Chemistry of Cold Fusion

In our group’s previous post, we talked about nuclear fusion in the past but now its back to the future, with cold fusion, (and specifically the Pons-Fleishmann experiement)!

Cold fusion was a concept thought up by Stanley Pons and Martin Fleishmann in 1989. These electrochemists claimed that they had been able to achieve nuclear fusion at room temperature, and dubbed this miracle cold fusion. Had these claims been true, nuclear fusion would have been significantly more feasible for more widespread use. However, when other scientists attempted to replicate this experiment, they were not able to obtain the same of level success, and cold fusion came to be regarded as a myth. Why were other scientists not able to get the same result, you ask? Well lets look at the experiment in detail.

Stanley Pons (University of Utah) and Martin Fleishmann (University of Southampton) hypothesized that nuclear fusion may occur if electrolysis was carried out with deuterium in palladium metal. Electrolysis is simply the process by which a chemical reaction is instigated using an electrical current. Pons and Fleishmann believed that electrolyzed deuterium would have a very high compression ratio and level of mobility, which would allow it to undergo nuclear fusion, and thus produce exorbitant amounts of energy. Palladium naturally experiences a chemical reaction on its surface which causes it to absorb large amounts of hydrogen into its metal. Fleishmann and Pons believed that if enough deuterium (an isotope of hydrogen) atoms were absorbed at once, they may undergo nuclear fusion. To test this theory, they put a palladium cathode in a calorimeter with heavy water, or deuterium oxide (contains more of the deuterium isotope than regular water). Through electrolysis, the deuterium oxide broke down into its elemental components, and the deuterium was absorbed into the palladium. This electrical current was applied over several weeks, and the heat change was measured. For most of the experiment the temperature remained stable at around 30 degrees celsius, but then the temperature would suddenly rise to 50 degrees celsius for two or more days at a time, although the input energy would not change. Thus, during these phases the calculated output energy was significantly higher than the input energy

It is widely believed that the Pons-Fleishmann experiment was flawed, especially in its sources of experimental error. Based on how the experiment was just outlined, what do you think are the sources of experimental error? Check to see if you guessed correctly when we reveal the answer in our group’s next post!


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