Object 1: Rosalind Franklin’s X-ray diffraction of DNA

May 27, 2021


This picture shows the first defining photo of a DNA strand taken by X-ray diffraction. It enriches this exhibition as it was a crucial element to the discovery of the DNA structure. The photo was taken by Rosalind Franklin in 1952, a researcher at Kings College who was trying to explore the structure of the DNA through a special photographic technique called x-ray crystallography (Carr 2019).

Crick and Watson, two scientists with the same goal of exploring the DNA structure, used evidence of the helix structure (seen in the picture above) from Rosalind Franklin. They also used other theoretical and experimental results from other researchers to identify the accepted molecular DNA structure in February 1953. Neither researchers conducted their own experiments when they first published their results in the nature magazine (Kahn Academy n.d.).They had even got access the photographic evidence on the DNA structure without the consent of Rosalind Franklin.

One way in which the object contributes to this exhibition is that this photo represents a substantial part of the historical development of knowledge of DNA at the time. Crick and Watson used this (Carr 2019) knowledge to conclude on the final molecular DNA structure (Kahn Academy n.d.).

This is interesting from a TOK perspective as the new knowledge about the DNA structure concluded by Crick and Watson was deducted from past knowledge, from which Rosalind Franklin’s photo of the DNA helix was the most important.

Furthermore, the photographic evidence of the DNA structure from Rosalind Franklin built on historical knowledge of x-ray diffraction methodologies. These were first introduced in 1912 by Max von Laue, a German Nobel prize winner in physics (Thomas 2012). Franklin applied this knowledge to the relevant knowledge area of the structure of DNA from 1950 onwards. This shows that even her discovery, most represented by this shown object, was based on experimental principles of past knowledge in physics.

Generally, it can be argued that the natural sciences create new current knowledge by building on past knowledge. The new knowledge adds to the scientific results accumulated throughout its historical development. In this respect one can argue that the knowledge base in science increases over time.

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Object 1: Rosalind Franklin’s X-ray diffraction of DNA