´óÏó´«Ã½

Joseph Priestley (1733–1804)

As well as being a philosopher, political theorist and dissenting clergyman, Joseph Priestley was the first scientist to discover oxygen. In August 1774, Priestley isolated what he called an ‘air’ that appeared to be completely new. It wasn’t until March 1775 that he wrote to several people about this new air, after conducting experiments into it.

Priestley shut mice in a tight-sealed container filled with the new air and found they could survive longer than with normal air. Although he didn't know it at the time, Priestley had discovered oxygen.

Louis Pasteur (1822–1895)

Louis Pasteur's research found that the souring of beer and wine was caused by microorganisms, and that these microbes could be removed by boiling and cooling the liquid immediately – now known as pasteurisation. This process was later extended to milk. By pasteurising it, the potentially harmful pathogens within it are killed off, making it much safer to drink.

As well as discovering microbiology, Pasteur also unearthed the process of vaccination. He proved that some diseases are caused by microorganisms that multiply in the body, and that if these microbes are weakened and retained the body forms a resistance to the disease.

Alfred Nobel (1833–1896)

If the most prestigious awards in the world of academia are presented in your name, it's fair to say you’re among the greatest minds in your field. Aside from exceptional linguistic skills (he mastered four foreign languages), Alfred Nobel was a highly successful chemist credited with the invention of dynamite, which historically proved incredibly useful for blasting tunnels, building railways and constructing roads.

Given the widespread use of dynamite, Nobel accumulated great wealth. In his will, he asked that his fortune be used for presenting annual awards in the fields of chemistry, physics, medicine, literature and peace, with an award for economics later added. Today, Nobel Prizes are the pinnacle of achievement in these fields.

Dmitri Mendeleev (1834–1907)

In 1869, Dmitri Mendeleev published what's generally cited as the first periodic table, Mendeleev's Periodic System, which arranged chemical elements in order of their atomic weight. Once arranged, the ordering of elements shows clear groupings where similar properties are displayed.

Anyone who studies the periodic table will know these groups, with the Noble Gases and the Alkaline Earth Metals just two of the columns in the table containing elements with similar properties. As many of the elements hadn't yet been discovered, Mendeleev's table had several gaps. But the nature of it meant he could accurately predict the properties of missing elements.

Marie Curie (1867–1934)

Marie Curie is one of the most famous names in science. This is arguably in part due to the charity set up in her name, but her achievements in chemistry also merit recognition. In 1903 Curie became the first woman to win a Nobel Prize, for Physics. In 1911, upon winning the Nobel Prize for Chemistry, Curie became the first person to win two Nobel Prizes. She's still the only woman to do this and remains the only person to win two Nobel Prizes in multiple sciences.

To earn this recognition, Curie discovered polonium and radium, with her 1911 Nobel Prize awarded for the isolation of radium and its compounds. She's also known for introducing X-ray technology and radium into medicine.

Alice Ball (1892–1916)

The first successful treatment for leprosy was developed by Alice Ball in the early 20th century. She studied at the University of Washington and the College of Hawaii, and was the first African American and first woman to gain a master’s degree in Chemistry.

Her method to treat Hansen’s disease alleviated symptoms of leprosy, resulting in thousands of patients being discharged from healthcare facilities all over the world. Ball tragically died at the age of 24, and it wasn’t until six years after her death that the work was properly credited in her name.

Dorothy Hodgkin (1910–1994)

Winning the Nobel Prize in Chemistry for her research in protein crystallography, Dorothy Hodgkin is widely considered a pioneer in her area of work. After gaining both undergraduate and PhD degrees from the University of Cambridge, she developed the technique of X-ray crystallography, which determines the 3D structures of molecules.

Hodgkin confirmed the structure of vitamin B12 and decoded the structure of penicillin, findings that are vital for work in the field of structural biology today.

Rosalind Franklin (1920–1958)

During her short lifetime, Rosalind Franklin’s work into the fine structure of coal and graphite, as well as the structure of viruses, was widely appreciated. But her contributions in discovering the helical structure of DNA only really gained her posthumous recognition. The double helix shape is one of the most iconic images in chemistry, and Franklin discovered it through her work on the X-ray diffraction images of DNA.

Unlike many on this list, Franklin doesn't have a Nobel Prize to her name. The Nobel Committee doesn't award prizes posthumously, but it’s widely thought that had she been alive, she would’ve shared the Nobel Prizes won by those she worked with.

Marie Maynard Daly (1921–2003)

American biochemist Marie Maynard Daly is widely considered the first African American woman to gain a PhD in Chemistry. She did it from Colombia University, where she researched compounds and the effect they have on the body and digestion.

Throughout her career, she continued important research around cholesterol, sugars and proteins, as well as crucial studies on the effects on the lungs from smoking cigarettes. She also developed programmes to help minority students gain entry into medical school and graduate science programmes.

Mario Molina (1943–2020)

In the 1970s, when Mario Molina began his research, CFCs (chlorofluorocarbons) were used as refrigerants and chemical propellants. They were believed to be harmless, but they kept accumulating in the atmosphere.

Molina and his colleagues wanted to discover what happened to them. They discovered that upon reaching the upper atmosphere, CFCs are destroyed by the sun's radiation. In turn, this process releases chlorine, which eats away at the Earth's ozone layer. The largest hole in the ozone layer is over Antarctica, and this allows harmful UV rays to penetrate our atmosphere and reach the Earth's surface. Had Molina not discovered this phenomenon, humans may never have made efforts to reduce CFC emissions, and the damage to the ozone layer would've been much worse than it is now.