There are times when words have more than one meaning. One of the most confusing circumstances is when they have completely different meanings in common speech versus in scientific and technical contexts. It can cause a great deal of confusion when these terms are used by lay persons.
I’ve read a few news articles that quoted a study and then went on to say “but this study was found to have an error in it,” when in fact, what the reporter was reading was not that the study contained a mistake but rather that the statistical analysis contained reports of what the standard error was.
A few examples are listed bellow, but I’m sure readers can think of many more.
A few examples:
- In Common Context: A mistake. Something done unintentionally.
- In Computer Science: A misread or incorrect value, usually a bit. A one where there should be a zero or vice-versa, usually the result of noise or equipment problems.
- In Statistics (and the context of scientific studies): “Error” basically means the degree of confidence of the results. In most circumstances error is calculated according to the standard deviation of data. In some circumstances error may be based on the accuracy and precision of the instrument used to make a measurement. When a study is reported to “have found an increase of 20% with an error of +/- 2%” that does not mean someone made a mistake during the study, but rather that the data indicates a increase of between 18% and 22%.
(note that the above description of error is very simplified, and in reality, statistical error is a more complex subject which includes degrees of confidence, but this is a reasonably accurate, if abridged, definition)
- In Common Context: Usually simply refers to sodium chloride, the primary component of table salt and rock salt. The majority of sea salt is also sodium chloride. Sodium chloride is that familiar “salty” tasting granular white substance.
- In Chemistry: Salt, or more accurately “salts” are an entire class of chemicals. This includes sodium chloride, but also a huge number of other chemicals. Salts are ionic compounds that can result of an acid-base reaction. Most salts are inorganic, but a few, such as acetate salts, are organic. Not all salts are white, many are not. Not all salts taste salty either, but many are toxic and thus would not be safe to taste to begin with.
- In Common Context: To grasp with thumb and forefinger in a way that can be painful or sexy.
- In Physics and Electrical Engineering: The compression of a conductor (often a plasma) by the magnetic field produced by a strong electrical current.
- In Common Context: A liquid
- In science: A liquid or gas. Most would probably not think of a gas when a “fluid” is described, but in fact, a is a fluid.
- In Common Context: A beach sandel
- In Electrical and Computer Engineering: A circuit element that can exist in one of two logical states and can be switched between those two states. Sometimes likened to a latch, a flip-flops are the basis of bit counters and used in solid state memory systems.
- In Common Context: A device for measuring time.
- In Electronics (in the context of circuit components): A pulser or a device that generates a regular timing signal for synchronizing circuit components.
- In Common Context – “Steam” is often used to describe the white misty cloud seen coming from a tea kettle or from a steam engine or the cooling towers of power plants. Even hot food that is giving off a wispy cloud may be described as “steaming.” A hot humidifying shower may be described as a steam shower.
These clouds are actually composed of tiny droplets of liquid water, so small that they may remain suspended in air and carried by currents. When large volumes of water vapor are present, some of it may condense into these tiny droplets.
In Science or Engineering: Technically, real “steam” is a vapor, an invisible gas that is entirely composed of gas-phased water. Steam may be considered “dry” if there are no microscopic droplets of water present and heated dry steam can even be used to light a match. Since steam exists at high temperatures, when it is released into the atmosphere it will rapidly condense into a mist of droplets, producing the familiar clouds, but when it does, it is no longer truly steam.
- In Common Context: It does not seem to have any consistent or coherent definition other than a belief that something is somehow “natural” or lacks “chemicals” (more on that bellow) or that something is produced by an organism grown in a manner that does not use modern technology (except for the mechanics of harvesting). The term organic is often applied to food and is increasingly applied to clothing and personal care products. Standards to exist, but there is very little rhyme or reason as to why certain things are considered organic and others are not. It appears to be primarily based on the concept of things being believed to be natural.
- In Scientific Context: “Organic” has a very concise and non-ambiguous definition. Organic chemicals are based on the covalent bonds of carbon, usually with hydrogen and often also including oxygen and nitrogen. By convention, carbides and carbon dioxide are not considered organic. Organic chemicals are associated with life and were once believed to be produced exclusively by organisms, but this was found not to be the case.Plastics are all organic, as are many industrial chemicals. Hydrocarbons, such as petroleum-derived chemicals are all organic. An easy way to identify organic chemicals: Most anything that is squishy, slimy, gooey or smelly (with the exception of sulfur-based smelly chemicals) are organic. Many (but not all) organic chemicals will rot. Most will burn. Most highly complex molecules are organic.
- In Common Context: The word “Chemical” is often used to define something artificial or possibly dangerous, toxic or otherwise fitting within the pre-conceived notion of what a “chemical” is. The term seems to have little formal definition, which results in what are essentially meaningless statements, such as “we don’t use chemical fertilizers.”
- In Scientific Context: A chemical is any substance with a fixed formula or composition. With the exception of subatomic particles, all matter is either a chemical or a combination of chemicals. A chemical can be a compound, an element or a mixture of compounds and elements. Things which are *not* chemicals would be objects composed of many chemicals. An automobile, for example is not a chemical – although it is a combination many chemicals.The use of the word “chemical” in scientific context may also indicate that something relates to the chemistry of a substance. A chemical change is distinct from a physical change and a chemical reaction is distinct from a nuclear reaction or any other kind of reaction.
- In Common Context: For most people, the term “radiation” relates to ionizing radiation, the type created by radioactive decay or x-ray tubes. It is also commonly used to describe the RF fields produced by wireless devices – this often causes a great deal of confusion to those who do not have a full understanding of the differences between the two types of radiation. The term has caused a great deal of confusion overall.
- In Scientific Context: Ionizing radiation is certainly a form of radiation, and so too is rf radiation, but so too is light and infrared radiation, like that created by a radiant heater. All forms of electromagnetic energy are forms of radiation. Radiation is also the term used to describe radiant cooling or radiant heat transfer, in which the mechanism is electromagnetic energy. Radiation can also be in the form of emissions of classical particles, such as alpha, beta and neutron radiation.Radiation is not necessarily artificial, dangerous or in any way related to nuclear energy. Indeed, all objects that are not at a temperature of absolute zero do emit some form of radiation.
- In Common Context: The word “alcohol” normally refers to ethyl alcohol or ethanol. This is the type of alcohol that is found in alcoholic beverages and is also commonly used in alcohol-based solvents as well as in medical uses such as “rubbing alcohol.” It may also be called “grain alcohol” to distinguish it from “wood alcohol” (methanol) or isopropanol, another common rubbing alcohol.
- In Chemistry: There is not a single alcohol in chemistry but rather, “alcohols” are class of organic chemicals. This include ethanol, methanol and isopropanolbut also includes pentanol and butanol. Other compounds such as glycerin and ethylene glycol are also considered alcohols.
- In Common Context: To most people the word “Theory” means something close to what “hypothesis” really means, or indicates an unproven possibility or proposed idea about something. It could also be considered analogous to “hunch” or “educated guess.” For example “My theory about why the car won’t start is that the cold temperature has caused the battery output to drop.” The use of theory in this context in common context has lead to a great deal of misunderstanding over concepts like the theory of evolution, which some would say “is just a theory,” assuming this means it is thus unproven or just a guess.
- In Scientific Context: In science, a theory is an explanation for how or why certain things are observed. Theories are based on constant logical rules which govern a system and can be used to make predictions. The hallmark of a theory is the ability to make predictions and the accuracy of these predictions is ultimately how the validity of the theory is tested.The fact that a theory is able to make some predictions accurately does not ultimately validate the theory.In some cases, a theory will show initial success in making accurate predictions in some circumstances, but will fail when it is examined more completely or is used in more varied situations. An example of this would be the ptolemaic planetary model, which makes reasonably accurate predictions of planetary motion in the short term, but cannot explain all aspects of planetary motion over the course of a longer period of time.
The theory of evolution could be used as an example of how a theory is applied. Some of the observations made included: There is a great diversity of life; many lifeforms appear to share similar structures or traits; life forms are well adapted to their local enviornment; in areas that are distinct but geographically close to each-other, it is very common to find organisms which are similar but have differing traits adapted to each enviornment; changes in an enviornment produce changes in the life forms that inhabit it. Evolution by natural selection was proposed as a mechanism which would explain all these observations, and it has since been tested repeatedly and proven to accurately predict the development of life.The greater the amount of examination and testing a theory is put to the greater the confidence in its validity becomes. However, if it ever fails, the theory will have to be either revised or rejected entirely.
Even more confusing: When terms mean different things in different fields
- In Physics: Sometimes described as the “fourth state of matter,” plasmas are superheated ionized gasses. Stars are made of high density plasmas, while low density plasmas can be found in things like neon signs.
- In Medicine: The primary component of blood. Plasma is a yellowish liquid similar to lymphatic fluid. It represents the portion of blood left after the red cells, white cells and platelets have been removed.
- In Chemistry, Thermodynamics and Mechanical Engineering: A device which converts gases to liquids. The most familiar type being found on refrigerators and air conditioners.
- In Electronics: A generally antiquated term for a capacitor. The one circumstance where the term is still commonly used being condenser microphones.
- In Optics: A lens assembly primarily used to concentrate light and commonly found in microscopes.
- In Physics: Usually means nuclear fusion of two nuclei to create a heavier nuclei.
- In Chemistry: May mean the physical change of a substance between solid and liquid, as in “heat of fusion.”
- In Biology: May refer to cell fusion.
- In Materials and Structural Engineering: refers to bonding by fusing of materials, as in welding.
If this is not all confusing enough, the phrase “the circuits were fused” can mean two entirely different things. It could mean that they were soldered together (either intentionally or due to overheating) or that they are protected by a fuse. If the circuit in question is part of a bomb, it could mean yet another thing: fused meaning armed and primed for detonation.
- In Physics and Most Scientific Context: Referring to reactions or properties of an atom’s nucleus.
- In Cellular Biology: Referring to reactions or properties of an cells s nucleus – as in nuclear DNA. This has lead to circumstances where descriptions of nuclear DNA have caused some to think that the reference was somehow related to nuclear radiation or nuclear technology.
- In Common Context (many scientific circumstances): Combustion, burning as with fire.
- In Medicine: An injury often associated with heat, but which can also be caused by chemicals (such as acids and bases) or by light (as with a sunburn), friction or ionizing radiation.
- In Nuclear Engineering: Fission. A reactor may be said to “burn” its fuel, even though it does not use combustion. This usage shows up frequently in the term burnup.
- In Information Technology: To write information to media, often implying permanently, as in “burning a CD” but also used to describe “burning a rom,” meaning to write data or a configuration to a storage chip or FPGA.
- In Aerospace: To activate a rocket engine or thruster for a period of time. This term is used even if the rocket engine is a mono-propellant rocket and thus does not actually use combustion.
This entry was posted on Monday, December 6th, 2010 at 7:34 pm and is filed under Bad Science, Culture, Education, Good Science, media, Misc. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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