on 4/19/2002 12:16 AM, Joseph B. Reid at [EMAIL PROTECTED] wrote: > "4.2 The multiple can usually be chosen so that the numerical values will > be between 0.1 and 1000."
Why is the word "usually" used in the above. The truth of the matter is that the multiple ALWAYS* can be chosen so the value is between 0.1 and 1000. Sometimes it is not convenient to do so but it is always possible*. A low dose aspirin tablet contains 0.000 081 kg of aspirin. That can be written in any of the following ways (using only prefixes representing powers of ten that are multiples of 3): 81 000 000 pg (picograms) 81 000 ug (micrograms) 81 mg (milligrams) 0.081 g (grams) 0.000 081 kg (kilograms) 0.000 000 081 Mg (megagrams) etc. Clearly, by stepping up or down through the list of SI prefixes* one ALWAYS finds at least one prefix that gives a numeric value between 0.1 and 1000. One merely has to look down the list and pick the one that is between 0.1 and 1000. Sometimes, as for example 250 000 metres, it can be written two ways and be within the range of 0.1 to 1000; namely: 250 km or 0.25 Mm Regards, Bill Hooper college physics teacher (retired), USA (Florida) *OK, yes! There is an exception. If the value is so enormously large or so exraordinarily tiny that even ten to the 24th power is not big enough or ten to the negative 24 is not small enough. But how many practical, everyday things do you know that are bigger than 10^24 or smaller than 10^-24 metres or grams or whatever? +-+-+-+-+-+-+-+-+-+-+-+ Do It Easy, Do It Metric! +-+-+-+-+-+-+-+-+-+-+-+
