Different metal containing compounds emit colored light when fireworks burn. This colored light is a combination of series of colors called spectral pattern.(谱带) Each element emits its own characteristic spectral pattern, which can be used to identify the element. This allowed the scientists in 1900s to develop models of the atom's internal structure

3.1 Chemistry developed out of interest in materials The ability to control fire allowed ancient people to prepare copper(7000 years ago) and iron (3200 years ago) for tools and weapons

Acid-base reaction: Transfer of proton Oxidation and reduction: transfer of electron

10.1 Acids donate protons, bases accept them Sulfuric acid is the number one manufactured chemical 85 billion pounds (40,000,000tons) annually in US. Acid has “sour taste

Chapter 1 Chemistry is a Science of Change water molecule is consisted of one oxygen(氧) atom and two hydrogen(氢) atoms A cup of water contains about 1024 water molecules

18.1 Paper is made of cellulose fibers Paper was first made HARDWOOD FIBERS in China as early as AD 100, of mulberry bark, and then introduced to Western world by Arabs in eighth century. The first paper mills were built in spain in 11th century

The atmosphere layer is very thin compared to the size of the Earth

16.1 Water circulates through the hydrologic cycle (水文循环) The Earth's water is constantly circulating, powered by the heat of the sun and the force of gravity. Water evaporated from ocean precipitates(降水) into the ocean: direct route. Water evaporated from ocean is blown by winds until it is over the land and precipitates: (1) evaporates beck into atmosphere, (2). Infiltrate

Golden rice: two European scientists created a new strain of rice enriched in B-carotene, which the body uses to make vitamin A. This is a kind of transgenic plant(转基因植物)

The medicinal use of plants has been discovered more than 2000 years ago. Greek physician Dioscorides described the use of opium, in which morphine is the main component. In 1806, morphine was isolated from opium. In 1820, quinine was isolated from the bark of the cinchona tree