Question

Was franklin correct when he proposed that electricity was caused by an electric fluid(5 marks)

Answer 1

Dear student,

Eventhough Franklins theory was significant at that time of proposal , it had some drawbacks.

Please go through the detailed explanation.

The theory proposed by Benjamin franklin called the unitary, or one-fluid, theory of electricity. This theory claimed that electricity was really one fluid, which could be present in excess, or absent from a body, thus explaining its electrical charge. Franklin’s theory explained how charges could be dispelled and how they could be passed through a chain of people. The fluid theories of electricity eventually became updated to include the effects of magnetism, and electrons (upon their discovery).

Significance of the theory

• Prior to Franklin’s theory, there were many competing theories on how electricity functioned. Franklin’s theory soon became the most widely accepted at the time. Franklin’s theory is also notable, because it is the first theory that viewed electricity as the accumulation of ‘charge’ from somewhere else, rather than an excitation of the matter already present in an object

• Franklin’s theory also provides the basis for conventional current, the thinking of electricity as being the movement of positive charges. Franklin arbitrarily thought of his electrical fluid as being of a positive charge, and therefore all thought was done in the frame of mind of a positive flow. This permeated the mindset of the scientific community to the point that electricity is still being thought of as the flow of positive charges, despite proof that electricity moving through metals (the most common conductor) is done by the electron or negative particle.

• Franklin was also the first person to suggest that lightning was in fact electricity. Franklin suggested that lightning was just a larger version of the small sparks that appeared between two charged objects. He therefore predicted that lightning could be shaped and directed by using a pointed conductor. This was the basis for his famous kite experiment.

Shortcoming of the theory

• Although the one-fluid theory marked a significant advance in discussions of electricity, it did have some deficiencies. Franklin created the theory to explain discharges, an aspect which had been mostly ignored previously. While it explained this well, it was not able to fully explain electrical attraction and repulsion. It made sense that two objects with too much fluid would push away from each other, and why two objects with largely different amounts of fluid would pull towards each other. However, it didn't make sense that two objects with no fluid would repel each other. Too little fluid should not cause a repulsion

• Another difficulty with this model of electricity is that it ignores the interactions between electricity and magnetism. Although this relationship was not well-studied at the time, it was known that there was some connection between the two phenomena. Franklin’s model makes no reference to these forces, and makes no attempt to explain them.

• Although fluid theory was the predominant viewpoint for a time, it was eventually replaced by more modern theories, specifically one which used observations about attractions between current-carrying wires to describe the magnetic effects between them

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