The most common sort of dust is the sort you wipe off tables and shelves, but this isn’t the only sort by any means. Dust is tiny particles of solid matter, which are so light that they can be blown about by air currents. Almost everything produces dust, even the sea. This sea dust takes the form of salt dust, caused when sea spray evaporates in the air and leaves tiny particles of salt flying about. This is why when you are at the seaside, and the wind is rough, causing spray you can taste the salt in the air. You’ve probably heard of dust storms, which happen in dry areas where the lack of water means that plants and grasses don’t grow. The dust on the ground is blown about by the wind, and can be carried for miles, in fact, dust from the Sahara Desert has been known to fall on London. Did you know that you can actually see dust as it flies about?
You see tiny particles of something moving about in a beam of sunlight these are what is called dust ‘motes’, and by trying to count them you can see what a lot of dust there is in the air.