Note that this page has been heavily improved with answers to many of the questions and so is only now kept for archival reasons (or if you'd like to have a bash at the questions without seeing any of the answers).
Otherwise, visit the: World's Most Unanswered Science Project

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Hi and welcome to the most interesting and useless list of un-answered scientific questions around!
You might like to visit the Light and Colour Trivia first, because that page is shorter and more digestable :)

Come back? Cool...
Everyone who's just curious about science - up to the top expert on nuclear fission/fusion will find something here.
I am looking to fill in all these questions with answers. Gradually, week by week, they will be answered - but I need your help, so if you know any of the answers to the questions below, or would like to submit a question yourself, visit Skytopia's Whirlpool of Knowledge Forum. All feedback appreciated!
Even if there is an answer already to a particular question, I would be grateful for a different view, or a different way of explaining (especially if the current answer is incorrect! but not /only/ this of course :).

The answers are printed in red and are indented for clarity.
There are 3 sections. Light, Physics and Sound. Enjoy...

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Light:

When two mirrors are facing each other, they reflect off each other infinitely producing a mirror inside mirror effect. If this was graphically slowed down, would you see a kind of build-up effect where each mirror is "drawn in"? After all, light only travels at a finite speed. Is it true that while you're still looking at the multiple reflections, millions more are constantly being made due to light travelling at only a finite speed?

If the sun suddenly went from the sky (switched off) would...? A: The place outside looks as though the sun is still there (the sky itself looks like daytime), but no visible sun was actually in the sky. B: Everything immediately blacks out. C: Everything blacks out except the sun itself. If A or C is correct, would the sun and sky suddenly turn black after about 10 minutes or gradually fade out from about 5 minutes (after the sun disappeared) to 15 mins. If B is correct, then you're saying that light travels at an infinite speed? Which 'obviously' can't be true. Surely you can't have it both ways?

If the atmosphere was taken away, you would see the sun and the black sky.
How much darker (brighter?) would Earth be:
A: With the clouds and without the atmosphere?
B: With the atmosphere and without the clouds?
C: With neither the clouds or atmosphere (just like the moon)?

When there is a half moon, you are seeing a circle cut in half. Shouldn't
there be a nice black to white (silver) gradient rather than this instant
white-one-half black-the-other approach?

Why is an eclipse more harmful to look at than just the sun?

If anyone closes their eyes, there is a random-light-mess. Is it simply 'damage' that has accumulated over the years or is some kind of brain activity? Can people who are blind also see this?

Is there a mirror or see-through film which filters out all harmful light WITHOUT looking any different?

Why is looking through a telescope at the sun more harmful than usual? Isn't it just magnifying the area, not the brightness?

There are certain types of liquids which produce their own light independently, or when mixed:
A: Can all the primary colours be obtained from these liquids or just white light?
B: If this liquid light was compressed, then would the light become stronger e.g. 500x compression = 500x light intensity.
C: If the liquid was heated to become liquid-light vapour, would the air around become luminous?
D: If the liquid was frozen, what effects would this have on the light?
E: What does the liquid taste like? Is it toxic?
F: How long does the light last for?
G: How (if?) can you 'recharge' the light?

Light bulbs have not changed much since Edison first introduced them many years ago. They all still have one thing in common though - they run out sooner or later. If they exist, how much more expensive are the infinitely-lasting light bulbs? If car lights and LEDs can last indefinitely, then surely they can do the same for the household bulbs? The perfect light bulb would be infinitely lasting, with adjustable brightness from 0 to a theoretical infinite watts (no problem, apart from the obvious heating problems and electric costs). It would also be able to glow any of the three primary colours and beyond (ultra violet, infra-red) or a mix of any of these. And would have variable size (with either circular or spherical shape). Electronic tilt'n'twist with full digital display would come as standard of course. Perhaps a configarable colour gradient display and/or colour cycle effect might add to an already incredible bulb.
Is there a light bulb which is at all close to the above description?

The light coming from a coloured light bulb is still white and therefore requires a coloured glass bulb filter to show any colour. Can coloured light come from a transparent glass bulb?

What wavelengths of light do light-bulbs emit? Is it 'coincidentally' just the RGB waves that are needed to make white light perhaps?

When you are dazzled by a bright light source and what you see becomes kind of silhouette like, is that what you are meant to see (dark picture with dazzle and back to proper detail without dazzle) or is it some kind of fault with the eye or brain?

How close is technology to this kind of microscope:
First stage: Realtime zoom in or out operation with 4-way realtime scrolling. The speed of scroll would be proportional to zoom level. Monitor display. Second stage: Same as above but with picture displayed in 3 dimensions with auto-focus and near to infinite zoom potential. Also, an enlarge option would not zoom in but simply enlarge the picture on screen. Other options such as moving and rotating the object and/or lens could be added. Perhaps a variable focus setting enabling everything or a defined distance (or anything in between) to be displayed.

Apparantly, a microscope can only zoom in so far before visible wavelengths of light become inadequate to reflect the object. Is this a fault ('fault'?) with the microscope or is it the very nature of light? If it's the second explanation that stops us from seeing closer, then isn't it possible to shine higher frequencies of light on the subject and then cycle (transpose) down the colours to what they should be?

Is there a lens which shows all parts in focus simultaneously?

At night when you look out, the sky is a sort of dull dark brown. If all street lights and lamps were switched off would the sky instantly turn pitch black?

A streetlamp at night has an aura of light around it. Is this a fault of the eye or is it just the surrounding air and dust particles reflecting light (just like fog and mist)? Or is it both maybe?

If you study the shadow of a particular object, you may find that its edges aren't sharp. This is generally referred to as a "soft shadow". Is it true that if all the light were concentrated into one point, the shadow would become sharp?

Is pure air absolutely transparent so that if you were to look off into the distance miles away, the horizon would be just as clear as the foreground? Same question with oxygen, nitrogen, helium and water.

How close are we to the kind of technology which allows sound and visual connection between two people miles apart via a 50 hz screen refresh not more than a centimetre thick?

The perfect screen display:
Completely flat, air-light monitor with adjustable size (naturally). Definable resolution and perfect screen update with all the other usual brightness and contrast controls would make a superb monitor. A 3 dimensional display could be an option too with adjustable "Z axis" stretch and start/stop point. Distance of picture and horizon could be changed in any way possible.
Maybe some kind of holographic image technology could be used here? How far off into the future is all this?

Do any of the new thin TVs have a no-flicker display (i.e. no bar rapidly moving down the screen)

Why don't they use a giant parabolic style mirror reflecting a small screen to produce a massive TV screen?

Why is everyone taught that blue and yellow make green? Extremely simple knowledge on the basics of colour should show that the actual colour is grey (white). Just because the "blue" they're mixing is more like the colour cyan, people think "Ah! yes - blue 'n' yellow's definitely green". In the same way, red+cyan and green+magenta also equals grey.

Where is magenta 'meant' to be in the colour spectrum - after blue or before red? Each end of the visible colour spectrum contains magenta/purple (red/blue mixes). It seems that:
Red ALSO (as well as its original posotion) comes after blue and... Blue ALSO comes before red.
This means that there are 1½ reds and 1½ blues in the colour spectrum!?! So what's going on? Have they had second helpings?

If you look through a yellow filter for a few minutes, everthing afterwards looks blue and vice versa. Is this a 'fault' with the eye or mind? Or is it because the sudden switch confuses the mind. Basically, are we really seeing what we should be seeing?

What kind of effect would you see if an object (with a light source) was surrounded by a mirrored sphere?
If a pulse of light was released inside a closed mirrored sphere and no energy was lost through heat, would the light remain indefinitely (evenly spread throughout the sphere) Surely not???
Also this means that if the light were to stay constantly on. The brightness inside the enclosed mirrored sphere would increase infinitely.

Is it possible to change the colour of water to black - without affecting the taste or texture?
What would water 'taste' like if it had the texture of something like plastacine or Ice-cream?!!!

What's at the far ends of the colour spectrum? Any chance of undiscovered frequencies?
Is it true that the shorter the wavelength of light is, the more chance the ray has of going through a solid object? And is it exactly proportional i.e. half wavelength means exactly double penetration?
What is the most harmful frequency?> Ultra violet or Infra red?> Radio waves or X-rays?...
Same question, except this time which is most damaging to the eyes?... I've heard that if you take the lid off a CD drive while it's on, the laser can blind you. How true is this? Is it permanent blindness?

At the same amplitude, which frequency of light is least and most harmful?

Which frequency of light from the sun produces the least heat? What frequency produces the most heat? Do certain materials prefer one frequency (say, X-rays) while another material might cook better under infra-red rays?

Could something be very hot (1,000,000°) and still have no light being emitted?
Could something be very bright and still have no heat being generated?

Physics:

Every single atom has a repelling and attractive force. Both are in equilibrium until seperated by a large enough distance. Even then, there is a very slight pull. The trillions of atoms that make up our earth and planets thus are pulling each other in. This is more commonly known as gravity. Isn't this where gravity comes from - the simple force from atoms that keeps materials together?

If the mass of the moon is low - about eighty times less than the earth, why is the gravity so high (about a third that of Earth's)?

What temperature does diamond itself melt at? and...
What temperature does the surrounding air have to reach to melt the surface of diamond?
Does it crack or burn first before it melts?

Same 3 questions with gold instead of diamond?

What is meant by 16 or 24 carat gold? Isn't it simply equivalent to the weight or density of the gold:- Does carat=weight/density?

How thick would a diamond sheet have to be to survive the force just about required to break a glass window?

How thick would a diamond sheet have to be to stop a speeding bullet passing through?

Can liquid diamond be made and if so, what temperature would be needed?

Is it possible to make an ultra-lightweight but ultra-strong object such as a diamond surface sphere? If the inside was even filled with air, the sphere would float in air and drift down slowly - very "unnatural" for such a hard object, eh?
However, if the inside was filled with helium, the object would most definitely stay afloat or even rise. Of course, the surface would have to very thin - that's why diamond would be so ideal. I wouldn't mind a floating crystalised sphere or similar in the living room as an ornament or something to play about with!!!

Can certain types of magnets in the shape of a sphere attract or repel all around the sphere equally?

Do magnets work in space? And if you were to tie a magnet parallel to a piece of metal, would there be constant force between the two which would make them start to move even from a still position and accelerate forever?

A magnet will attract certain kinds of metals, but is there some material which can naturally attract absolutely anything, without having to resort to in-built power. Any theoretical chance of this? Like-wise, is there some natural repelling material. Atoms are doing this sort of thing all the time on a much smaller scale.

Metal objects, are naturally quite cold, say 10°c. If the room was warmer, say 20°c, and you left it at that temperature, would the temperature of the metal slowly start to increase over a period of hours, days or even months to the temperature of that room, or will the metal just not go above a certain temperature?

What's the difference between the taste of water and the taste of liquid nitrogen? How safe is it to touch or even drink? Same questions with oxygen and hydrogen.
What on earth does the poisonous liquid mercury taste like? Any volunteers?
What also on earth would liquid diamond or gold taste like if it was cool enough to drink?
If one were stupid enough to dip their hand into liquid oxygen for a split second, would it eventually recover and in the short term, what would be the best course of action: To immediately soak the hand in cold or warm water perhaps?
Same questions but with liquid helium, liq. nitrogen and liq. hydrogen.

After sleeping on one's hand for example, numbness sets in followed by intense pins and needles as the cells can't get the oxygen they need:
How long can it stay without flowing blood before the hand will be paralysed? I've heard that even a few seconds without oxygen (flowing blood) will cause the cells die, but surely it's got to be more like several hours (or even days)?

After scalding your hand with boiling water, you're told to put your hand immediately under cold water. Isn't this too much of a shock. Wouldn't it be better to place the hand first in warm or moderetaly hot water, only afterwards perhaps cold?

If it wasn't for bacteria and infection, would there be any need to brush one's teeth. Does sugar itself play a part in decay.
Is it true that acid from fruit (especially lemons) is harmful to the teeth?
Is it as corrosive as sugar? If so, why do dentists not warn against such fruit?
Why can't they use the natural sweetness of an orange to sweeten food?

Apparantly, a full tablespoon of salt eaten in one go is meant to to fatal? Is this really true?

Melt glass. Super compress it. Refreeze. Instant SuperGlass???

Instead of water, could an air bomb be more useful for firemen?

Increase sea height. What would happen if it were heavy enough to collapse under its own weight?
Example: If in space, millions of tons of water were collecting in a gravity ball. The pressure would be so great in the centre eventually, that something must happen. What exactly? Would any possible explosion possibly produce light?

Is it true that the heat from the sun comes only from the conversion of light to heat?

Is the cooling effect of a fan really dropping the temperature of the room or just moving the air about?

If you were travelling incredibly fast through air, would the friction cool you down or heat you up?

How fast could you travel through air without any protection?

How heavy is air? Why does it not crush us unlike water (since we're in an ocean of it)? How heavy is fire (per cubed inch)?

Which part of a flame is hotter. The blue or orange part. Are certain colours hotter than others?

What's the temperature of a candle flame (got you there!)?
At what temperature does air ignite... as in y'know - catch fire?
At what temperature does paper ignite?

If air pressure was increased vastly inside a closed room, would objects be lighter or even float as the air is trying to get round everything. Would it be like moving through thick porridge? Same question but with low pressure.

How much pressure can air withstand? Can it can get denser and denser and still be stable? How about if any energy it did emit was also trapped, and was squashed (pressure increased) even further?

When air is compressed, it naturally repels apart when released. The suction effect does the reverse. Surely the atoms are freely roaming around - there shouldn't be any suction at all. What's actually happening, speaking atomically?

When air is sucked out of a container, 'they' say that air from outside is pushing inwards. Are you absolutely sure it's not the air from inside trying to implode rather than from pressure crushing it externally?

Water sticks and has tenacity. Is there any liquid which flows properly. Is there any possibility 'making' this kind of liquid? Isn't this what the so called 'superfluids' are?

Likewise, are there liquids that are more tenacious than water - drips that are as a large as a golf ball?
What liquid (at room temperature) can heat up most and still stay a liquid?

What material if put into a glass of water would be quickest at passing on its heat, thus averaging the temperature of both material and water? What material would be least effective at doing the above?

What happens to water if you compress it more and more and more... (It can't just disappear)?
How hot can water get if it's sealed into an air-tight container and heated and heated and...?
Is there any liquid which is close to (or even lighter than) air? Is there theoretically any possibility of this?
Is there a machine on earth that can completely fake the effects of zero gravity? Can a human enter?
As mass is all around, is there no gravity at the core of the earth? Or a kind of 360° pressure?!?
Materials are kept together because of the attractive force of each atom. Why then if two objects are touching each other do they not stick together?
Is there any material in existence that would weigh more than a tonne per cubed cm under normal air pressure? Is there any possibility of this? How fast would an object (say, a plastic sphere) need to spin to force the outer layers (of atoms) to explode? Same question with steel and diamond ball. What would it look like a million times slower? Would chunks come off or would a kind of fine mist be seen evaporating from the ball?

Measurement of mass is done with a weighing machine but in space, there is no gravity. Therefore, some kind of "Throwing machine" must be used for weighing (an object is thrown at a set speed which hits a pressure pad, calculating the mass). Is there a more sophisticated way using the radiation emitted from the object (or similar) to calculate its mass, perhaps a way without touching the object?

3 oddities about the planets:
A: Orbiting planets are always portrayed as moving in the shape of a disc. If the universe has 3 dimensions, why don't orbits move in 3D?
B: All the planets in the solar system are relatively spherical. Shouldn't they take on the shape of a rock or similar?
C: With the possible exception of Pluto, why are the orbits of planets so circular? Where are all the thin elliptical orbits?

How can you move in space if there's no air to displace?

The ultimate interactive transport invention would be a pair of discs to take you anywhere in 3 dimensions. You literally stand on them and they can be strapped onto your feet. It would be sensible for the device to be powered by a main power source rather than actual on-board fuel. The speed at which you go would be either proportional, proportionally inverse, proportionally squared or square-rooted to the distance between the two discs (totally configarable, of course) and the direction of the vehicle would be from left foot to right foot (or vice versa). This kind of transport would create an incredible sense of freedom! How far off does this kind of technology exist?

Sound

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 was 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.

When you hear someone listening to earphones, you can't hear any bass - only treble, unyet - it should be the bass you hear more because shouldn't the treble be absorbed more by the earphones' plastic etc?

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?

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?

What material reflects sound the least and most?
What material absorbs sound the least and most?

At the same amplitude, which frequency of sound is least and most harmful to the ears?

When you say something 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 (decibels and...)?

Does the volume of sound increase by double every: 3, 5 or 10 decibels? I've heard conflicting reports for each!

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?