Building a Rain Gauge, part 2

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What Does a Rain Gauge Really Tell Us?

Now that we know the proper shape and location for a rain gauge, lets take a look at what they can tell us, and why they are important.

Lets start by imagining that you put a rain gauge in your yard. After a rain, you find that there is one inch of rain in your rain gauge. We can use that to calculate how much rain fell on your yard.

Minerals: Streak

To perform the streak test, you rub a specimen on a piece of unglazed porcelain tile. Go to your local hardware store, and look at the backs of their floor tiles. You want a tile that is made of porcelain, and the unglazed back should have a white color.

These tiles are very hard (hardness 6.5), and they have a rough surface. As you rub the mineral across that surface, it acts like a file, powdering up some of the mineral. The color of that powdered mineral is its streak color.