Brain Teasers

[Taliesin]

I think it has to do with wave motion, like the pebble dropped in a pond, but I'll admit I'm drawing blind here. I'm lousy at physics.

This doesn't have much to do with theoretical physics. The problem is very down-to-earth and doesn't need any equations to show what is wrong.
For a clue we would say: if we had done the experiment, the time would have continued to shorten. There would be no jolts in the graph.

[RobinHood3000]

Would the trend be the same if he used a method other than a gun to create the sound?

[Taliesin]

Yes, we think so.
The gun, or method of making the sound is irrelevant.

[Pendragon]

Now he smacked a bear? That's what I get, but it's probably a little more complex.

Hee. Actually it's a little less complex.

[Pendragon]

Okay.

Here is a story we heard on a science day.

This is a real story. And is not based on word play.

Quite long time ago, about in the beginning of the previous century, there was a concert hall in some city in America that people wanted to improve or something like that.
They employed a physics professor to work on the acoustics.
The professor was quite a serious man and did the following experiment every day, many times:
He built a wooden soundproof box in the concert with a hole on top. He went inside that box with just his head out. He fired a gun inside the concert hall (he probably pulled a string attached to the trigger or something like that) and measured the time of the echo (well, how long the echo lasted). He did this experiment every day and his results were quite strange - which can be seen on the following graph - the echo time first shortens slowly and then jolts suddenly upwards. Then it starts all over again.
The interval of this period is fourteen days.
What is the reason behind these strange results?

The graph is an added image, but it is not exact - it was quickly done. (the y axis shows the time in seconds the echo lasted and the x-axis shows the days)

Just so I understand correctly, Tal, the box is soundproof, but his head isn't in the box but sticking out? And you say it doesn't matter what makes the sound, the results will be the same or similiar. Hummmm. I'm debating on that box. Why in heaven's name would you build a soundproof box for your BODY to get into, when your head and ears are outside the box? Vibrations-- is that the answer?

[Pendragon]

No comfirmation or denial? Hummmm.

What does this say, read correctly?

nowhsmackdabere Hee. A good one, I think!

Well, mine is very simple. It is an expression often used in the South.

The word seperates like this NO smack dab WHERE. So you have an old expression used often to describe being lost, or hard to find: It was smack dab in the middle of nowhere!""

What Tal's is, I don't know.

[Taliesin]

Just so I understand correctly, Tal, the box is soundproof, but his head isn't in the box but sticking out? And you say it doesn't matter what makes the sound, the results will be the same or similiar. Hummmm. I'm debating on that box. Why in heaven's name would you build a soundproof box for your BODY to get into, when your head and ears are outside the box? Vibrations-- is that the answer?

No, we wouldn't say "vibrations" were the answer.

You would leave your head and ears out so that you could hear when the echoing stopped. The box mirrors sound so that is why you need to get into it.
The problem is not in the method of the sound.

We hope that you haven't misunderstood the graph - it is like - (these figures are not accurate, but they should give the right impression) on the first day the average time of the echo was 15 seconds, the second day 14.95 seconds, the third day 14.87, fourth day 14.8, fifth day 14.7 et cetera until on day 13 it is 13.1 and on day 14. it is 13.0 and on day 15. it is again 15 seconds.
It has quite a down-to-earth answer, really. Come on, you can guess it.

[Madhuri]

Is it that, the echo has this range, and after it has touched all the values, it comes back to its first value.

I know its a foolish answer, but a guess.

[Pendragon]

You may be on to something, Maddie. Pitch and range of sound might hold the answer. When the echo reaches a certain range, the human ear can not longer detect it. But if the pitch and range has not really changed, he has grown accustomed to it, then when it would seem to pass out of his hearing range, it comes back to normal? Am I making any kind of sense here?

[Madhuri]

Okay until Tal replies, I'll ask one.

How to cut a circular cake into 8 equal pieces?

[RobinHood3000]

Three full diameter cuts, spaced equally?

[Madhuri]

I dont think so.

[mir]

eat all but 8 crumbs?

[Madhuri]

he he he...good idea

BTW, it is an interview question.

[AimusSage]

divide it into four equal pieces, than slice the cake in half.