Sound

Listening
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For the last few years in the U.S. we have had commercials so loud on television that they actually hurt your ears. I wondered why even the sponsors didn't realize that this was so annoying that people push the mute button to save their ears. Here is something that I didn't know. Regulations state that a commercial can be as loud as the loudest event in the program you are watching. If you are watching a war movie with loud explosions, the commercial will be as loud as the loudest explosion. It is hard to believe, but it is true. This is enough to put people off from watching these types of programs. Fret not though, because legislators are going to try and put a stop to all this volume by creating new rules that state that a commercial can only be as loud as the average sound volume for the program you are watching, not the loudest. Thank goodness, common sense might even prevail.

Loud TV Commercials
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Sound is a strange thing. It is an oscillation of pressure that is transmitted through a solid, liquid or gas. While light is scooting along at about 186,000 miles per second, sound is taking its time and travels about 700 mph give or take about 50 mph depending on the altitude where the sound was created. We as humans have only a limited range of sound that we can hear. It ranges between 12 Hz to 20,000 Hz, but most of us can not hear this entire range and as we age the range that we are capable of hearing shrinks. This gives rise to a very interesting phenomena and that is enjoyment of music. If a young person and old person hear the same piece of music, the older person may not be able to hear some of the subtle sounds that the younger person can, thus reducing the older person's ability to appreciate the piece.

One of the amazing things about sound is how it can travel through a solid. If one taps on a brick wall hard enough, a person on the other side can hear it. The sound can actually travel through the bricks, yet if I shine a flashlight on the wall, no matter how powerful the beam, the beam can not be seen on the other side. Sound waves have certain properties such as amplitude. Amplitude is basically how loud the sound wave is. If I shoot a gun off next to you, your ears might ring and you might not be able to hear on that side of your face for awhile, but if I am chewing bubble gum next to you and pop a bubble, you are in no danger of going deaf. Building are built with the conduction of sound in mind. An example of this are some of the ancient Greek arenas. They were built so precisely that no matter where you sat, you could hear the speaker without aid of any devices.

It seems that the ancients knew something about the property of sound. In some ancient battles the soldiers would scream at the top of their lungs when plunging into battle. The sound was supposed to scare the other side into running. We used to think of sound as just a byproduct of life. There are animal sounds, mechanical sounds and human sounds. Then there is the sound from a strong wind, or the waves lapping up against the shore. There are violent sounds such as those from hurricanes, tornadoes and volcanic eruptions. Perhaps the worst sounds of all are the sounds of war. In the old days no one ever thought of using sound as a weapon, except for the occasional firecracker behind the chair routine. That has all changed now.

Some ships have actually began to deploy sound weapons. This was prompted by the pirate attacks form Somalia. Ships that go close to this country have become easy pickings and there is not much risk to the pirates, because the international community that is using their ships to police the area set the pirates loose if they are captured, because they claim that they don't have the authority to detain them. Don't look now guys, but I don't think that anyone would complain if you did lock these people up, but I am getting too far afield. Some ships now contain a sonic cannon that puts out sound waves so powerful that you can not function if you are in the path of the cannon and this is precisely the idea. When it is aimed at the pirates they have to turn away to get away from this painful sound.

Sonar
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If a generated sound wave is strong enough it can actually cause shortness of breath. They can pass through building and come out the other side. We are talking about very powerful sound waves here, not your average sounds. The question has often been asked, if sound can kill? It is said that during World War II the Germans built a huge sound machine just for that purpose, but its range was so limited that it had no practical battlefield use and besides that point, there were a lot more efficient ways to kill, than having to set up a huge speaker system that doesn't have much of a range. Sound is one of those things that we can't see, but sometimes we can feel the pressure from the waves if we are close enough to the speaker and they are large enough. Not all sound acts the same way. Take sonar for example. I bet you don't know what sonar stands for? It is Sound Navigation and Ranging. Sound is sent through the water and bounces off a target and is sent back to the sender. That is how things like submarines are detected under water. Sonar can also be used in the air to help robot planes and such to navigate and yet all we are talking about is a type of sound wave.

Some people believe that there is another type of sound, a sound that can not be heard by human ears, but can be recorded and played back. This type of sound and recording is known as Electronic Voice Phenomena. There are those that swear that it is legitimate and that spirits can leave us messages this way. The Internet is chock a block, as they say, with these recordings. The way that most of us record sounds in now digital. The sound is represented by 0s and 1s and then reconstructed. In some areas on earth there are sounds that are driving some people crazy. In these areas only about 20% of the population can hear them and claim the sound is like a hum and never stops. I remember hearing stories about people picking up radio stations in their fillings. Sound is something that normally we are lucky to have, without it we couldn't have any verbal communication, the animals couldn't use it to attract each other or warn off each other. Sound is one of the basic things for life on earth and it is far more complicated than we first suspected.