What Is Teflon®

Teflon® is a brand of polytetrafluoroethylene (PTFE), a solid polymer that is considered to be one of the world's most slippery substances. Accidentally invented in 1938 a laboratory in Deepwater, New Jersey, in the United States, Teflon® has applications in a wide range of areas, including household goods, the aerospace industry, electronics and industrial processes. Teflon® is produced by E.I. du Pont de Nemours and Company, also known as DuPont.

History

PTFE is a fluorocarbon, a compound made up of carbon and fluorine, and it has the molecular formula (C₂F₄)n. A chemist named Roy Plunkett accidentally invented PTFE while trying to create a new chlorofluorocarbon in a New Jersey laboratory operated by Kinetic Chemicals Inc., a company that was co-founded by DuPont and General Motors. Plunkett discovered that the white, wax-like substance that was created during one of his experiments was extremely slippery and water-resistant. The substance was patented in 1941, and the Teflon® trademark was registered in 1945.

Qualities

Teflon® has a coefficient of friction against polished steel of 0.05 to 0.1, which is one of the lowest for any solid that has been measured. This makes it suitable for use in applications that require reduced friction between two solids, such as gears or sliding parts. It also is hydrophobic, which means that it repels water instead of getting wet. Among PTFE's other qualities that make it beneficial for many uses are its high melting point and its electrical insulating properties.

Uses

In the 21st century, in addition to its widespread use in manufacturing and industry, PTFE is used on all sorts of everyday items. Many people are familiar with non-stick cooking pots and pans that have been coated with Teflon®. Automobile wiper blades also are commonly coated with PTFE, which helps keep the blades from squeaking as they pass back and forth across the windshield. PTFE also is used as a carpet or fabric protector because it repels liquids, allowing spills to be wiped up without leaving a stain. It has been used on all-weather clothing, to coat eyeglass lenses, as a fingernail protector and even in a line of haircare products.

Safety

There has been some concern about the safety of PTFE, especially in cookware. In the U.S., the Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) have stated that the use of this coating on cookware and other items commonly used by people does not pose a concern. DuPont has said that Teflon® coatings do begin to deteriorate at or above 500° Fahrenheit (260° Celsius), a temperature higher than that at which most foods are cooked. Teflon®-coated pans are not recommended for cooking techniques that require very high temperatures, such as broiling.

What is an Embryo

An embryo is an organism in the early stages of development which cannot survive on its own. The precise definition of an embryo varies; in humans, for example, a fertilized egg may be considered an embryo until around the eighth week of pregnancy, at which point it is termed a fetus. The study of embryos is known as embryology, and it makes up part of a larger branch of science which is interested in reproduction and development.

The term “embryo” is only used to refer to eukaryote organisms, otherwise known as multicellur organisms. Typically, people use the term specifically to refer to diploid eukaryotes, meaning that the embryo has a complete set of genetic material from two donors. This genetic material takes the form of haploid sperm and eggs; a haploid cell only contains half a set of chromosomes, meaning that it cannot develop into anything unless it is combined with another haploid cell. As an embryo matures, it starts to turn into a recognizable form, at which point people may start referring to it as a fetus, especially in humans.

The formation of an embryo starts at fertilization. When eggs and sperm meet, they form what is known as a zygote. A zygote is a single diploid cell, created through the merging of two haploid cells. After fertilization, the zygote starts to divide, laying the groundwork for the mature organism which will eventually be born, hatched, or grown. When division begins, a zygote turns into an embryo.

Embryos cannot survive independently because they lack the tissues, body structure, organs, and so forth needed to do so. The parent of an embryo must feed it and watch out for it until it reaches viability. In mammals, this is accomplished by incubating the embryo inside the body and nourishing it with nutrients from the parents. Plants and egg laying animals provide the embryo with a rich layer of nutrients encased in a hard shell which will protect it until it is ready to be born.

The status of embryos is rather complex. Some people feel that an embryo is a life form, since it represents the potential of a living organism. Others do not regard embryos as lives, since they cannot survive on their own, and in the early stages they do not resemble anything familiar. This debate has led to conflict in some parts of the world, especially when it comes to human embryos and the choice to terminate a pregnancy.