The Rise of Experiment

views updated

The Rise of Experiment

Overview

The publication in 1704 of Isaac Newton's (1642-1727) second major treatise, the Opticks, came at a significant moment in the development of experimental science. Enthusiasm for empirical study of nature, and skill in manipulating experiments, had been building throughout the previous century, and Newton's account of his own experimental studies of light and of his experimental methods fell on fertile ground. The eighteenth century saw a blossoming of experimental efforts in the study of the physical world, especially in exciting new fields such as electricity.

Background

Galileo's (1564-1642) telescopic investigations and his experiments with inclined planes and falling objects were some of the most remarkable discoveries in the history of seventeenth century science, but they were far from isolated events. From planets to plankton, natural philosophers were studying the world around them by interacting with it in new and important ways. The older tradition of contemplative science, which relied on logic and speculation about causes, was replaced by a new tradition aimed at confronting the world directly through the senses and experience. New instruments, such as telescopes, microscopes, and air pumps were invented and used to investigate realms never seen or created before. New practices such as repeated testing of configurations of equipment and systematic improvements to experiments and devices led to sharing of ideas, opinions, and "hypotheses" about experimental outcomes and their meaning. Natural philosophers observed animals, plants and other things in nature with new care. They also manipulated nature through tests and experiments to learn yet more about the physical world.

By the start of the eighteenth century, empiricism—the philosophical outlook that interacting with the physical world is the most effective way to learn about it—and experimental practices of many kinds were well established in the scientific societies of Europe. Curricula changed more slowly but gradually new instruments and an emphasis on experiment made their way into the universities as well. Air pumps (instruments that evacuated the air out of a space to allow for experiments with vacuums), telescopes, thermometers, globes, and orreries (moveable models of the Newtonian universe) were common tools in eighteenth-century university classrooms in British and American universities. Learning through demonstration extended beyond the university: artisans, tradesmen, and others could learn about the Newtonian science from specialized itinerant lecturers at special classes designed to bring together Newton's science with the practical problems of the new industries.

These demonstration experiments were often designed to illustrate to audiences not familiar with advanced mathematics the mathematical laws governing motion presented in Newton's major treatise, The Mathematical Principles of Natural Philosophy. But Newton's work extended to other subjects as well. The Opticks is an account of Newton's experiments with light and colors, his experimental techniques, and his open-ended queries about subjects for future investigation. Newton was not able to determine mathematical relationships to explain his observations of optical phenomena, but he expected that careful experimentation would permit such laws to be determined in the future. The importance of pursuing this goal was on his mind when Newton assumed the presidency of London's Royal Society in 1703. One of his first acts there was to re-establish the practice of weekly demonstration experiments that the Society had let lapse. Some of these demonstrations over the next decades involved the long-popular air pump and the effects of vacuum on various creatures and experimental arrangements. But many others drew more explicitly on the material in Newton's Opticks, and included various investigations into the nature of light and of the relationship between light and electricity. Newton was one among several important figures to emphasize the value of careful experimental practice and the replicability of experiments. By insisting on a high level of precision in performance and reporting, the knowledge produced by experiments became more reliable and could more easily be shared among different investigators. Increasing standards of precision became a hallmark of progress in physical science.

Electricity provides one of the most interesting examples of experimental science in the eighteenth century. The phenomenon of electricity was known but not at all understood in 1700. The simplest experiments with static electricity showing the ability of glass, when rubbed, to attract various light objects and to produce a glow were performed for the Royal Society soon after the start of Newton's presidency. Starting from these modest performances, electrical experiments became more dramatic as investigators learned how to store charges in devices such as Leyden jars. Curiosity about electricity was widespread, and anyone with the means to produce a modest experimental setup could try to advance knowledge of the field. A small number of electrical enthusiasts were killed or seriously injured by experiments that involved natural lightning or very large stored charges, but such martyrdom was rare. One of the most important electrical investigators was the multi-talented Benjamin Franklin (1706-1790). Franklin, working with a group of friends, performed a large number of electrical experiments, helped popularize the use of lightning rods on buildings in Philadelphia, and wrote an influential treatise on the nature of electricity.

Electricity did not remain the private entertainment of sober scientific groups like the Royal Society or dedicated individuals like Franklin. The grand sparks, shocks, and artificial lightning produced pleased all kinds of audiences. Traveling demonstrators took electrical shows on the road, and dramatic electrical games in which shocks were passed through a crowd or various tricks were performed became extremely popular in fashionable circles throughout Europe. The public had previously flocked to see displays of curiosities such as automata and unusual animals, but electricity was a new and fascinating kind of interactive entertainment. It gave audiences a tantalizing sense of the power and control an experimenter could wield over even the most mysterious elements of nature. By getting shocked or wearing a crown of sparks, they could share in the experimenter's mastery as well as his curiosity.

Impact

Interest in experiment and empiricism more generally was a vital quality of seventeenth century natural philosophy. Scientific societies and journals were established in several countries to facilitate the performance of experiments and the exchange of ideas about them. As science found a wider audience after 1700, so did the belief that the natural world could be understood by careful observation and manipulation. Interest in the study of nature and the practice of experiment spread from an elite circle of enthusiasts to a broad cross-section of the general population. Attendance at public lectures and demonstrations stimulated curiosity among people not privileged enough to have attended university, including tradesmen and entrepreneurs who applied the ideas demonstrated by clever experimenters to the practical challenges of their working lives. Women were also part of the growing audience for scientific ideas. In France and Italy as well as Britain, women were both consumers and producers of popular eighteenth century treatises about Newtonian science.

Between the time of Newton and the end of the eighteenth century, the scientific discipline that came to be known as physics was born. For natural philosophers prior to Newton's time, the study of the physical world was not restricted to the subjects later associated with physics but was considered to include topics such as anatomy and botany. With the dissemination of Newton's ideas came a separation. The study of mechanics, statics, dynamics, light, and electricity came together under a new umbrella called "physics." This newly rigorous field was not entirely uniform, however. Some areas of physics, such as mechanics, were highly mathematical by the eighteenth century. While their principles could be illustrated by demonstration and experiment, real understanding and innovation required advanced mathematical skills. Other subjects, such as electricity, still had no mathematical laws, and were approached through experiment and qualitative theory. What brought these subjects together as physics, and excluded others, was their accessibility to experimental investigation and a shared optimism that such investigations would lead eventually to mathematical relationships and laws.

The study of the principles and experiments of Newton's physics and their applications to the construction of machines large and small helped transform intellectual, commercial, and daily life in myriad ways. The embrace of Newtonian ideas and the principle of empirical investigation brought about generations of improvements to the tools, machines, and techniques of mechanics and craftsmen, leading to the development of the practice of engineering and the evolution of precision equipment of all kinds. These in turn brought diverse new experiences to daily life, as inventions such as the steam engine transformed transportation, production, and work itself.

By the late nineteenth century, scientists and engineers had come together to create several industries wholly based in science. Experimental knowledge and prowess from chemistry helped bring about the pharmaceutical, dye, and munitions industries. Knowledge and skill gained from experimental investigations in physics were essential to the development of the telegraph, telephone, electrical and optical industries, and to the establishment of precision measurement and standards that facilitated international trade in technology. These advances, which were multiplied many times over in the next century, had deep roots in the enthusiasm for experimental knowledge and practice that flourished in the decades after Newton.

LOREN BUTLER FEFFER