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William Crookes

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Sir William Crookes was a prominent English chemist and physicist during the 19th century.

Sir William Crooks in his laboratory. Wellcome M0004618
Sir William Crooks in his laboratory. Wellcome M0004618

He was widely regarded as a superb experimentalist due to his original and industrious approach to science. His work spanned many different areas, including pure science and practical applications. He made foundational contributions to both chemistry and physics through his careful observations. His ability to explore diverse subjects made him a well-known and respected figure in the scientific community.

William Crookes 7 Kensington Park Gardens blue plaque
William Crookes 7 Kensington Park Gardens blue plaque

One of Crookes's most significant achievements was the discovery of the chemical element thallium. In 1861, he used a technique called flame spectroscopy to identify the substance. Spectroscopy is the study of the light spectrum emitted by different materials. Crookes noticed a distinct, bright green emission line in the spectrum of his sample. Because of this color, he named the element thallium after the Greek word "thallos," meaning a green shoot or twig.

Thallium sample
Thallium sample

This discovery was later confirmed by other scientists, such as Claude Auguste Lamy, in 1862. To honor his contributions, the mineral crookesite was named after him in 1866.

Crookesite
Crookesite

Crookes also made major breakthroughs in the study of vacuum tubes and physics. In 1875, he invented the Crookes tube, which was a specialized glass tube with a vacuum inside. While investigating the conduction of electricity in low-pressure gases, he observed certain rays. These rays appeared to be emitted from the negative electrode, known as the cathode. He called these "cathode rays," which we now know are streams of free electrons.

Periodic table in the style of a space lemniscate william crookes slide
Periodic table in the style of a space lemniscate william crookes slide

Crookes believed these rays were a unique fourth state of matter called "radiant matter." While his specific theoretical views were later updated, his work provided the foundation for the modern study of plasma physics.

His experimental skills led to several other important scientific tools and inventions. He developed the Crookes radiometer, which uses vanes to rotate when exposed to radiant energy. Although he did not fully understand the exact cause of this movement at the time, the device was a notable discovery. He also created the spinthariscope, which was one of the first instruments used to study nuclear radioactivity. Additionally, he applied his knowledge of light to create a lens for sunglasses that blocked 100% of ultraviolet light. These inventions show how his interests moved between theoretical physics and practical technology.

Crookes's professional life was marked by constant activity and high academic standing. He was elected a fellow of the Royal Society in 1863. He also played a major role in scientific communication by founding the magazine *Chemical News* in 1859. As the editor, he published important works, including Michael Faraday's lectures on the forces of nature. He spent many years managing various scientific journals, such as the *Quarterly Journal of Science*. His ability to combine research with publishing helped spread scientific knowledge to a wider audience.

His personal life and work habits were equally intense. Born in London in 1832, he was the eldest of eight surviving children. He studied organic chemistry at the Royal College of Chemistry, starting in 1848 at age 16. After marrying Ellen in 1856, he established a large family and a professional home in London. By 1880, he lived in Notting Hill and operated what was called the finest private laboratory in Britain.

William Crookes 7 Kensington Park Gardens blue plaque
William Crookes 7 Kensington Park Gardens blue plaque

His daily routine was demanding; he often worked in his laboratory until after midnight.

Crookes's legacy is visible in many modern scientific fields. His early work with vacuum tubes helped pave the way for the development of cathode-ray display devices. His use of spectroscopy allowed scientists to identify elements in various environments, including the Earth and space. By identifying the properties of cathode rays, he helped transition science into the era of subatomic physics. Even his interest in diverse topics like psychical research showed his desire to understand the unknown. He remains a central figure in the history of how we study the physical world.

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🖼️ Images & Media (7)
File:Galó de l'Orde del Mèrit (UK).svg
Galó de l'Orde del Mèrit (UK).svg
File:William Crookes 7 Kensington Park Gardens blue plaque.jpg
William Crookes 7 Kensington Park Gardens...
File:Thallium sample.jpg
Thallium sample.jpg
File:Crookesite.jpg
Crookesite.jpg
File:Sir William Crooks in his laboratory. Wellcome M0004618.jpg
Sir William Crooks in his laboratory....
File:Periodic table in the style of a space lemniscate william crookes slide.jpeg
Periodic table in the style of a space...
File:William Crookes Katie King.png
William Crookes Katie King.png
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