science.

ernest rutherford:
Appropriately, Ernest's first recorded experiment was a cannon constructed from the brass tube of a hat-peg with a marble for a ball and a dose of gunpowder to ignite the device. it was not the best example of Rutherford's experimental savvy, the resulting explosion failing to deliver the marble to the target twenty metres away, but succeeding in destroying the cannon.

The Rutherfords were a close-knit family, gathering around the piano to sing songs; forging a life with few amenities in the isolated and rugged landscape. Though two of the brothers drowned in a childhood accident and another died as an infant, the life of the Rutherford siblings was filled with the curiosity-satiating distractions of growing up in the New Zealand outdoors. There were the stimuli of farm-life: poaching eggs from bird's nests, orchard raiding, swimming in the Wai-iti river, shooting Kereru pigeons fat from feeding on berries, calculating the level for storage ponds at the flax-mill.

Earning enough to feed the family was a struggle for James Rutherford at times. He ran a farm and flax-mill at Foxhill, and another at Pelorus when the family moved there, in 1883. In 1885 he turned to saw-milling, manufacturing railway sleepers for the Government. However due to an economic downturn his contract was cancelled (while he was recovering from an accident which left him with five broken ribs) and he had to leave the family to look for new opportunities in the North Island. He founded a steam driven flax-mill in Pungarehu, Taranaki, employing twenty people, where he moved the family in 1888.

In the school holidays Ernest busied himself with farm chores, helping out on the farm or at the mill. He had distinguished himself from his earliest days at school, but it took two attempts for him to win an education board scholarship and follow his older brother George to Nelson College. For children of less than wealthy parents a scholarship was one of the few options available with which to obtain further learning. Ernest attended Nelson College as a boarder for three years, and came under the tuition of William Littlejohn, who taught him mathematics and elementary science.

He topped his class in every subject in his final year and, after sitting the exam twice, won one of ten nationwide Junior Scholarships. In his final year he was also head boy, dux, and was a forward in the rugby First XV.

In 1890 he enrolled at Canterbury College, University of New Zealand (now The University of Canterbury). At Canterbury College he continued to play rugby and took part in the student Dialectic Society (a debating club) and the Science Society.



Early Experiments
In 1892 Rutherford completed a Bachelor of Arts degree from Canterbury College and won the only available Senior Scholarship for mathematics. This made it possible for him to return to university for an Honours year, completing a Master of Arts with double First Class Honours in Mathematics and Physics.
At Canterbury he was taught by Professor Alexander Bickerton, whose "genuine enthusiasm for science gave a stimulus to me to start investigations of my own" as Rutherford would credit later. It was in 1893 that his talent for original experimentation and research began to manifest itself: a penchant for creating innovative experiments to solve problems. The findings in his first year's research were based on his invention of a machine that could measure time differences of up to hundred-thousandth of a second. With this device he demonstrated that it was possible for iron to be magnetized by high frequency currents.

In 1894 Ernest completed a Bachelor of Science in Geology and Chemistry and in 1895 was awarded an Exhibition of 1851 Science Research Scholarship (but only after the top-ranked candidate withdrew). He elected to work as a research student at the Cavendish Laboratory, University of Cambridge, under Professor J.J. Thomson. The Professor was studying the conduction of electricity in rarefied gases, which led to his 1897 discovery of the electron. This was the first object to be discovered that was smaller than an atom.

At Nelson College and Canterbury College, fostered by Bickerton, Ernest had been no more than an excellent student. With his move to Cambridge on a scholarship designed to benefit young graduates from the outposts of Empire (Rutherford was amongst the first "foreign" students to be admitted to Cambridge, without going through the undergraduate system) his gifts were to be fully recognised. Family anecdote recalls that Ernest was working on the farm when he received news of the scholarship: "That's the last potato I will ever dig" he remarked.



Cambridge, McGill, Manchester
Once in Cambridge he amazed Thomson with his enthusiasm, tenacity and fresh approach. As Campbell has written, Rutherford went to Cambridge with a reputation as an innovator and inventor, and distinguished himself in several fields, initially by divining the electrical properties of solids and then using wireless waves as a method of signalling:
"Rutherford was encouraged in his work by Sir Robert Ball, who had been scientific adviser to the body maintaining lighthouses on the Irish coastline; he wished to solve the difficult problem of a ship’s inability to detect a lighthouse in fog. Sensing fame and fortune, Rutherford increased the sensitivity of his apparatus until he could detect electromagnetic waves over a distance of several hundred metres. Thomson [...] quickly realised that Rutherford was a researcher of exceptional ability and invited him to join in a study of the electrical conduction of gases. The commercial development of wireless technology was thus left for Guglielmo Marconi."

john dalton :John Dalton was born in a small thatched cottage in the village of Eaglesfield, Cumberland, England. That much is certain. What is less certain is the day and date of his birth as his family never recorded it properly in the family bible (the way it was done in those days). However, much later in life, he was told that it was September 5th, 1766, and that is the way history records it.

His family were Quakers, and had been for a long time. His Grandfather had converted to this religion in about 1695, about the time he got married. Dalton's father inherited an estate of about 60 acres and married a local Quaker girl, Deborah Greenup. John Dalton grew up working in the fields and in the family shop where cloth was made. His sister sold paper, ink and pens, but despite all these sources of income they were relatively poor and the boys did not get much formal education.

However, they did get a basic grounding in reading, writing and arithmetic at the nearest Quaker school, which meant that that they were doing better than most. In Dalton's time only about 1 in 200 people could read!

At the Quaker school, called Pardshow Hall one teacher - the "master" - called John Fletcher took a liking inspired the young Quaker boy to take up solving mathematical problems, a skill he quickly mastered. This brought him to the attention of a number of people, including a rich Quaker, Elihu Robinson, who mentored him in mathematics, science and meteorology.

a school of his own After a failed attempt to start a school in his home town of Eaglesfield, John Dalton eventually went into partnership with his brother and in 1785 took over a different school in Kendal where the brothers offered a range of subjects including languages and 21 mathematics and science courses! Despite the school's popularity (they had 60 pupils at one point) the school did not make money and Dalton had to write answers to "ladies questions" in magazines to make needed extra income.

Another person who inspired, instructed and then mentored John Dalton was the blind son of a wealthy Kendal merchant who was very interested in a range of scientific subjects, including optics. John Gough clearly had a significant influence on John Dalton, as the first two books that Dalton published were dedicated to his friend and mentor.

keeping good records One suggestion that Gough made to Dalton was to keep a daily log of the weather and matters meteorological. So he started writing down what he saw and what he measured about the weather patterns in a book, every day. He kept this journal for his entire life, and probably the very last thing he did on the day he died, was to make his final entry.

To make money he gave public lectures and even offered to sell his extensive, eleven volume botanical collection to a local museum, but it was John Gough who in 1793 pulled a few strings and got him a place as a tutor at Manchester College (called the 'New College' and founded by Presbyterians), where he earned 80 pounds a year. He had wanted to become a physician, but his family persuaded him that his bedside manner would keep him poor all his life, so he chose science instead.

going to Manchester Manchester was probably the second largest town in England at that time, and was rapidly becoming the industrial center of the world. This is where the famous "industrial revolution" started and the town boasted colleges, libraries and lots of other intellectual stimulants. Dalton joined the Manchester Literary and Philosophical Society and immediately published his first book on Meteorological Observations and Essays.

In this book Dalton lays out for the first time his ideas on gasses, and that in a mixture of gasses, each gas exists independently of each other gas and acts accordingly. His famous ideas were starting to form.

However, after six years as a college tutor he went private. He gave up the post at the college and offered to tutor individual students privately at the sum of two shillings a session. This allowed him much more time to conduct his own research.

It was a good move, as he was able to think and perform a series of experiments at this time that led him to the "law" or partial pressures of gasses, which he published in an work entitled Experimental Essays on the Constitution of Mixed Gases; on the Force of Steam or Vapour from water and other liquids in different temperatures, both in a Torricellian vacuum and in air; on Evaporation; and on the Expansion of Gasses by Heat

a mixture of gasses Here he explained to the world that if two gasses were mixed together they behave as if they were totally independent of each other. The first gas does not attract or repel the second gas, it just behaves as if the second gas did not exist. The result of this "independence" was that the total pressure exerted by the mixture of gasses was the sum of the separate pressures exerted by each part in the mixture.

He was also able to show that the environment had a measurable affect on the pressure shown by his gasses, and that there was a mathematical relationship between the pressure of a vapor and its ambient temperature.

Many historians think that Dalton chose to study gasses because of his interest in meteorology, a life long interest in which he collected over 200,000 observations. Even when trying to relax, Dalton could not, however, stop keeping records. One of his few methods of relaxation was to go to a pub called the "Dog and Partridge", just outside town. Every Thursday he would bowl heavy black wooden balls across a perfectly kept green lawn (the English call this game "Bowls") and try to hit a tiny white one. His hits, misses and other scores would be as meticulously recorded as his scientific data.

getting a reaction Not all gasses interact harmlessly, as Dalton discovered. In 1803 he began to react a gas called nitric oxide (N0) with oxygen to produce a third type of gas. Strangely the result could come out in one of two ways depending on the proportions, or ratios, of the reacting gasses. Using one set of conditions it looked like nitrogen was combining with oxygen in the ratio 1 to 1.7, but at other times, in the ratio 1 to 1.3. By August 1803 he had the answer to this puzzle - the "law of multiple proportions" which stated that the weights of elements always combine with one another in ratios that were always whole numbers - thus:


2NO + O ---> N2O3
NO + O ---> NO2

In this way, Dalton was able to start working out a table of atomic weights based on the lightest element, hydrogen, having the arbitrary value of 1.

He expressed his ideas about the make up of gasses this way, "we may form an idea of this by supposing a vessel filled with small spherical leaden bullets among which a quantity of fine sand is poured. The balls are to the sand as the particles of bodies are with respect to the caloric; with this difference only, that the balls are supposed to touch each other, whereas the particles of bodies are not in contact, being retained at a small distance from each other by the caloric."

the right word While forming these mental images of the physical composition of gasses, Dalton struggled to find words and images he could use to express his ideas. He found two solutions. From his reading of ancient texts, particularly those of Hindu origin, he found the term "atom eater" used by the author Kanda to describe discontinuous matter. Also that the philosopher Democritus had once described water as mostly empty space with smooth balls gliding over each other. The "balls" he called atoms. Newton also contributed the idea that "... God in the beginning formed matter in solid, massey, hard, impenetrable, moveable particles ..."

This seemed to be the answer. All matter was made up of hard round particles, which he called 'atoms', and that each type of atom, or element, such as hydrogen, oxygen, nitrogen, etc., differed from the next only by its weight.

The atomic theory had been born.

symbolic representation But his next idea was one of equal genius; how to represent this idea symbolically so that tiny, invisible particles could be 'seen' and their combining properties studied.

The solution, so Dalton thought, was to draw circles, each circle representing one of his tiny atomic spheres. Each element could be distinguished by the contents of the circle, thus:


Using this symbolic representation of invisible atoms, their combining properties could be drawn out, played with, thought about, revised and corrected. It was the perfect way of creating a 'laboratory' where atoms could be moved around at will and placed in a series of relationships that could then be confirmed or denied by actual experiments or data. Today scientists are very comfortable with the idea of model building, and using real or computer models to help them prod and poke around an idea. But in Dalton's day this concept was a major breakthrough.

The union of atoms into higher order structures could also be represented, thus:


So chemical reactions could be studied on paper to see if they conformed to observed fact. A way was open that would take the messy mystery out of the nature of physical matter and make it possible to study its properties and behaviors in a rational and mathematical way.

weighty matters On October 21st, 1803, Dalton stood before the Manchester Literary and Philosophical Society (or which he was now the Secretary) and announced to the world the relative weights of the atoms. This fundamental breakthrough in science did not go un-noticed, and he was immediately invited to repeat his announcements before the Royal Institution of London - before a much larger and much more distinguished audience. The word was out, and Dalton's atomic theory began to receive much publicity and debate.

Some scientists accepted the concepts at once; Thomas Thomson and William Hyde Wollaston. Some were skeptical for as long as 60 years; Charles William Eliot of Harvard University was still not convinced when teaching his classes in 1868. While some were down right hostile; Davy was fanatically opposed and even went as far as to mock the "tall, gaunt, awkward scholar" as Dalton was described by the father of William J. Mayo (who was one of Dalton's pupils).

But as more and more experimental work confirmed the theoretical work, even Davy in later life (about 50 years later) was forced to admit that Dalton was right and that all matter was atomic in nature.

the rewards of science England is a country that does not like to reward its heroes, a trait that borders on the pathological at times and a theme that recurs in almost every field of endeavor, especially science. So, event though he was over 60 years old, he still had to teach arithmetic to private students to make a living. His friends tried to get him a modest pension from the Government, but were told "... it would be attended with great difficulty". It took a lot of begging and pleading by some influential persons before Lord Grey's government finally and reluctantly provided a modest means of support for one of it's more innovative scientists. It was only 150 pounds a year.

j.j thompson: o atoms have parts? J.J. Thomson suggested that they do. He advanced the idea that cathode rays are really streams of very small pieces of atoms. Three experiments led him to this.:

irst, in a variation of an 1895 experiment by Jean Perrin, Thomson built a cathode ray tube ending in a pair of metal cylinders with a slit in them. These cylinders were in turn connected to an electrometer, a device for catching and measuring electrical charge. Perrin had found that cathode rays deposited an electric charge. Thomson wanted to see if, by bending the rays with a magnet, he could separate the charge from the rays. He found that when the rays entered the slit in the cylinders, the electrometer measured a large amount of negative charge. The electrometer did not register much electric charge if the rays were bent so they would not enter the slit. As Thomson saw it, the negative charge and the cathode rays must somehow be stuck together: you cannot separate the charge from the rays.

Thomson's apparatus
in the second
experiment. ll attempts had failed when physicists tried to bend cathode rays with an electric field. Now Thomson thought of a new approach. A charged particle will normally curve as it moves through an electric field, but not if it is surrounded by a conductor (a sheath of copper, for example). Thomson suspected that the traces of gas remaining in the tube were being turned into an electrical conductor by the cathode rays themselves. To test this idea, he took great pains to extract nearly all of the gas from a tube, and found that now the cathode rays did bend in an electric field after all.
"What are these particles?
Are they atoms, or
molecules, or matter in a still
finer state of subdivision?"
homson concluded from these two experiments, "I can see no escape from the conclusion that [cathode rays] are charges of negative electricity carried by particles of matter." But, he continued, "What are these particles? are they atoms, or molecules, or matter in a still finer state of subdivision?"

One of the tubes used
in Thomson's third
experiment. homson's third experiment sought to determine the basic properties of the particles. Although he couldn't measure directly the mass or the electric charge of such a particle, he could measure how much the rays were bent by a magnetic field, and how much energy they carried. From this data he could calculate the ratio of the mass of a particle to its electric charge (m/e). He collected data using a variety of tubes and using different gases.

J.J. Thomson
experimenting, in the
Cavendish Lab. he results were astounding. Just as Emil Wiechert had reported earlier that year, the mass-to-charge ratio for cathode rays turned out to be over one thousand times smaller than that of a charged hydrogen atom. Either the cathode rays carried an enormous charge (as compared with a charged atom), or else they were amazingly light relative to their charge.
he choice between these possibilities was settled by Philipp Lenard. Experimenting on how cathode rays penetrate gases, he showed that if cathode rays were particles they had to have a very small mass--far smaller than the mass of any atom. The proof was far from conclusive. But experiments by others in the next two years yielded an independent measurement of the value of the charge (e) and confirmed this remarkable conclusion.

"We have in the cathode rays matter in a new state." homson boldly announced the hypothesis that "we have in the cathode rays matter in a new state, a state in which the subdivision of matter is carried very much further than in the ordinary gaseous state: a state in which all matter... is of one and the same kind; this matter being the substance from which all the chemical elements are built up."