The World's most unanswered science questions:
Everything to do with Sound - waves, transmission and even music - is covered on this page. Before diving straight into the questions, here's a quick table showing the special symbols and what they mean.
This symbol means that the question is difficult to find out in practise. However, through lateral thinking and common sense, an answer is possible.
This symbol means that the question is nigh-on impossible to verify by experiment alone. However, through lateral thinking and common sense, an answer is possible.
This symbol means that the question is delving into the theoretical realm and is once again difficult to test. The answer/s are possibly right - but not guaranteed!
The ultimate! Questions with this symbol push the boundaries of theoretical knowledge - and are nigh on impossible to verify by experiment. Any answers are based on our current understanding of the universe - and thus are subject to error.
Planes and sudden over-head sound
When a plane is coming from a far distance, one moment you can't hear it, the next, the engine suddenly becomes heard. Why not a gradual increase in volume? Is should fade in gradually - surely?
This all depends on the direction of the plane and its speed. If the plane is heading in your direction (laterally, not on the Z axis I hope!), and it's travelling near the speed of sound, then the 'fade in' is going to be much quicker than the longer lasting 'fade out'.
The plane is constantly 'chasing' its own sound and so the pressure of sound is much greater on approach than retreat. If the plane was travelling at the speed of sound precisely, then one moment you would hear nothing and then absolutely instantly - it would be very loud! [editor]
The tinny earphones conundrum
When you hear someone listening to music via headphones, you can't hear any bass - only treble. One would think though that the bass would be louder (since the treble should be absorbed more by the earphones' plastic etc). Why then are ear/head phones so 'tinny' from a distance?
A perfect melody?
In music, is there such thing as a perfect melody, rhythm or chord sequence?
Maybe. Or maybe there are dimensions of perfect melodies. I only know that for every good melody/harmony that could exist, there are thousands/millions of potentially bad melodies. [editor]
For a further breakdown of whether music can be rated outside of human opinion, visit the Aesthetics of music page.
How does something sound in...
What difference would be made to the sound we hear if:
A: The air pressure was twice as great?
B: The air pressure was half as great?
C: The temperature of the air was just above absolute zero?
The stereo effect and gauging direction
Is the reason why one can recognise from what direction sound is coming from because sound reaches one ear fractionally before the other? What difference(s) would just one ear make?
The perfect 'sound-ometer'
Is there an instrument that can measure the level of sound and display the results in a kind of disc which gives information on the intensity, direction and perhaps distance in a either a digital or graphical format?.
For example, the east edge of the disc would glow brighter if sound were coming from that direction. Maybe even a spherical version of this could be made. Again, the data could be represented graphically with glowing "mountain ranges" appearing on the surface of the sphere.
Sound absorption materials
What material reflects sound the least and most?
What material absorbs sound the least and most?
Give comparisons with other everyday materials (and diamond)
Loss of sound energy through heat
A very minuscule (but no doubt there) amount of sound is converted into heat when travelling through air. What percentage exactly?
Deadly sound frequencies
At the same amplitude, which frequency of sound is least and most harmful to the ears?
Would these levels be proportional to the apparent 'loudness' to our ears?
What's the deal with the alleged 'dangerous' frequency at approximately 7 Hertz?
The decibel and its measurement
If a particular measure of 'loudness' is 50 decibels, is that referring to the source's actual output or from what you hear standing at a particular distance?
What would be the name of measurement for both of these types of measurement (decibels and...)?
Googleplex of volume(Yes I know it should be spelt "Googolplex" :-P )
Is there a theoretical limit to how loud something can be (in physical and perceptional terms)?