The
Story of Cold Fusion
By Justin Schiltroth
Curriculum
Fit: Biology 20-30 General Learning expectations: Students will “apply cause and effect reasoning to formulate
relationships for a range of instances in which scientific evidence shapes or
refutes a theory; and explain the limitations of science and technology in
answering all questions and solving all problems, using appropriate and
relevant examples that provides students with a common base of experiences
within which they identify and develop key concepts, processes and skills”.
And, “explain and evaluate for a given instance, and from a variety of given
perspectives, how science and technology are influenced and supported by
society; and assess the ability and responsibility of society . . .”
–Alberta Learning
On March 23, 1989 two chemists at the University of Utah announced to the world’s press that they had discovered cold fusion. Martin Fleischmann and Stanley Pons claimed to have harnessed to power responsible for the sun’s tremendous energy in their laboratory. Obviously, the impact of such a discovery would be enormous. Just imagine the commercial or military application of such a tremendous power source. Fleischmann and Pons were so anxious to make public their findings that they failed to follow the standard procedures for releasing scientific discoveries. The press release came before the results were published in a scientific paper. This was a serious breach of scientific etiquette and would later be used to criticize the two scientist’s credibility.
The experiment that they designed was very straightforward and the apparatus they used was very simplistic. It was composed mainly of a beaker of heavy water (water in which the hydrogen atoms are replaced with deuterium) and two electrodes. One electrode was made of palladium and another was made of platinum. They were both inserted into the beaker of heavy water. A small amount of lithium deuteroxide salt was then added to the beaker as a conductor, and a low voltage current was run across the cell over a period of several hundred hours. The theory was that the heavy hydrogen atoms should fuse together into helium on the palladium electrode and release vast amounts of energy, thus cold fusion. This is the way the sun is powered. Fleischmann and Pons claimed that, over time, these cells produced heat and released nuclear byproducts such as neutrons, the telltale signs of cold fusion.
Because of the simplicity of this experiment scientists all over the world were eager to recreate it. The exact details and conditions of Fleischmann and Pons’ experiments, however, were not yet known, and most early attempts at replication failed. Within a week a photocopied manuscript became available, showing the technical details of the experiment. From there, the race was on to replicate the cold fusion cells. Palladium supplies were diminished as scientists all over the world hurried to recreate Fleischmann and Pons’ experiment. This period of scientific history can be documented by the rise and fall in the price of palladium. At the peak of the cold fusion rush, the price had risen to $170 an ounce. As of today, the price has fallen back below what it was before the rush, $95 an ounce.
For a while it looked as tough cold fusion was real. Researchers all over the United States reported positive results from their replication experiments. Texas University announced that they were detecting excess heat from their cells. Georgia Tech announced that they were seeing neutrons. Other positive results were reported by Hungary and elsewhere in Europe. Japan began to launch a massive program of their own and the university of Utah filed for patents on behalf of Fleischmann and Pons. The world was focused on cold fusion. The State Legislature of Utah voted $5 million towards cold fusion research and congress was approached for a further $25 million.
At the time of Fleischmann and Pons’ research, there were actually two Utah groups trying to develop cold fusion. A scientist by the name of Stephen Jones, at Brigham Young University, had also been working on electrolytic cells for several years in hopes of fusing hydrogen. Jones, unaware of Fleischmann and Pons’ research, had developed a cell not unlike theirs. He too found evidence of neutron production. Jones first heard about Fleischmann and Pons’ research in September 1988 when he was sent their research proposal to referee by the Department of Energy. Rivalry, distrust, and suspicion quickly developed between the two groups. Fleischmann and Pons, afraid that Jones might be stealing their ideas on excess heat from their research proposal, called a press conference, even though they had not yet submitted their findings to a scientific paper. At this point Fleischmann and Pons had not had the opportunity to analyze much of their data and their evidence of neutron production was still sketchy at best, but they went ahead with the release anyway. They wanted to get their findings out before Jones had a chance to. They hoped that this early release would ensure them priority to a copyright.
Cold fusion is a process held to be theoretically impossible by nuclear physicists. Pons and Fleischmann had credibility as electrochemists but not as nuclear physicists. They had little or no expertise in neutron measurement. Their research focused mainly on excess heat production and the measurements of neutron production that they had were taken as an afterthought with very crude instruments.
Shortly after the March press conference, Fleischmann presented the evidence of neutrons (a gamma-ray peak) that he had to a panel of scientists. The peak appeared to be, to the physicists in the audience, at the wrong energy to be neutrons. The peak appeared at 2.5 MeV, where as the expected peak for gamma rays produced by neutrons should have been at 2.2 MeV. The physicists were quick to point this out. Mysteriously, by the time the graph was published by Fleischmann and Pons, the peak was given at the correct value of 2.2 MeV. Whether this discrepancy and sudden change in the value resulted from genuine experimental error, or simply by Fleischmann doctoring his results still remains unclear.
When Fleischmann and Pons’ results were finally published, a nuclear physicist by the name of Richard Petrasso, of the MIT Plasma Fusion Center, noticed that the shape of the gamma ray looked wrong. He also claimed that it was impossible to detect such a small peak with the crude equipment that they were using. Soon after Petrasso’s discovery, most, if not all of the researchers around the world began to claim negative results from their electrolytic cell experiments. They claimed that their earlier results of neutron production could be explained away by improper calibration or background radiation from elsewhere in their laboratory.
After this point Fleischmann and Pons attempted to draw the attention back to the excess heat measurements of their experiments, and away from their flawed radiation data. But the weakness of the neutron evidence was taken to demonstrate their incompetence as experimenters. They had lost all of their credibility in the scientific community. Despite their widely recognized expertise in electrochemistry, little attention was paid to their calorimitry evidence. The excess heat was deemed to be due to a chemical reaction within the cell, not fusion. Fleischmann and Pons were declared incompetent experimenters, and their evidence for cold fusion no more than an error of measurement. And so ended the race for cold fusion along with the scientific careers of Fleischmann and Pons.
1. You are a scientist that is skeptical about Fleischmann and Pons’ results of excess heat production. You suspect that the heat is simply due to a chemical reaction within the cell and not cold fusion. Design an experiment to determine if this hypothesis is correct. Remember to use a control.
2. Were Fleischmann and Pons justified in breaching scientific etiquette by calling the press conference before submitting their results to a scientific paper? Explain.
3. Scientists that were replicating Fleischmann and Pons’ experiment were, at first, reporting positive results. However, after a well-known nuclear physicist challenged the evidence for neutron production, the same scientists began reporting negative results. How can you explain this sudden drastic change in results by so many scientists?
4. If cold fusion were as easy to achieve as Fleischmann and Pons proposed, what would the implications on our society be if we could harness such a vast power supply so easily? List at least 4 pros and 4 cons that this new technology would bring.
Collins, H., and Pinch T. (1994). The Golem: What You Should Know About Science. 2nd Ed. Cambridge University Press, New York.
National Fusion Program. (1991). Fusion: Energy for the future. ACEL Research. Chalk River, Ontario.