Tuesday, August 2, 2011
Many scientific terms are also used to describe everyday experiences. In doing so the scientific meaning of those words is often lost or distorted.
Common usages are usually innocent attempts by people to characterize the unfamiliar. If the terms are abused, it is not intentional.
More onerous is using these words to gain credibility for poorly conceived ideas. Then, there are the despicable few who deliberately shroud nonsense in the language of science. This is done to hide an agenda promoting ideas that have no substance.
Let's examine a few of the most commonly misused words: energy, force, and field. Science has precise definitions for each. Moreover, each is quantifiable. They can be measured unambiguously in units established by the scientific community.
We all have said something akin to, "I just don't have any energy today". That's innocent enough. We all recognize the meaning of the statement. No one is offended if it doesn't meet standards of scientific usage. No harm, no foul.
Advocates of extra sensory perception often claim to "feel someone's energy field." They speak of energy transmitted through emanations or auras. It isn't clear what is meant by either energy or field in such statements.
It seems words that sounded good have been simply plucked from indexes of physics books. The usage is totally uncorrelated with any scientific concept.
Rigorous tests have failed to demonstrate humans have energetic or field-like properties or capabilities remotely resembling the claims of ESP advocates.
Such vague associations are motivated by no purpose other than to make the claim sound credible. If one understands the rigor behind new scientific discoveries, these abuses are particularly irritating.
Such claims make it harder for the general public to discern real science from flimflam. Perhaps there is no ill will toward science, but merely an attempt to exploit the credibility of science for personal gain. Maybe no harm is meant, but there is truly a foul.
Finally, because the scientific approach doesn't favor their agenda, there are those who knowingly undermine the public's understanding of science. These are typically people or organizations championing a cause. This is a topic by itself, so, I won't belabor it here.
Suffice it to say, unlike the operation of science, they know what answers they want and ignore conflicting data. Often, they cynically display the trappings of science; use the words of science, but work to undermine it. Truly, harm intended, and damage done.
Let's look at the scientific meaning of the word force. There are only four fundamental forces: gravitational, electromagnetic, weak and strong. Each is a phenomena arising from the properties of fundamental "particles." They are mediated (transmitted) by other fundamental "particles" with amusing names; gravitons for gravity, photons for electromagnetism, bosons for weak, and gluons for strong.
Whatever their fundamental nature, forces cause displacements of the uniform paths or trajectories of objects. Newton helped us understand that objects in motion stay in uniform motion unless acted on by forces. A rocket engine accelerates a rocket. That change in velocity is acceleration. Its Newton's second law: F=ma, force equals mass times acceleration.
When a force causes an object to be displaced, the object has energy imparted to it. If the object's speed changes, then its kinetic energy changes. Mathematically, kinetic energy is an object's mass time its speed squared.
Alternatively, the displacement may have moved the object to a new location in a force field, changing its potential energy. Fields and forces are intimately related. There are only four kinds of fields, each having the same name as their associated force.
Going back to more familiar usage, for convenience we talk of using force when pushing on a pry bar, centripetal force when spinning an object around on the end of a string, or frictional force causing something to slow down.
At a fundamental level, these are all different manifestations of the electromagnetic force. Whatever the common usage to characterize forces, they all arise from one of the four known forces.
Likewise, energy can be used to do work. It is extracted from a source by exploiting changes in either the kinetic or potential energy of that source. "Chemical", "electrical", and "fossil fuel" energy are among the most common energy sources. Each of these exploits changes in atomic energy (electromagnetic) states of the material being used.
Extraction of "hydroelectric energy" exploits the difference in gravitational potential energy of water stored behind a dam at a height above downstream elevations. "Nuclear energy" ultimately comes from changes in (potential) energy states of atomic nuclei. These states arise from strong force interactions in the nucleus.
Force and energy have units, newtons and joules, just as distance or time have units, meters and seconds. Each is measurable. The relationships between different observables are understood. There is no confusion about what the terms mean.
It is not wrong that we have colloquial usages for the same terms used by scientists, but it can lead to confusion. And, in some cases, the public is susceptible to being misled by those with personal agendas.
Steve Luckstead is a medical physicist in the radiation oncology department at St. Mary Medical Center. He can be reached at firstname.lastname@example.org.