Looking at sand

 

Get used to it: many of my shots have a 50-cent coin for scale: the coin is 32 mm across, and each edge is 8 mm long.

To study sand, you only need a pinch, like this picture. The coins in many of my pictures are there as a scale.

Every grain of sand has a history. The average sand grain takes many hundreds of millions of years to lose 10% of its weight by rubbing, but it slowly becomes rounded. Even so, a sand grain moving on the bottom of a river loses 10 million molecules each time it rolls over.

We won’t run out of sand though, no matter how much the grains wear away. In 1959, a geologist calculated that all through the long geological past, each second, the number of quartz grains on the planet increased by 1,000 million! Look at what you have.

Sand is made up of light-coloured rock fragments, right? Not really: take a look, even under a hand lens, and you will start to see differences.

Look out for these:
*  Look to see if the grains are angular or rounded;
*  Squeaky sand (an obsession of mine since 1947!);
*  Look to see how many different kinds of grain there are;
*  Look to see how much the sand grains are uniform in size.

From the left: sand from a bush track in Sydney; squeaky sand from Rennies beach; sand with shell grit from Coller's Beach; and hind-dune sand from Piha near Auckland, NZ.

Next, we will look at leaves. 

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