It is possible to see a rainbow as a complete circle from an aeroplane.A litre of vinegar is heavier in winter than in summer.A barrel of juice or wine would take about a year or two to ferment naturally into vinegar.

It is easier to swim in a sea rather than in a river because the density of sea water is more compared to that of a river due to dissolved salts.

Ambulances were developed by Napolean's surgeon in his Italian company of 1796-97.The world's most expensive water is heavy water used as moderator in nuclear reactors.

TCDD is a man-made chemical which is 150,000 times more deadly then cyanide.Copper turns green when exposed to air for a pretty long time.

Nitrous oxide can make you laugh. That is why it is called laughing gas.Saccharin is 500 to 700 times more sweeter than sugar.RHTHYM is a six letter word which has no vowel.The world's first baby conceived in a test tube outside the mother's body was born in Oldham, England. Her name is Louise Joy Brown.Solid carbon di oxide is called dry ice, because when it melts it does not change into liquid but vapourises directly.

Ice does not melt when kept in liquid ammonia.Quick silver is not silver, but it is another name of mercury. It is so heavy that piece of iron floats on its surface.Perfumed talcum powder is made from mineral called Talc. It is the softest possible mineral known to man.The longest regularly formed English word is Praetertranssubstantiationalistically which contains 37 letters.

Take any three figure number in which the first figure is larger than the last, say 521. Reverse it, making 125 and subtract the smaller from the larger, making 396. Now add the result to the same number reversed, 693. The answer is 1089, and will be 1089 whatever number you start with.