Cecilia Payne-Gaposchkin – Women in STEM Research

Cecilia Payne-Gaposchkin, original name in full Cecilia Helena Payne, (born May 10, 1900, Wendover, Eng.—died Dec. 7, 1979, Cambridge, Mass., U.S.) was a British-American astronomer and astrophysicist who found the explanation for the composition of stars in terms of the relative abundance of hydrogen and helium.


She began her scientific career with a scholarship to Cambridge University, where she took the course in physics and was inspired by a lecture on how solar eclipse relate to Einstein’s Theory of General Relativity, which gave her the passion for learning and science on physics and astronomy.

Unfortunately, Cambridge did not have a lot of opportunities for women and did not offer them advanced degree. So, she moved to Massachusetts and pursued a doctoral degree in astronomy and started a fellowship at Harvard College Observatory after meeting Harlow Shapley, and American scientist and the head of the Harvard College Observatory.


She began her astronomy work by calculating the abundance of chemical elements from stellar spectra and her 1925 thesis, entitled Stellar Atmospheres, was famously described by astronomer Otto Struve as “the most brilliant PhD thesis ever written in astronomy.”


When Cecilia Payne began her study of stellar spectra, scientists believed that the relative abundance of elements in the atmospheres of the Sun and the stars was similar to that in Earth’s crust, briefly mean that the star were built like the Earth; but Cecilia proved them wrong.


Cecilia had a better knowledge of atomic spectra than most astronomers at the time. She knew that the extremely hot sun would cause atoms to ionize. She used the equation of an equilibrium of physicist Meghnad Saha on the ionization of atoms to prove that different ionization states would show up as different absorption lines -light frequency-  on the stellar spectra, figuring out how many electrons the atoms had and the elements to which these ions could belong.


She then discovered that the sun is made mostly of the hydrogen and helium and she found similar results to other stars. Cecilia came into conclusion that, unlike on Earth, hydrogen and helium are the dominant elements of the Sun and stars; confirmed to the fraction elements in Milky Way Galaxy that 74% is hydrogen, 24% is helium and the 2% left are all the remaining elements – which proven that Cecilia’s result was right.


Henry Norris Russell, an American astronomer strongly opposed to this conclusion and told her it was “impossible”, but many other astronomers and the scientific community  has read her paper that was turned into a book, Stellar Atmosphere, and realized that she was totally truely correct.


Cecilia Payne made a long journey to prominence in a scientific community that resent to women. Besides, Cecilia accomplishments, being a women meant she was only recognized as a technical assistant who worked at Harvard with her husband, Sergel Gaposchkin. She faced many challenges and arguments within other female scientist who opposed her thesis.

Eventually, in 1956, Cecilia Payne-Gaposchkin, a pioneering astrophysicist and probably the most eminent woman astronomer of all time, became the first female professor in astronomy and her works has made a lot of people understand and discover something new about the universe for decades since she died in Cambridge, Massachusetts, on December 7, 1979.

Physics – Forces Concept and “Coefficient Of Static Friction” Lab

In physics class for this first term of essential, we learned a lot about the concepts from resources and study deeply through different types of problems. These few months, we have studied about forces, friction, static equilibrium, inclined plane and other concepts that related to forces which is what we’re studying in physics currently. Last week, we had our first experimental class in a long time in which we’re doing lab about the inclined plane. The purpose of this lab is to experimentally determine the coefficient of static friction for multiple materials and to solidify students’ understanding of friction.
So what we do is Build a ramp using the plank of a wood place different materials (paper clip, sandpaper, cloth) upon the plank of wood and determine the minimum angle at which the material will slide. We did three trials of this process, and take the average of the three angles we measure. By using the average minimum angle we find for each material to calculate the coefficient of static friction. And then we compare the results to the other group, which turned out to be quite different.

Here is the data for my group.

After we take a look at the data we made a short report by answering some questions about what was happening while we were doing the lab.

Box position: In the experiment, for each trial, we change the position of the box to see the difference. At last, we take the average of it. Its stay in different position and to take the average of it is just not that accurate.
Sandpaper 3: We make the assumption about Sandpaper 3 that it will have the most coefficient of static friction the object is rougher than other objects.

Real-life Factor
Surface of the box: each time we do the experiment, the surface of the box keeps getting smoother that been scratch by different sandpapers, cloth and wood.