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  • Writer's pictureLindsey Noel

Agnes Pockels, Patron Saint of Soapy Surface Tension

Agnes Pockels (1862-1935) never went to college. Although deeply interested in science - physics specifically - at a young age, women in her day were not allowed to attend universities. In fact her knowledge as a young woman was absconded from her younger brother - a famous scientist studying at the University of Göttingen and the namesake of the Pockels Effect - in the form of using his access to the school’s extensive scientific library for her own independent study.

Not only was Agnes unable to attend college due to gender norms of the day (you think 2023 is bad, try Germany in 1880), she was also charged with taking care of her parents who were struck with Malaria and a host of complications thereafter. In her care duties, Agnes spent hours washing dishes. Mesmerized by the sheen that occurred on oily water and the way it moved and shifted, Agnes focused her at-home science experiments on trying to understand the properties of water and various impurities.

Using her practical knowledge from doing the dishes and the textbooks and journals her younger brother shared with her from Göttingen, Agnes Pockels devised a slide trough to take quantitative measurements at the age of 20. What is that exactly? It’s a metal and rectangular shaped trough about 70 cm long, 5 cm wide, and 2 cm deep. It has a ruler along the length of the trough which can therefore determine the surface area of each part of the trough. From this initial design, Ms. Pockels continued to further develop her scientific apparatus by incorporating a small scale to determine the weight or force necessary to remove a small flat object (like a button) from the surface of the water in the trough.

Agnes Pockels art from Women in Science Art on Etsy

created by Jennifer Mondfrans

Agnes Pockels refined and utilized her surface tension measuring method and the apparatus which she created to do so over the next decade. It was such a useful and precise form that Pockels’ design is the basis for the Langmuir-Blodgett Trough, a device that is extensively used in colloid and surface science measurement today. Not surprising as Agnes spent over 10 years testing the trough’s effectiveness in her own kitchen laboratory before speaking to any one in the science world about what she found.

Having gathered an extensive amount of knowledge in her research on surface tension, Agnes felt it wrong to keep her findings secret. She initially contacted University of Göttingen, but they expressed no interest in what she had to offer. So our self made scientist decided to try opening correspondence with Lord Rayleigh, a British mathematician and physicist, who she had heard was publishing studies on the effects of small amounts of oils on the surface of water. He found her letter and the discoveries therein so compelling that he immediately sent it over to the journal Nature. This all occurred in 1891.

Once that first article went to print it was as though the gas pedal inside Agnes Pockels got punched and her journey into the physics of various films exploded with activity. Over the next 2 and a half decades, Ms. Pockels would go on to publish 14 more papers on the subject of surface tension, expanding on the work of other historically scientific minds like Benjamin Franklin (come on, we couldn’t miss out on this perfect philadelphia connection to the history of bubble science) and others. She laid the groundwork for those following her into the field of qualifying surface strength like American chemist Irving Langmuir. Upon Langmuir’s win for the Nobel Prize for Chemistry in 1932 in recognition of his work investigating single layer chemicals on solids and liquids, many commented that this achievement in part was built upon original home science experiments by a young 18 year old woman with a button, a thin tray, and no formal scientific training. Although Agnes Pockels did not receive formal training I’d argue that she crafted her own highly effective & tailored scientific study program. Her lack of professorial guidance seems to have allowed her to focus exclusively on areas of study that interested her. As such, she was able to take great strides in scientific discovery at a much younger age than her contemporaries. While Agnes never received a formal degree, she did receive the Laura R. Leonard Prize from the Colloid Society in 1931 and in 1932 was granted an honorary doctorate from the Braunschweig University of Technology. Agnes Pockels was the first woman to receive this award.

Fast forward - since 1993 the Braunschweig University of Technology has awarded the Agnes Pockels Medal each year to people advancing the institution and its scientific endeavors. Focusing primarily on those who have promoted teaching and research, especially women. The Agnes Pockels Medal remains the legacy of one young woman fascinated by the beautiful worlds contained within the surface of bubbles and the many ways in which they can be made

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