Women in Science: Dorothy Crowfoot Hodgkin's X-Ray Crystallography

Ask Science discusses the accomplishments of English chemist Dorothy Crowfoot Hodgkin. Her research in X-ray lasers led to revolutionary treatments for bacterial infections, Alzheimer's, and diabetes. 

Sabrina Stierwalt, PhD
4-minute read
Episode #137


Hi I’m Dr. Sabrina Stierwalt and I’m Ask Science bringing you Quick and Dirty Tips to help you make sense of science.

This weekend is International Women’s Day, a day for celebrating the contributions of women to our world and for drawing attention to the inequalities that women still face. So in that spirit, let’s brainstorm our favorite female scientists. I’ll give you a moment.


If you named Marie Curie and then got stumped, then you probably read the same history and science textbooks that I did in school. What about Rosalind Franklin, Mary Anning, Rachel Carson, or Grace Hopper? (Fun fact: all of those women were honored with Google Doodles over the last year.)

In the past, the work of female scientists may have been overlooked, but that is starting to change. One woman whose efforts are felt every time we go to the doctor with a bacterial infection or pop a B12 vitamin to promote a healthy brain is English chemist Dorothy Crowfoot Hodgkin..

Using X-rays to Crack Nature's Codes

Dr. Hodgkin spent her scientific career as a chemist solving the structure of specific proteins and other biological molecules like vitamins and drugs by advancing the use of a technique called X-ray crystallography. Even before she was 30 years old, she was known as one of the most skilled X-ray crystallographers of her time. She determined how the different components of molecules fit together to form each molecule’s crystalline structure – a sort of high tech version of taking apart a watch to understand its inner workings.

To understand how X-ray crystallography works, we first have to understand diffraction.

You may have heard about the wave-particle duality of light, or the fact that light has both wave and particle-like properties. One way in which light behaves like a wave is by bending when it travels around edges or through slits, a process called diffraction. All waves do this – sound waves and water waves too.

See also: Super Powered Water


Check out this link for an easy experiment you can do at home to see the diffraction of candle light through a slit made by two pencils.

If we shine light waves on an object, we can observe the resulting diffraction pattern or the shadow left by the bending or spreading of the light as it passes through that object. The technique of X-ray crystallography does just that – a crystalline structure (like a protein) is bombarded by a very narrow beam of X-rays. The crystal then causes those light rays to diffract into many specific directions that depend on the make-up and structure of the crystal.


Please note that archive episodes of this podcast may include references to Ask Science. Rights of Albert Einstein are used with permission of The Hebrew University of Jerusalem. Represented exclusively by Greenlight.

About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.