DUST :
Dust consists of tiny particles of solid matter that can be carried away in suspension by air. Dust is usually lifted by the wind from one place and is carried along by air currents until it finally settles because of gravity or it comes down with rain.Dust is produced by a wide range of conditions.
It may come from soil that is being blown about, from the exhaust of heavy traffic, from the burning of fuel in homes and industry and from volcanic activity, forest fires and ocean spray. Ocean spray produces about 2,000,000,000 tonnes of salt dust in the air every year.
"Dust storms" take place in areas where drought has removed natural vegetation. Such storms put thousands of tonnes of dust into the air and this dust may end up somewhere as far as 2,000 miles away
Quick Sand :
It is a light loose sand which is mixed with water. It does not look different from sand which might be right next to it. But of course there is a difference : quicksand does not support heavy objects. People who step into quicksand do not sink Out of sight. Since it contains water, they would float. And as quicksand is heavier than water, people can float higher in it than they do in water.
You will find quicksand usually near the mouths of large rivers and on flat shores where there, is a layer of stiff clay under it. Water is collected in the sand because the underlying clay keeps, the water from draining away. This water may come from many different places such as river currents or pools.
The grains of quicksand are different from ordinary grains of sand because they are round instead of being angular or sharp. The water gets between the grains and separates and lifts them so that objects tend to flow over one another. This makes them unable to support solid objects. Some quicksand is not even made of sand. It can be any kind of loose soil, a mixture of sand and mud or a kind of pebbly mud.
One has to move slowly in quicksand if one steps into it. This is to give it time to flow around the body. Once one does this, it will act like water in which one is swimming - ( need more check quick sand properties @ wiki).
Quick Sand Pictures :
Quick sand images
