I like to study history and do my personnel research on historical
development including technological development during my free time.
Through my observation , study and personnel research I noticed that
the development of our society is
closely linked to development of materials science and materials engineering.
The ancient Chinese Believed that 金木水火土 (Metal , wood, water ,fire
and earth are the essentials of the world? It is part of a universal
truth(理).Fire represents energy is things that we can not live without
, we need energy that we derived from oxygen to carry out our
activities every second , fuel in the form of fossil fuel , solar
energy ,hydropower ,wind power , nuclear energy are required for
generation of electricity for industrial and domestic use. Also fire could be regarded as radioactive element that can be  the efficient way of generation of energy.  Wood or
carbon based compound provide usfood , cloth , Shelter Home, and cart for transport cargo.
Earthenware are use have been used container for ornamental purpose ,clay and brick which are essentially composed of earth until todayare used as building materials. Metal which was used in the past formaking weapon is widely used today to make industrial machinery ,industrial component ,domestic utensil , and building materials.
Fire which represent energy is the essential that we need s every
seconds . Wood support lives since the first existence of living
being, earth are materials that we depend for as a building material
since primitive time , the technology of metal refinement and metal
alloying is always accompanied by a significant break through in
technological development.
Are Metal , wood, water ,fire and earth, these five essential still
relevant to us today but they are still used today as industrial
materials and are known as
i) Ceramic and glasses ,ii) Polymers ,iii) Metal alloy , iv)Fuel
The ancient Chinese apart from believing that the five elements of
metal , wood , water ,fire and earth are the essentials of the world ,
also believe that these five these elements could annihilate or supplement and complement each other under the right conditions

According to rule of  formation and annihilation of WU XING (five elements), metal goes into liquid during corrosion , water goes into wood , wood goes into   fire , fire  goes into earth, earth  goes into metal.

From the modern scientific point of view this is true because metal cannot cut water and it  give rise to the corrosion product in liquid form during corrosion , water with mineral content assist the growth of wood , wood is used as fuel to support combustion , a hot temperature is required to turn watery clay into earthen ware  and metal is not its pure form but always associated with earth.

Metal overcomes wood , wood overcomes earth , earth overcome water , water overcome fire ,fire overcome metal . This is also true because axe or other tool made of metal is used to cut tree, wood  are grown to  protect the earth in order prevent flood , also we need water to quench our thirst  and we also need fire to refine metal.

For metal container of the right shape and size sufficient amount of metal need to be melt by fire

Water can give rise to liquid , when liquid is abundant metal will settle ,a metal that has been  properly tempered  with water will become  less brittle .Metal can used to cut down tree ,however will lose its effective sharpness after cut down too many trees. Metal depend on earth for its formation , when earth are abundant metals is hidden below , when too much mineral are present ,the quality soil changes.  A growing fire  in the presence of water complements each other. Fire assist the formation of earthen ware

 

For these reason materials in the form of  WUXIN  ( five elements) should be handled cautiously to sustain development to avoid tragic., when too much earth is present fire will turn weak, a strong fire will stop growing when sufficient amount of soil is present. Fire can melt metal ,but too much metal is present fire would extinguish , when metal is not strong it could easily be melted. Fire depend on wood to grow , when wood is accumulated  in the presence of fire the fire grows , too much fire would make wood burns. When too much water are accumulated in the earth , a pond is formed. Water assist the growth of tree , when too many tree exist water level reduce, a strong water flow can be stopped by trees. Water  can overcome fire ,  when fire grows big water quickly dry, when fire is weak  it can be extinguished. Liquid depend on metal for its existences , too much metal  the liquid become cloudy, metal contain water but too much liquid cause metal to settle. When earth become abundant it needs water to facilitate the flow. Earth assist the formation of metal  ,too much metal alters the nature of soil. A strong earth needs metal to form into a container. Earth can overcome the water and contain it , when too much water is present  earth is carried away, when water flow is weak in the presence of earth , clog occurs.

Earth depends on fire to exist , when fire is too strong scorch occurs , fire assist the formation of earth , but when too much earth is present fire become weak. A tree need to cut by metal tool to form into a  column of the building. Wood assist the formation of fire , a hard wood need to be

seasoned or tempered by fire. Wood can overcome earth , but when earth is too much the three torn , when earth too weak it penetrate earth can cause impression / depression. Wood depend on water to grow , too much water will cause wood to flow, water assist the growth of tree , however too much tree will reduce the water level.

For  example in  ancient time the Chinese ruler lay a strict rule to allowed tree to be cut down during a certain period in the summer , to ensure the sustainability. Green Technology and
Sustainable development is indeed not new to us but has been practiced since ancient time.

Would not be good for us to do learn from our wise ancestor applies it to our green technology to ensure the sustainable development of our world.