Week 7
  This week, I will write about field of chemistry. Do you know how many field chemistry have? Chemistry has many field. And it is increasing. Modern chemistry was divided from alchemy in the middle age (from week 1). Modern chemistry do not have long history. So the study have rapidly developed. I will introduce various field.

Organic chemistry
 This chemistry research composition and nature of organic compounds which include carbon atom in the structure except CO2 and CO. Organic compounds have both of combination which is C-C combination and C-H combination or either the two combination. Why was this field created? Because carbon have limitless possibility. Now the number of carbon compound is much more than the number of material which do not include carbon. And the materials which compose our body (for example, protein, nucleic acid, sugar, lipid (fat)) have carbon atom.

Inorganic chemistry
 This chemistry research element, simple substance (単体), inorganic compound. In other words, study of material of not carbon compounds. This chemistry have the longest history in field of chemistry. Modern chemistry is based on alchemy (week 1). Since alchemy mainly researched inorganic compound, first of modern chemistry was inorganic chemistry until J. J. Berzelius used ''organic chemistry'' and ''organic compound'' in 18 century.

Technological chemistry
 This chemistry predict a new substance of nature and explain the known fact of experiment by using numerical formulas and technological model. For example, to research boiling point or melting and a chemical reaction point by using physics. (the same thing is written week 5)

Photo chemistry
 This chemistry research substance whose state is irradiated light. In this chemistry, organic and inorganic compounds are used. The light which is used is decided by the wavelength. X-ray and γ-ray, in short wavelength is very short, are studied in radio chemistry.

Nuclear chemistry
 This chemistry research artificial radioactive material. This is field of inorganic chemistry. Artificial radioactive materials are formed in nuclear reaction. Begin of this field, nuclear chemist researched substance like Plutonium (Pu) which are able to be produced huge quantity. But new artificial radioactive materials are formed a few. So recently nuclear chemistry is same as nuclear physics.

Environmental chemistry
 This chemistry research phenomena which cause in natural world. Aquatic chemistry and soil chemistry are one of this field. But Green Sustainable chemistry is not in this field. The objective of this is to understand circulation of material in natural world and to offer a way of environmental research.

Cosmo chemistry
 This chemistry research structure of star. This chemistry research two ways. One way is to use the spectrum. The other way use meteorite or sample which is picked up by a space probe.

Natural product chemistry
 This chemistry research materials which is produced by creature. In general, this chemistry do not research coal and oil. This chemistry was same as organic chemistry until chemist discovered that organic compounds are able to be produced artificially. And the objective changed to supply the huge price material like dye, perfume and medicine.