John Dalton Biography

John Dalton was a british mathematician, meteorologist, physicist, chemist, and naturalist, who is recognized for making the first formulation of the atomic model and the table of relative weights of the chemical elements, which were a contribution to generate the starting point of modern chemistry. he is also known for having made a description of the so-called color blindness, which is a visual defect to the perception of colors, a disease he suffered at a certain time in his life.

Dalton was born on september 6, 1766, in Cumberland, United Kingdom. he grew up in a humble family made up of his father Joseph Dalton, his mother Deborah Greenup and his brothers Jonathan and Mary Dalton. john would assist his father and brother in the fields.

Dalton would start high school would be known for his excellent and fast learning in mathematics. he was that good that at the age of 12 he began to teach classes to children in his school and thus could contribute to the economy of his home.

in 1878, he made a partnership with his older brother Jonathan, participating as a teacher in a Quaker school near Kendal.

in 1793, he would move to Manchester seeking a better university education. in that same year, thanks to the help of his friend and philosopher John Gough, he got the position as professor of mathematics and natural philosophy at the new school of Manchester which was an academy of religious dissenters. nevertheless, the financial capacity of the school would begin to fall and makes Dalton resigned to the position in the year 1800 and he would dedicate to teach private classes. in that same year, Dalton published his first book called “observations and meteorological essays” in which he raised and defended the thesis that air is not a chemical combination, but a physical mixture of gases.

 

THE DALTONISM

in 1794, when Dalton was 26 years old, the young man gave his mother some stockings that were blue for him, which was a surprise for his mother since she did not expect purple stockings because they were not common at that time for women. thanks to this event, Dalton realized that neither him nor his brother were able to distinguish the colors properly, which was the starting point for him to present his first work called “extraordinary facts relating to the vision of colors” in which he explained that difficulties in the perception of color are the cause of problems in the vitreous humor.

although this theory was demerited in principle, Dalton’s profound research on the problem he suffered gave rise to the so-called daltonism, which referred to color blindness. in the same year, Dalton would be appointed as a member of the Manchester philosophical and literary society.

 

laws of partial pressures in gases.

in 1801, he gave several lectures, which he called “experimental essays” which dealt with the formation of gas mixtures, the pressure of water vapor and other vapors at different temperatures in empty and air, evaporation, and thermal expansion of the gases. based on the description of these experiments and the observation of the vapor pressure of six liquids, John Dalton was able to conclude and establish that the variation of vapor pressure in all liquids is equivalent to the sum of the pressures of each component of the vapor pressure.

 

atomic theory and relative weights

John Dalton also purposed the first atomic model, which was proposed between 1803 and 1807. this model clarified why chemical substances had a reaction in fixed stoichiometric proportions and why in the reaction of two substances to form one or several compounds, the proportions of these are integers.

in 1803, Dalton would begin to make experiments related to the reaction of nitric oxide with oxygen and found that there were two different proportions in terms of weight (1: 1.7 and 1: 3.4). this experiment brought up the law of multiple proportions or relative atomic weights in which Dalton argued that in a chemical reaction the relative weights of the elements combine with each other in small whole proportions. thanks to this Dalton became the first scientist to publish a table of atomic weights, in which initially they were hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorus.

based on the previous approach, Dalton proposed 5 postulates for his atomic model:

• The matter is made up of small, indivisible and indestructible particles called atoms.
• The atoms of an element are equal, they have the same weight and equal properties,
• The atoms of an element are different from those of any other element and can be distinguished from each other by their respective relative atomic weights
• The atoms of an element are combined with the atoms of other elements to form chemical compounds, and a given compound always has the same relative number of types of atoms
• Atoms cannot be created or divided into smaller particles, nor are they destroyed in the chemical process. A chemical reaction simply changes the way the atoms cluster.

John Dalton would die on july 27, 1884, in Manchester, due to a heart attack.