Pat has made the very obvious practical and useful observation that 1 mm of rain per square meter is one litre. Meteorologists and the public don't seem to get the message to "Make Metric Meaningful"
Also in Pat's example, 27 500 litres of water are 27.5 tonnes or 27.5 cubic metres. This is why the SI was developed. These relationships are not taught now to make them meaningful. This is particularly true in the United States. The SI and the ISO date/time standard and these relationships should be the first thing which ALL science teachers should know and teach first. The SI is the ABCs of science and technology much like we learn (memorize) the ABCs for English and other languages so we are able to read and write. Schools in the US teach how to convert from English to metric and metric to English in math class. They don't teach kids to think metric and to apply it practically. It's just another measurement system or a bunch of numbers. The SI diagram shows these relationships very well. It should be the first thing taught to teachers and kids since it provides a foundation upon which to build for all science and technology. At my suggestion and through the acceptance and commitment by Dr. Jerry Weast, Superintendent, "Make Metric Meaningful" was introduced into the 140 000 student Montgomery County Maryland Public School curriculum last fall. Keep up the good work Pat. We need to get the idea to "Make Metric Meaningful" spread wide. Stan Doore Meteorologist (Retired NOAA) Now Science Advisor to the Smithsonian Institution for K-12 Science Courses Development The National Academies ----- Original Message ----- From: "Pat Naughtin" <[EMAIL PROTECTED]> To: "U.S. Metric Association" <[EMAIL PROTECTED]> Sent: Wednesday, June 18, 2003 9:09 PM Subject: [USMA:26134] Re: Ireland, but on topic Dear All, Measuring rainfall in millimetres has the advantage that a millimetre of rain falling on a square metre constitutes one litre of water: 1 m x 1 m x 0.001 m = 0.001 cubic metres = 1 litre If I build a shed 5 metres by 10 metres, I know that its roof area is 50 square metres, and I know that for every millimetre of rain that falls I can collect 50 litres of water in a rainwater tank. I also know that here in Geelong with an average annual rainfall of 550 millimetres, I can collect about 27 500 litres (550 mm x 50 square metres = 27 500 litres) of water from this roof each year. I know very little about snow � we don't have snow in Geelong � but I believe from others that snow turns to water at a ratio of about 10 to 1, that is that 20 millimetres of snow is roughly equivalent to 2 millimetres of water. So back to the roof on my theoretical shed. If 20 millimetres of snow falls on the roof, this is equivalent to 2 millimetres of rainfall, so 100 litres of water will eventually end up in my collecting tank. Maybe meteorologists simply measure rain in millimetres and snow in centimetres as a simple rule of thumb to make the measures approximately equivalent in terms of litres of water. Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is the editor of the free online newsletter, 'Metrication matters'. You can subscribe by sending an email containing the words subscribe Metrication matters to [EMAIL PROTECTED] -- on 2003-06-19 00.17, Terry Simpson at [EMAIL PROTECTED] wrote: >> Paul Trusten wrote: >>> Why not centimeters of rainfall?: >> Norman & Nancy Werling wrote: >> I think one wants millimetres of rainfall and centimetres of snowfall. >> Canada does it that way and I thought that was the normal way of stating >> these measures. > > Ireland and the UK officially measure rain in mm. The UK officially measures > snow in cm (mm may also be used) and I am sure that Ireland is the same. > Unofficially inches are still in use by the public just as Fahrenheit > persists. Government web authors should certainly respond positively to > requests for metric units. > > www.met.ie/climate/rainfall.asp > > www.metoffice.com/construction/pastdata2.html#rands > > >
