Updated: Jul 21
#48 Science in History
23rd March 1989
On this day in 1989, fusion at room temperature was claimed by Martin Fleischmann and Stan Pons.
Fleischmann showing part of his cold fusion test apparatus (Wikipedia)
Fleischmann and Pons announced that they had created a sustained, controlled nuclear fusion reaction at room temperature, claiming they had generated up to 100 per cent more energy than they put in.
Cold fusion is a proposed type of nuclear reaction in which atomic nuclei are fused at a relatively low temperature and pressure compared to ‘hot’ nuclear fusion reactions. In ‘hot’ nuclear fusion, atomic nuclei are heated to extremely high temperatures and pressures, typically in the range of millions of degrees Celsius, to overcome the repulsive force between positively charged nuclei and force them to come together.
In contrast, cold fusion reactions are believed to occur at or near room temperature, making them a potentially revolutionary source of clean and abundant energy.
In a typical cold fusion experiment, heavy water, which is water that contains a higher-than-normal proportion of deuterium, is electrolyzed using a palladium electrode. Deuterium is an isotope of hydrogen that has one neutron in its nucleus, making it heavier than normal hydrogen. The process of electrolysis involves passing an electric current through the heavy water, causing deuterium ions to accumulate on the surface of the palladium electrode.
Under certain conditions, such as the presence of a catalyst or the application of a strong electric or magnetic field, the deuterium nuclei may be forced close enough together to overcome the repulsive force between them and undergo a fusion reaction. The resulting fusion releases a large amount of energy in the form of heat, which can be used to generate electricity.
Despite their claim being exciting and tantalizing, it was soon discredited by leading scientists because they could not replicate the work of the two electrochemists, and they found no evidence of nuclear processes, particularly the presence of neutrons. Some sceptics wondered why the scientists were alive since, they claimed, they would have been killed by the radiation from a significant nuclear fusion reaction.
Fleischmann and Pons were respected scientists in their field and had a reputation for conducting rigorous experiments. Their initial findings were based on experiments that appeared to show excess heat generation, which they believed was indicative of a nuclear reaction. Some critics suggested that the experiments may have been affected by errors in measuring temperature or other experimental parameters, leading to false results.
To date, cold fusion remains a highly controversial and debated topic in the scientific community with many believing the idea to be science fiction.