Well on our last stop on sound and waves we discuss some very neat applications. Our last guest will be Dr. Docteur. There he is right now. (How convenient) "Hello Doctor, can I ask you some questions?'

"Of course you can, but only if you promise to remove your hat."

"Do I really have to?"

"Yes you do, I can't concentrate with that thing in front of me."

"All right then."

" You're bald!!!! So that's why you wear that hat! "

"Have you had your fun already!

"Yes, yes, I'm all right."

"Okay then, could you please give us some applications of sound and waves?"

"No problem. Well I guess the most common example is the ultrasound. You've heard of pregnant women having an ultrasound.An ultrasound bounces sound waves off of the baby, and the reflected waves reflect back at different speeds. These reflected waves are processed to give an image of the baby. Now ultrasounds are not only used in checking babies, but they also are used to check inside other precious equipment and objects. It is a very valuable tool for looking inside something without touching it. By the way ultrasonic means frequencies of sound we can't hear through our ears. (greater than 20,000 Hz)"

"Very interesting Doctor Docteur. Now could you tell me what sonar is?"

"Sure, sonar is an application of echo. Say you have a boat in water. With sonar, waves are continually sent to the ocean floor from the boat, and time of arrival for the waves is noted. Now if something gets in between the boat and ocean floor, the waves are reflected back to the boat in less time (less distance to cover) Hence you can find out if something, say a submarine is below a navy boat."

"Wow! Tell me more!"

"No problem. I'll tell you about something that will be music to your ears - a speaker. As you should know from previous discussions (I hope!) sound is a wave. Now what speakers do, is that they take a signal from a stereo and translate them into a series of vibrations. The speaker then takes these signals and vibrates the air exactly how the recorded track should sound. So the speaker vibrates the air in such a way that we hear the vibrations as sounds we recognize, say a song or a speech. That's why a speaker that can output a lot of base can give you a thumping feel in your chest. The speaker is pushing the air towards you. A neat little experiment you can try is to place a piece of paper near the speaker and see what happens to it." "

"Thanks a lot Doctor Docteur. C'est un bon experience, n'est pas?"!

"Doh!" This is is the last section about sound and waves, I hope this has been a totally loud experience for you! It was for me!.

Sound can be applied to odd many things, such as ultrasounds, and Sonar.

Quiz