Robert Bunsen: Breakthroughs Bigger Than the Burner

Bunsen and Gasometry

Photograph by James P. Blair, National Geographic

Robert Bunsen lived during an increasingly industrial age. Beginning in the late 1830s the curious scientist turned his attention to the study of gases emitted from blast furnaces used in the production of pig iron, a starting material for steel (pictured, a Bulgarian steel mill).

By breaking down the composition of blast furnace exhausts, Bunsen learned that 50 to 80 percent of the fuel used in a typical furnace of the day was being wasted.

Bunsen "developed a methodology for analyzing gases, not only from blast furnaces but from volcanoes and other sources," Nawa said.

"Before he published a book on gasometric methods in 1857, people really had to come to his laboratory in Heidelberg and learn these methods directly from him."

Published March 31, 2011

Bunsen's Elemental Discoveries

Photograph by Emory Kristof, National Geographic

Using spectral analysis, Robert Bunsen and colleague Gustav Kirchhoff detected tiny traces of what turned out to be new elements.

In 1860 Bunsen discovered cesium—pictured in a nuclear-waste reprocessing pool—by analyzing thousands of liters of mineral water, Nawa said. He also found rubidium in 1861 by analyzing the mineral lepidolite. According to Nawa, Bunsen "named these elements after the color of their lines in the emission spectrum—rubidium for red and cesium" after the Latin word for "light blue."

Farther afield, spectroscopy "opened the way to the stars," Nawa said. "In the 19th century it was an important question just what the stars were made of, and there was no way to get that information—there was no possibility of getting material down to Earth.

"But by the light the stars send out, and analysis by a spectroscope, you can see all the different spectral lines and learn what elements are present in the stars."

Published March 31, 2011

Spectroscope and Other Lab Staples

Photograph from World History Archive, Alamy

The spectroscope (above, an illustration of an 1872 model) is just one of many Bunsen inventions. He also designed the water jet pump, which can accelerate filtration by creating vacuums, as well as ice and vapor calorimeters, which measure heat absorption and loss.

"He had many small inventions for everyday laboratory work, which are still in use today," Nawa explained, adding that "it's often difficult to trace historical experimental setups, because so much of this equipment is sort of recombined over and over again with frequent use."

Bunsen also left a human legacy as a very important teacher, Nawa stressed. Over more than 30 years, more than 3,500 pupils passed through his laboratory and trained in his methods. The impact of his students' subsequent work, she said, is incalculable.

Published March 31, 2011

Bunsen's Battery?

Photograph from Sciencephotos/Alamy

In the early 19th century, power was often provided by "wet" galvanic cells, which were extremely expensive due to their platinum components.

"Bunsen substituted the expensive platinum with cheap coal [to create] a comparatively cheap source of electricity and the most efficient way to produce electricity on a large scale before the dynamo," Nawa explained.

In principle, the so-called Bunsen cell—among the earliest dry cells—was the forerunner of the zinc and coal batteries still in use today.

The dry cell (such as the modern household "C" battery pictured in cross-section) is just one of the legacies left behind by Bunsen long after his death in 1899.

"Even though the burner is the only thing that carries on his name," Nawa said, "most of the methods and techniques that Bunsen developed are so common today that their origins have become almost forgotten."

Published March 31, 2011