Planet or Plastic? is National Geographic’s multiyear effort to raise awareness about the global plastic trash crisis. Come to this page often to learn more, and find out what you can do to ...

An artificial valve is also known as a mechanical heart valve or a prosthetic heart valve. It is a man-made valve and may be composed of plastic, metal, polycarbon, and other materials. There are many ...

They are made by heating these chemicals at a high temperature. When the plastic is soft it can be poured into a mould. Once the plastic cools, it hardens into a shape. Plastic is a material that ...