glass tube, he noticed that a fluorescent screen nearby began to glow even though the apparatus was covered to block visible light. His investigation led to the discovery of X-rays, a form of radiation that could pass through materials and reveal structures hidden beneath them.More than a century later, November 8 is marked as World Radiography Day and the International Day of Radiology, commemorating the discovery and recognising the role of medical imaging in healthcare. Röntgen’s work also earned him the first Nobel Prize in Physics in 1901, making his discovery one of the defining moments in the history of science.
How Wilhelm Röntgen discovered X-rays
In 1895, Röntgen was studying cathode rays, which are streams of electrons produced when an electric current passes through a partially evacuated glass tube. During one experiment, he covered the tube with thick black cardboard to prevent visible light from escaping.Despite the covering, he noticed that a fluorescent screen placed some distance away was emitting light whenever the tube was switched on. The observation suggested that something from inside the apparatus was travelling through the cardboard and causing the screen to glow.Röntgen began investigating the unfamiliar radiation. He found that it could pass through several materials, including paper and wood, while objects such as metal affected how much radiation reached the screen. He also discovered that the rays could expose photographic plates.Since he could not establish the nature of the radiation at the time, he called it X-radiation, using the letter X to represent something unknown. The discovery was announced in his paper, On a New Kind of Rays, submitted in December 1895.
The X-ray image of his wife’s hand
One of the most famous early demonstrations of the discovery involved Röntgen’s wife, Bertha. In December 1895, he placed her hand in the path of the rays and used a photographic plate to record the image.When the plate was developed, it showed the bones inside her hand and the outline of her wedding ring. Unlike an ordinary photograph, the image revealed structures beneath the skin, offering a glimpse of what had previously been hidden from doctors without surgery.The image became an important demonstration of the potential of X-rays. In January 1896, Röntgen presented his discovery publicly before the Physical-Medical Society of Würzburg. During the demonstration, he produced an X-ray image of the hand of anatomist Albert von Kölliker, who suggested that the rays be named after their discoverer.
How the discovery changed medicine
The medical significance of X-rays became apparent soon after Röntgen announced his findings. Doctors began using the technology to examine fractures and locate objects inside the body without having to perform exploratory surgery.By 1896, X-rays were already being used in medical diagnosis, and researchers were also investigating their possible therapeutic applications. The technology gave doctors a new way to examine bones and internal structures, changing the approach to diagnosing injuries and certain diseases.Röntgen received the first Nobel Prize in Physics in 1901 in recognition of his discovery. He did not patent the technology, believing that it should be available for the benefit of humanity. He also donated his Nobel Prize money to the University of Würzburg to support scientific research.
Why November 8 is observed as World Radiography Day
November 8 is observed as World Radiography Day and the International Day of Radiology because it marks the anniversary of Röntgen’s discovery in 1895. The occasion highlights the contribution of radiographers, radiologists and other medical imaging professionals to patient care.X-rays remain an important part of modern healthcare, helping doctors examine fractures, chest conditions and other medical problems. Medical imaging has since expanded to include technologies such as computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound.Röntgen’s laboratory observation more than 130 years ago therefore represents more than a milestone in physics. It helped establish a new way of looking inside the human body and laid the foundation for a field that continues to influence medical diagnosis and treatment.
