"Stephen Burt" wrote in message
...
On 25 Sep, 21:10, Scott W wrote:
Evenin' all, could somebody tell me how glass rainfall measures are
calibrated ... ie how many mm of rain from a Snowdon pattern gauge
does it take to make up 1ml of water in a glass measure?

The reason being ordinary glass measures that measure as little as 1mm
are far cheaper to buy than designated rainfall measure-glasses.

Hope that makes sense...

Volume of a cylinder = pi r squared x h

Where r = radius and h - height

For a standard 'five inch' raingaguge funnel, diamter = 127 mm, then r
= 63.5 mm: and for 1 mm of rainfall (= h), then pi r2 h = 63.5 x 63.5
x 1 = 4032 mm3 = 4.0 cm3 (ml)

So if you want to measure small amounts of rainfall (the threshold of
a rainday is 0.15 mm rainfall), you'll need a measuring cylinder that
can measure accurately down to around 0.5 ml.

HTH

--
Stephen Burt
Stratfield Mortimer, Berkshire
----------------------
I find taring the container dry and then weighing on digital kitchen scales
the most accurate although mine only resolve to integer level.
1ml = 1g at STP.

Dave