John Tyndall was born on Aug 2 1820, at Leighlin Bridge, County Carlow. Like Einstein, he only received a basic education, unable to obtain a university education until his 30’s, yet despite this, he became one of the greatest scientists of the 19th century. He made several significant contributions to science, but possibly is best remembered as the first person to be able to explain to his children, ‘Why is the sky blue?’ In 1869, he suggested that the sky is blue is due to the scattering of the suns rays by molecules in the atmosphere. This effect is now called the Tyndall effect and the colour generated is called Tyndall blue. However, behind this apparently simple explanation are the fundamentals of the interaction of electromagnetic radiation in liquids and gases. This is known as the science of nephelometry, of which John Tyndall was the founding father. It is the basis of spectrometers, flourimeters and turbimeters.
Despite his family being able to only afford a hedge-school education for him, Tyndall was an avid student, teaching himself after he left school to work as a surveyor working in both Ireland and England. He was introduced to the study of physics began in 1847 when he met George Edmondson, who was trying to introduce the elements of experimental science into his School in Preston. Tyndall became a teacher and driven to learn more, in 1848 traveled to Marburg University in Germany to study chemistry and physics, gaining his PhD in 1949. In 1851, lack of funds forced him back to Edmonson’s school as a teacher, working on new theories and scientific papers in his spare time. Then on 11 th February 1853 his luck changed, when his lecture to the Royal Institution of Great Britain was so well received that he was elected to the Chair of Natural Philosophy at the RI.
As a lecturer, Tyndall was always seeking to liven up his talks by demonstrations. He invented the light-pipe, the forerunner of fibre-optics, in 1854, for a show-stopping finale for his lecture entitled: ‘ Phenomenon Related to the Motion of Liquids ‘. He used a jet of water that flowed from one container to another. As water poured out through the spout of the first container, Tyndall directed a beam of sunlight at the path of the water. The light, as seen by the audience, followed a zigzag path inside the curved path of the water. This phenomenon of internal reflection is how light is transmitted in fibre-optics today.
His studies on radiation through gases and vapours from 1860 are the foundation of today’s science of meteorology. Also in 1860 he invented the first optoelectronic detector circuit, for measuring the temperature of gases by detecting infrared radiation emissions. For this he is considered to be the founder of optoelectronics, and a father of both infrared analysis and spectroscopy. For the first time he was able to study how molecules can either absorb or emit energy, which formed the basis for his theory of the greenhouse effect, a discussion still much debated today.
In 1871, witnessing a death from smoke inhalation, Tyndall devised a new respirator, which filtered the air through layers of glycerine, charcoal and cotton-wool. Air was exhaled through a separate exhaust valve to avoid moisture getting into the filter system. This system is still used today in modern respirators. From the 1870’s he concentrated his efforts on the emerging field of bacteriology, discovering the existence of germ spores, achieving reproducable systems of sterilization before Pasteur and working with Lister on the culture of Penicillin. Ironically, his exploration of medicine was to cause his death. Always an insomniac, Tyndall experimented with sleep cures and tragically in 1893 Tyndall died from an overdose of chloral accidentally administered by his wife Louisa.