National Education Telecommunications Network
DEFINITIONS & BACKGROUNDS

  Background: Biology is the science of life.
Introduced in Germany in 1800
Popularized by French naturalist Jean Baptiste de  Lamarck
Greatest stimulus by English zoologist Thomas Henry Huxley an important educator.  He believed that the conventional segregation of zoology and botany was meaningless and that all living things should be studied in an integrated way.
Scientists now realize that many lower organisms are not plants or animals.
Biology divided into hierarchies: Molecule, the cell, the organism, and population.

Within Biology:
 
Biophysics.
Biochemistry.
Nucleic acids & Protein (the key molecules of all living matter).
Cellular biology.
Organismal biology.
Developmental biology (study of organisms growth & development).
Neurophysiology (brain & nervous system).
Ethology (animal behavior).
Population biology & genetics (study of gene changes in populations & ecology; study of populations in their natural habitats.
Biomedicine (application of biological knowledge to human health).

Generally:
Animal                                       Heredity
Animal behavior                        Life
Botany                                       Medicine
Cell                                            Metabolism
Classification                            Plants
Development                            Reproduction
Ecology                                     Respiration
Evolution                                   Zoology
Genetics
 

Back

 
 
 
 

Chemistry                                     -
  Dictionary Definition:
1 : A science that deals with the composition, structure, and properties of substances and with the transformations that they undergo
2 a : The composition and chemical properties of a substance <the chemistry of iron> b : Chemical processes and phenomena (as of an organism) <blood chemistry>
3 : A strong mutual attraction, attachment, or sympathy <they have a special chemistry>
  Background:
First known chemical processes carried out by the artisans of Mesopotamia, Egypt, & China.  Smiths worked with metals such as gold & copper.  Then, the use of copper, bronze, and iron became common.

Discovered methods of setting dyes on different types of cloth as well as potters prepared glazes, and, later, made glass.

Used in magic and as a result developed astronomical, mathematical, and cosmological ideas.

Greeks first culture to consider these ideas scientifically, about 600 BC.

Theory that all matter was derived from water, which could solidify to earth or evaporate to air, soon was expanded to the idea that four elements made up the world - earth, water, air, and fire.

Atom & Atomic Theory came into being.

Aristotle was the most influential of Greek philosophers who believed that four qualities were found in nature - heat, cold, moisture, and dryness, i.e., fire was hot and dry; water was cold and moist; air was hot and moist; and earth was cold and dry.  Aristotle thought it was therefore possible to turn lead into gold.

Aristotle's theory was accepted by many, especially at Alexandria, Egypt which after 300 BC became the intellectual center of the ancient world.  It was believed that the earth was becoming more perfect thus changing metals to gold, might be possible.  This attempted process became know as "alchemy."  Although no one ever succeeded in making gold, many chemical processes were discovered in the attempts.

About the same time, China was attempting to do the same thing, but, for a different reason.  The Chinese believed that gold was a medicine which would give long life or immortality if was consumed.  Again, much practical chemical knowledge was gained from the incorrect theory.

In the 6th century, a university at Edessa in Mesopotamia was established.  Here, large numbers of Greek philosophical and medical writings into Syriac occurred.  In the 7th & 8th centuries Arab conquerors spread Islamic culture over Asia Minor, North Africa, and Spain.  The Caliphs at Baghdad promoted science and learning.  The Syriac translation of Greek texts were again translated, but this time into Arabic.  Alchemy once again flourished and two reasons became prominent to increase the study of chemicals and chemical apparatus:  Wealth and Health.  Important reagents surfaced as the caustic alkalis metals and ammonium salts were discovered, and distillation apparatus improved.

An intellectual reawakening began in western Europe in the 11th century which was stimulated by cultural exchanges between Arabs and Western scholars in Sicily and Spain.  Schools for translators were established.  The manufacture of glass greatly improved, particularly in Venice.  Important products were discovered such as alcohol and the mineral acids:  Nitric, aqua regia (a mixture of nitric and hydrochloric), sulfuric, and hydrochloric.  New reactions could be accomplished using these powerful reagents.  Chinese discovery of nitrates to make gunpowder promoted effective chemical technology into the 13th century.  Generally, during the 13th and 14th centuries, the influence of Aristotle on all areas of scientific thought began to weaken.

After 1500, printed alchemical and technology works appeared in increasing numbers.  By the 16th century, the result of this increasing knowledge became more apparent.  Also, with the rise of practical works in mining and metallurgy, the assaying of ores for their content of valuable metals employed the use of the laboratory balance, or scale, and the development of quantitative methods or chemical analysis.  Physicians, some of whom were alchemists, needed to know the correct weight and volume of doses they prescribed.  They turned to chemical methods for making medicines.

In the 17th century, Jan Baptista van Helmont, a physician who left his practice to study more about chemistry.  He used the balance in an important experiment to show that a specific quantity of sand could be fused with excess alkali to form water glass, and when this product was treated with acid, it regenerated the original amount of sand.  The foundations of the law of conservation of mass occurred.  He also worked with a number of reactions causing aerial fluid to be liberated.  He called this substance "gas."  A kinetic molecular theory of gasses developed.  Experiments by Robert Boyle, an English physicist and chemist whose studies with elasticity, led to the formation of what became known as "Boyle's Law," a generalization of the inverse relation between pressure and volume of a gas.  Theory and experiment became common in the 17th century, and used the idea of heating or burning as an ingredient.

By the 18th century, chemists noted that certain substances combined more easily with, or had a greater affinity for, a given chemical than did others.  Tables were made showing relative affinities when different chemicals were combined.  The use of these tables made it easier to predict chemical reactions before testing in the lab.  These advances led to discovery of new metals and their compounds and reactions.  Studies increased involving the gases, called "airs."  The British physiologist Stephen Hales developed the pneumatic trough to collect and measure the volume of gases released from solids by heating in a closed system and collecting over water.  The British physicist Henry Cavendish isolated "inflammable air" (hydrogen).  He also discovered that by using mercury instead of water as the confining liquid over which gases were collected, made it possible to collect water-soluble gases.  Many new gases were discovered.

By the 19th century, the precision of analytical chemistry had improved so much, chemists were able to show that simple compounds contained fixed and unvarying amounts of their constituent elements.  More than one compound could be formed between the same elements.  In 1811, the Italian physicist Amedeo Avogadro discovered a difference between molecules and atoms.  However, Avogadro's ideas were overlooked for about 50 years.  In 1860, the Italian chemist Stanislao Cannizzaro reintroduced Avogadro's hypotheses.  Much work was performed on atomic weights of all elements.  Instead of taking the value 1 for hydrogen, as the English scientist John Dalton had done in 1803, the molecular weight of oxygen, 32, was then used universally and, expressed in grams, and was called the gram molecular weight of oxygen, or 1 mole of oxygen.  Chemical calculations were standardized, and fixed formulas written.  Soon, electrochemistry was introduced with the discovery of the voltaic pile, (the battery), in 1800.  New metals such as sodium and potassium were discovered.  Organic chemistry provided the "structure theory," which gave a picture of how atoms were actually put together, was not mathematical, but employed a logic all its own.  New areas came into being:  Thermodynamics, colloid, and photo chemistry.  Physical chemistry became a new term.  Radioactivity was was discovered in the 19th century.  The element radium was discovered, in the separation of the new class of substance known as isotopes.

Another major advance for chemistry came in the 20th century with the foundation of "biochemistry."  This involved the analysis of body fluids.  Methods were then rapidly developed to determine the nature and function of the most complex cell constituents.  The genetic code and explained function of the gene, became the basis of all life.  A new study called "molecular biology," was born.  "Materials Science," which is an interdisciplinary combination of physics, chemistry, and engineering, is guiding the design of advanced materials and devices.  The discovery of high temperature superconductors and ceramic compounds that lose their resistance to the flow of electricity above 77 K (-196 degrees C/-321 degrees F).  New tools have risen such as the scanning tunneling microscope and laser.  Soot produced by graphite electrodes has isolated a new form of carbon, called buckminsterfullerene.

The growth of chemical industries has grown tremendously.  Training of professional chemists is now the order of the day rather than 150 years ago when they were not.  Biologists, physicists, and geologists in the past developed their own techniques and ways of looking at the world, but now it is apparent that each science, in its own way, was the study of matter and its changes.  Chemistry is at the base of each of them.
 

Back