Further to my comments on Things I Don’t Know, here’s a link to a fascinating and understandable article on Krakatoa. Just because.
Here’s one excerpt to give you the flavour of it.
In all, [Krakatoa’s eruption] was heard by people in over 50 different geographical locations, together spanning an area covering a thirteenth of the globe.
Think, for a moment, just how crazy this is. If you’re in Boston and someone tells you that they heard a sound coming from New York City, you’re probably going to give them a funny look. But Boston is a mere 200 miles from New York. What we’re talking about here is like being in Boston and clearly hearing a noise coming from Dublin, Ireland.
And another . . .
The British ship Norham Castle was 40 miles from Krakatoa at the time of the explosion. The ship’s captain wrote in his log, “So violent are the explosions that the ear-drums of over half my crew have been shattered. My last thoughts are with my dear wife. I am convinced that the Day of Judgement has come.”
In general, sounds are caused not by the end of the world but by fluctuations in air pressure.
Yeah, in general. But just in case, maybe think of your significant other.
As a person with a mighty preoccupation with sound, this story provided me with revelations like no other. The inadequacy of the standard audiogram to convey the sounds we hear, or cannot hear, in normal environments does come a close second, however. Charting a 1:1 ratio of sound perception in decibels to centimeters or inches on paper to realistically render the difference between hearing sound of 1 decibel and a sound of 100 decibels would require a sheet 10,000 kilometers/6,280 miles long. That’s a Kaboom 1 billion times louder than sound at the threshold of hearing and many people hear at both extremes.
Laurna – I’ll happily take your word for it. 🙂 That disparity/range reminds me a bit of the earthquake scale, which is logarithmic (and I just found out they now prefer the “moment magnitude scale” to the Richter scale). Anyway, for every whole number you go up, the amplitude of motion (more or less, as I understand it, the strength of the earthquake) goes up by a factor of 10. (It also reminds me of an old Batman episode where Batman says some sound was “10 decibels above High C.”)
O/T sorta — the Asian Tsunami that hit on December 2003 knocked the earth off its axis by 1 inch, so Time (Greenwich Mean Time or whatever) will have to be adjusted they said to account for this.
Re Sound traveling in a high rise — last night at 11:15 until 11:20 PM, the people above me decided to do some tapping loudly on the floor. Over and over and over, getting louder. I heard the super say something in the hall. I opened the door and said to him, “Are you here to find out why those people upstairs are hammering!?”
“Uh, it was me,” he said rather sheepishly. “I was knocking on your neighbour’s door.”
(I don’t know why.)
Barbara – Ah, the all-important “why.” Important second only to an 11 PM noise stopping, I guess.