Why do models change over time?
Well I had an exam for science and I got the question "Suggest a reason why models change over time" wrong. On the sheet there is a diagram of John Dalton's model of an atom and JJ Thomson's model as an example of models and there is a quote that says " The diagrams represent models that were used at different times in the past to descrribe features of atoms" to explain the diagrams.
Models are testable ideas describing natural phenomena. The model of a flat Earth was based on observations from land. Ocean travelers proved you could not fall off the Earth when making a voyage and further proof was found during the Space Age that Earth was an oblate spheroid. These are examples of models changing over time as technology and equipment improve and ideas become modified. Models seek to represent objects, phenomena and physical processes in a logical way. However, they are sometimes used to simulate and visualize more about the phenomena being studied. Many models were worked on before the model for DNA was refined by Watson and Crick. Using indirect evidence from X-Ray diffraction pictures as well as percentages of the various nucleotides present in DNA, they came up with a double helix model that fit all the criteria. Models are sometimes correct for the period of time in which they are devised, but sometimes must be modified when new ideas and data are presented by other scientists. Science and its models of various phenomena are constantly changing!
Models change because science is based on observation and experiment. Model are based on the current knowledge of a certain time and hence are and would be always incomplete. As quest for truth goes on and new discoveries are made, models are updated based on the new acquired knowledge. If the new knowledge disagrees with the previously acquired knowledge and appears to explain the situation better, then the previous theories and models are rejected.
Hence science is always the half-truth leaving room for new research and the quest for knowledge continues. Even the announcement of the so called God Particle this Wednesday is not the end but beginning of a new era of quest for the ultimate reality.
The Dalton Model of atom was the most simplistic rendering of the matter's basic form. The Model was improved by JJ Thompsom by introducing the concept of charge (electron). Further improvement was done by Rutherford followed by Niels Bohr. The research continued and now we have the Higgs boson but it is not the end.