I've heard it said that a duck's "quack" does not echo. Is this true, and if so, why?Answer:
Dear Just Ducky,
The basic ingredients of an echo are a sound, a medium it can travel through, a surface capable of reflecting it, and a listener. If you have a duck, you’re halfway there. The duck’s quack is your sound and the air is the medium that will carry it.
Next is the reflecting surface. In order to produce an echo, a sound must hit and reflect off an obstruction at least half as thick as the sound’s wavelength. For example, audiologist Marshall Chasin measured the frequency of a duck quack as 2,300 Hz. The wavelength of said quack would be about six inches and therefore would require a surface at least 3 inches thick to echo from (Chasin, 2014). A quack meeting a thinner surface won’t echo.
But the inability of a surface to reflect a quack is hardly the duck’s fault, so the question remains – will a duck’s quack echo off a sufficiently thick surface, or does it possess acoustic properties that prevent an echo? Are these poor creatures truly doomed never to know the simple joy of shouting into a cave, parking garage, or racquetball court?
Science to the rescue! As word of ducks’ echoless quacks resounded throughout the world, British acoustician Trevor Cox set out to determine whether the legend was true or just a bunch of noise. Cox, a professor at the University of Salford, enlisted the help of a lucky ducky named Daisy and recorded her quacking in a reverberation chamber. He later used a computer to simulate the sounds of Daisy vocalizing in a concert hall and near a cliff. Cox’s experiments proved that Daisy’s quacking indeed produced an echo (Radford, 2003.)
We can turn now to our listener. While we listed only four main ingredients above, distance is the icing on the quack. There must be a sufficient delay between an original sound and its echo reaching the listener, otherwise he will perceive the two as a single noise. This requires that the listener and the surface providing the bounce be not too close (Albers, 1970). Further, Cox allows that a duck’s quack is actually sort of quiet and its echo can be difficult to hear. (Radford, 2003). We don’t, after all, often encounter ducks in echo chambers and concert halls. So while a duck’s quack does echo, there are many circumstances under which you might not perceive it.
Albers, V.M. (1970). The World of Sound. Cranbury, NJ: A.S. Barnes and Co.
Chasin, M. (2014). "Do duck quacks echo?" The Hearing Review, 21(11), 12. Retrieved from http://go.galegroup.com/ps/i.do?id=GALE%7CA390411907&v=2.1&u=munc80314&it=r&p=HRCA&sw=w&asid=a0efaed8a61110c4a45448d7043d11ad
Radford, T. (2003, September 8). "Quacking the myth: Acoustics professor proves ducks do echo." The Guardian (London), pp. 11. Retrieved from http://www.lexisnexis.com/lnacui2api/api/version1/getDocCui?lni=49GK-33J0-00VR-R0VH&csi=138620&hl=t&hv=t&hnsd=f&hns=t&hgn=t&oc=00240&perma=true Answered on 2015-03-25 12:24:00
I had a hornet's nest in a tree and was going to remove it during the winter months. Before it could be removed we noticed a second nest. Over the next few months the original nest started disappearing. Is it normal for hornet's to disassemble a nest? The original nest is now gone.Answer:
Dear Hassled By Hornets,
The Seeker regrets to hear that one hornets’ nest near your home petered out only to be replaced by another, but is relieved that you won’t have to deal with two active nests at the same time.
To be clear, hornets are large social wasps belonging to the genus vespa. The European Hornet, Vespa crabro, is the only true hornet species in North America (Jacobs, 2010), though several of its cousins – notably yellow jackets and bald-faced hornets – are also called hornets. Alarmed humans sometimes find their nests hanging from trees, eaves, and other protected places, though the bugs are also known to build in hollow tree trunks.
European hornets gather rotten wood, inner tree bark, and grains of soil and sand for construction materials. Other social wasps include different sources, generally other sorts of plant matter (Spradbery, 1973). They chew the gathered wood and mix it with their saliva to make a pulp, which is then added to the nest, where it dries and hardens (Edwards, 1980). Despite consulting many sources, The Seeker was unable to find any mention of hornets or other wasps recycling material from an old, abandoned nest to build a new one. Iowa State University’s Department of Entomology notes old nests can be destroyed by wildlife or weather (“Preserving and displaying a hornet’s [sic] nest,” 2005). Perhaps this is what happened to the older nest near your home.
The desire to bid rid of hornets is easy to understand: They sting! Justin Schmidt, an entomologist who studies stinging insects, created a scale to rate the pain packed by the dozens of insect species that have bitten and stung him. Yellow jackets – “hot and smoky” – and bald-faced hornets – “similar to getting your hand mashed in a revolving door” – both score 2 out of a potential 4. Slightly worse is the European Hornet – “like a matchhead that flips off and burns on your skin.” At least none of them are the pepsis wasp: “A running hair drier has been dropped into your bubble bath” (as cited in ableiman, 2008).
Many people consider hornets and wasps useful predators because they prey on other pests, a fact often noted mere seconds after you smack one with a rolled up magazine. The Seeker isn’t one to judge though, and will leave it to you to decide whether to appreciate, tolerate, or evict your winged, buzzing neighbors.
ableiman. (2008, January 29). The Schmidt Sting Pain Index [web log comment]. Retrieved from http://scienceblogs.com/zooillogix/2008/01/29/the-schmidt-sting-pain-index/
Edwards, R. (1980). Social wasps: Their biology and control. East Grinstead, UK: Rentokil.
Jacobs, S. (2010, January). European Hornet. Retrieved from http://ento.psu.edu/extension/factsheets/european-hornet
“Preserving and displaying a hornet’s [sic] nest.” (2005, July 14). Retrieved from http://www.ipm.iastate.edu/ipm/iiin/bhornets.html
Spradbery, J.P. (1973). Wasps: An account of the biology and natural history of solitary and social wasps. London, UK: Sidgwick & Jackson.Answered on 2014-12-29 10:23:53
What is Inner beauty?Answer:
A literal definition of inner beauty is not so hard to formulate. Random House Webster’s College Dictionary defines beauty as “the quality … that gives intense aesthetic pleasure or deep satisfaction to the mind or senses,” and inner as “situated within” and “not obvious; hidden or obscure” (1995). Inner beauty, therefore, is beauty that arises from within a person or thing, as opposed to from visible, outward characteristics.
When discussing the inner beauty of people, we often talk about admirable character traits, which might also be called virtues. The qualities that constitute virtue are somewhat hard to pin down, having changed over time and been shaped by the dispositions of various thinkers. Plato believed virtue to be an inner state sustained and enhanced by right and just actions (Slote, 2005). Aristotle described the ideal of the “great-souled man,” whose attributes included “a proper sense of his own worth … the desire to be honoured for his virtues by his equals (coupled with indifference to the opinion of inferiors) and in self-conscious dignity of demeanor (verging on pomposity to the modern eye)" (Taylor, 2005). Other ancients specifically identified temperance, justice, courage, and wisdom as important virtues (Slote, 2005) while later Christian philosophers elevated humility, patience, charity, and chastity (Blackburn, 2008).
Inner beauty, like all beauty, remains in the eye of the beholder, so it is perhaps up to you to fashion your own definition. If you wish to consult the wisdom of ancient or modern philosophers in your pursuit, you can find books by or about a specific philosopher by using his or her name as a search term in CardCat. For recent philosophical commentaries, you might try searching for “beauty” or “virtue” in an article database like Philosopher’s Index. And if you encounter unfamiliar terms or ideas, you can turn to a reference resource like The Oxford Dictionary of Philosophy or the Routledge Encyclopedia of Philosophy for explanation.
Blackburn, S. (2008). Virtue. In The Oxford Dictionary of Philosophy (2nd Rev. Ed.). Oxford University Press. Retrieved from http://www.oxfordreference.com/view/10.1093/acref/9780199541430.001.0001/acref-9780199541430-e-3260
Random House Webster's College Dictionary (1995). New York, NY: Random House.
Slote, M. (2005). Virtues. In The Oxford Companion to Philosophy (2nd Ed.). Oxford University Press. Retrieved from http://www.oxfordreference.com/view/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-2650
Taylor, C.C.W. (2005). Great-souled man. In The Oxford Companion to Philosophy (2nd Ed.). Oxford University Press. Retrieved from http://www.oxfordreference.com/view/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-1044 Answered on 2014-12-08 08:52:55