This paper introduces the conception and status of electronic Wastes, their harm to environment and human body health, their future, and the countermeasures to them.

Fire Retardant is the chemical substance which can prevent fire or flame spread. This paper introduces the kinds of common fire retardants, retarding mechanism, fire retarding treatment of materals, and the development of new fire retardants, aiming to make people know more about the fire retarding technology.

The classification and development tendency of fire retardants are introduced, mainly deaing with the fire retarding mechanism, characteristics, application and development of magnesium hydroxide as a fire retardant. It is shown that magnesium hydroxide is a new type of inorganic fire retardant which is friendly to environment.

Developing students' understanding of science essence is an important object of science education. The essential points of developing students'understanding of science essence in study of chemistry microcosmic cognition include: (1) chemistry microcosmic cognition is developing based on fact, (2) chemistry microcosmic cognition is scientific theoretical knowledge which is constructed by people to explain the microcosm of substances, (3) the rationality of chemistry microcosmic cognition attribute to that it explains and prestimate the properties of substances from microcosmic view. The basic ideas to develop the students' understanding of science essence include: (1) make epistemology thinking with the frame of WWHW, (2) construct the teaching objects of science essence understanding with the basic technology ofcrossing consideration, (3) design the teaching subjects which have epistemology meaning, (4) develop science essence understanding by dominant words, (5) develop science essence understanding by reflecting activities, (6) properly evaluate students'understanding of science essence