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.

What Is Rust

Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. Although some people refer to rust generally as "oxidation," that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.

The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. 

If sodium is present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly.

Some pieces of iron or steel are thick enough to maintain their integrity even if iron oxide forms on the surface. The thinner the metal, the better the chance that rusting will occur. Placing a steel wool pad in water and exposing it to air will cause rusting to begin almost immediately because the steel filaments are so thin. Eventually, the individual iron bonds will be destroyed, and the entire pad will disintegrate. 

Rust formation cannot be stopped easily, but metals can be treated to resist the most damaging effects. Some are protected by water-resistant paints, preventative coatings or other chemical barriers, such as oil. It also is possible for one to reduce the chances of rust forming by using a dehumidifier or desiccant to help remove moisture from the air, but this usually is effective only in relatively small areas. 

Steel is often galvanized to prevent iron oxide from forming; this process usually involves a very thin layer of zinc being applied to the surface. Another process, called plating, can be used to add a layer of zinc, tin or chrome to the metal. Cathodic protection involves using an electrical charge to suppress or prevent the chemical reaction that causes rust from occurring.

What is a Metric Ton

A metric ton is a unit of measurement based on the metric system, rather than the standard system used in the United States. A metric ton is equivalent to 1,000 kilograms, and is strictly speaking a megagram, being one million grams.

The word most likely comes from the Latin word tunna, which is a word for a cask. Since a large cask full of something would weigh roughly a metric ton, this origin is commonly accepted. The word has been in use for quite some time, although previously the spelling was more often tunne.

The metric ton is often spelled as tonne, and in the United States may also be called a tonneau. A metric ton is not to be confused with the short ton unit, known simply as a ton in the system used in the United States. This ton is equal to 2000 pounds, or roughly 907kg. It should also not be confused with a long ton, a unit no longer in common usage in the United States, which is equal to 2240 pounds.

The official symbol for the metric ton in the International System of Units (SI) is simply ‘t’. Although all of the standard prefixes can be used with the metric ton, in practice the most common ones are the same ones used with the short ton. The kilotonne and megatonne are the only two units commonly seen outside of the metric ton itself. 

Kilotonne and megatonne may be used as metric for measuring energy release. This makes use of the metric ton by connecting it with the explosive TNT, as a way of calculating the force of an explosion. A metric ton of TNT releases roughly 4.19 X 10^9 Joules of energy, with a kilotonne releasing 4.19 X 10^12, and a megatonne releasing 4.19 X 10^15. To put this in some context, the Hiroshima bomb was equal to about twenty kilotonnes of TNT, while a modern nuclear missile could fall closer to the twenty megatonne range.

Because of the similarity in pronunciation — and in some circles, spelling — there can often be confusion between a short ton, a long ton, and a metric ton. In general, in the metric-using world the term ton or tonne alone will be used to refer to a metric ton, while the distinction long ton or short ton will be used to refer to the measure of the standard or Imperial system. In the United States, the term ton will be used to refer to a short ton, although in some industries — such as freight — a ton may be assumed to be a long ton. The term metric ton is then used to distinguish the metric unit. As a rule of thumb, it is a good idea to distinguish which unit of measurement you intend, if there is any doubt that your listeners might misconstrue your meaning.

What Is Rust

Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. 

Although some people refer to rust generally as "oxidation," that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.

The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. 

If sodium is present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly.

Some pieces of iron or steel are thick enough to maintain their integrity even if iron oxide forms on the surface. The thinner the metal, the better the chance that rusting will occur. Placing a steel wool pad in water and exposing it to air will cause rusting to begin almost immediately because the steel filaments are so thin. Eventually, the individual iron bonds will be destroyed, and the entire pad will disintegrate. 

Rust formation cannot be stopped easily, but metals can be treated to resist the most damaging effects. Some are protected by water-resistant paints, preventative coatings or other chemical barriers, such as oil. It also is possible for one to reduce the chances of rust forming by using a dehumidifier or desiccant to help remove moisture from the air, but this usually is effective only in relatively small areas. 

Steel is often galvanized to prevent iron oxide from forming; this process usually involves a very thin layer of zinc being applied to the surface. Another process, called plating, can be used to add a layer of zinc, tin or chrome to the metal. Cathodic protection involves using an electrical charge to suppress or prevent the chemical reaction that causes rust from occurring.

What is Viscosity

Viscosity is a scientific term describing the internal friction of a fluid or gas. Both have adjacent layers, and when pressure is applied, the friction between layers affects how much the substance will respond to external force. Viscosity, in its simplest form, can be evaluated by the thickness of a substance. A general rule is that gases are less viscous than liquids, and thicker liquids exhibit higher viscosity than thin liquids.

Viscosity may also be described as resistance of a liquid to penetration. Some refer to viscosity as the density of a liquid or gas. The term fluidity is opposite to viscosity, as it measures lack of resistance instead of amount of resistance.

Within each substance, the molecules reduce flow. They collide with each other, and also exhibit a degree of attraction. Molecular analysis can help determine specific viscosity measurements, thus helping to determine which substances will be of most use in a given application.

Temperature also effects viscosity. Raising the temperature of a fluid tends to make it less viscous. If one takes a thick liquid like molasses, and heats it up to boiling, the result will be a thin, easy to pour liquid. Cooking oils that are refrigerated, in most cases become more viscous, or almost solid due to colder temperatures, rendering them useless.

As crude oil is piped through climates of varying temperatures, the rate of flow in response to pressure changes. When oil is derived from Alaska, it is more viscous, than oil derived from the Persian Gulf, since the ground temperatures vary significantly. To address the issue of force needed to deliver oil through piping, sensors in some pipes measure the viscosity of the fluid and determine if greater or lesser pressure must be added to keep the flow of oil constant and steady. 

Naturally, motor oil is also subject to changing viscosity when heated by an engine. Oil that becomes too thin from the engine’s heat will not work properly in the car engine. To address this, scientists developed additives, called polymers, which keep viscosity rates constant under higher temperatures. 

Geologists use measurements of viscosity to evaluate magma under active or possibly soon to be active volcanoes. When magma exhibits a low level of viscosity, the volcano is more likely to erupt, because little pressure is needed to push the magma to the surface. Magma with greater viscosity causes volcanic eruptions less frequently. However if an eruption occurs with high viscosity magma, it results in huge explosions, since greater force is required to push magma outside of the volcano.

What Is Glycerin

Glycerin is a thick liquid that is colorless and sweet tasting. It has a high boiling point and freezes to a paste. Glycerin's most common use is in soap and other beauty products like lotions, though it is also used, in the form of nitroglycerin, to create dynamite.

This liquid is popular in beauty products because it is a humectant — it absorbs ambient water. This means that it can help seal in moisture. Not only is it used in the soap making process, it's a byproduct too. Many soap manufacturers actually extract glycerin during the soap making process and reserve it for use in more expensive products. 

Even when soap manufacturers extract glycerin, however, some amount remains in every bar of soap. Additional may be added to a bar of soap in order to produce a clear finish and extra moisturizing qualities. The extra also enhances the cleaning aspect of soap.

Glycerin can be dissolved easily into alcohol and water but not into oils. The pure chemical element is called Glycerol, which indicates that it is an alcohol. The impure commercial product is called glycerin.

The fact that is also easily absorbs water from the surrounding air means that glycerin is hygroscopic. If you were to leave some in the open, it would absorb water from the surrounding air to eventually become 20% water and 80% glycerin. If you were to place a small amount of pure glycerin on your tongue, your tongue would blister because it is dehydrating. When beauty products containing glycerin are used on skin that is well moisturized, it can help keep that moisture in. Where we get glycerin has changed over time. In 1889, for example, commercial candlemaking was the only way to obtain glycerin. At that time, candles made from animal fat which served as the source of glycerin. Extraction is a complicated process and there are various ways of going about it. The simplest way is to mix fat with lye. When the two are mixed, soap is formed and glycerin is then removed. Still, a small amount of glycerin remains in the soap. Glycerin has a variety of uses. As stated above, it can be used to make dynamite. It is not explosive alone, however, and it has to be processed before it can be used as an explosive. It's also used in prints and inks, preserved fruits, lotions and as a lubricant. It can also be used to prevent hydraulic jacks from freezing. Its antiseptic qualities permit its use in the preservation of scientific specimens.