In 1703 Isaac Newton, recently named president of the Royal Society, wished to revitalize that staid organization of prominent British scientists. To this end, he appointed his lab assistant, Francis Hauksbee, to be the official curator, instrument maker and experimentalist.
Hauksbee’s initial demonstrations were of various air pumps that he had devised, but these less than earth-shaking projects quickly evolved into areas that had profound implications for the world-wide scientific community and advanced the study of electricity so that it became as much an object of interest to contemporary researchers as light and gravity.
The main focus soon became static electricity. Before it could be measured and studied, this previously elusive phenomenon had to be generated and stored so that its properties could be apprehended and quantified. The Van de Graaff generator wasn’t to surface until a later century, but for its time, Francis Hauksbee’s machine generated enough static electricity to demonstrate, if not its exact nature, at least that it was closely related to another pervasive phenomenon – light.
The idea behind Hauksbee’s generator is that a triboelectric (electrostatic) effect arises from sliding hands on a spinning glass. The voltage generated ionizes the gases in the globe, creating a blue plasma glow inside (An example can be seen in a modern-day Hauksbee static generator on YouTube).
Hauksbee’s early generators produced enough light to read by, and with their ionizing voltages they were true forerunners of our mercury vapor lamps. The big difference was that they were powered not by a utility voltage but rather by static electrical energy produced locally by friction of two dissimilar materials.
The underlying physics was relatively simple. A static charge can be produced by rubbing two objects – wool and amber for example.
Normally, matter is electrically neutral. In its atoms, the electrons and protons are equal in number. If an atom acquires excess electrons, it becomes negatively charged. If it loses electrons, it becomes positively charged. When two dissimilar materials are rubbed together, one of them may lose electrons and the other may gain electrons so an electrostatic differential appears between them.
How readily materials gain or lose electrons depends upon their place in the triboelectric series. This is a list of materials ranked in order of propensity for gaining or losing electrons. Materials whose atoms are more likely to give up electrons are at the positive end of the series and materials whose atoms want to gain electrons are at the negative end of the series.
Needless to say, this activity takes place in the outermost, or valence shell containing electrons with the highest energy. Reactions that involve electrons residing in other than the valence shell are nuclear, rather than electrical or chemical. The way to look at it is that the act of rubbing the materials together amounts to injecting energy into the system, and this results in the accumulation of an electrostatic difference of potential.
Some materials near the positive end of the triboelectric series are glass, Nylon and wool. Steel is neutral. Vinyl, silicon and Teflon are at the negative end. Materials that are farther apart in the triboelectric series have greater propensity to develop an electrostatic charges when rubbed together.
Francis Hauksbee and colleagues did not focus on taming this static electrical charge to do useful work. The high voltage was difficult to manage, totally out of balance with the available current. The industrial revolution had to await the innovations of Tesla and Edison. Their generation and distribution systems enabled electric motors that could power textile mills, mines and sawmills. We can only speculate how different the present would appear if these inventions had occurred in the reverse order.
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