各公制单位的名称及代表意义如下表所示:
Table 2-1. Metric Unit Values & Conversion(长度单位)
Unit
|
Symbol
|
Value (decimal)
|
Value (fractional)
|
Value (exponent)
|
Relative Size
|
Kilometer |
km |
1,000m | 1,000m |
103m |
largest |
Meter |
m |
1.0m | 1.0m |
100m |
|
Centimeter |
cm |
0.01m | 1/100m |
10-2m |
|
Millimeter |
mm |
0.001m | 1/1,000m |
10-3m |
|
Micrometer |
mm |
0.000001m | 1/1,000,000m |
10-6m |
|
Nanometer |
nm |
0.000000001m | 1/1,000,000,000m |
10-9m |
smallest |
Table 2-2. Metric Unit Values & Conversion(重量单位)
Unit
|
Symbol
|
Value (decimal)
|
Value (fractional)
|
Value (exponent)
|
Relative Size
|
Kilogram |
kg |
1,000g | 1,000g |
103g |
largest |
Gram |
g |
1.0g | 1.0g |
100g |
|
Milligram |
mg |
0.001g | 1/1,000g |
10-3g |
|
Microgram |
mg |
0.000001g | 1/1,000,000g |
10-6g |
|
Nanogram |
ng |
0.000000001g | 1/1,000,000,000g |
10-9g |
smallest |
Table 2-3. Metric Unit Values & Conversion(体积单位)
Unit
|
Symbol
|
Value (decimal)
|
Value (fractional)
|
Value (exponent)
|
Relative Size
|
Liter |
L |
1.0L | 1.0L |
100L |
largest |
Milliliter |
mL |
0.001L | 1/1,000L |
10-3L |
|
Microliter |
mL |
0.000001L | 1/1,000,000L |
10-6L |
smallest |
同学必须熟练各单位之间的转换,例如:
3.5 cm = 3.5 10-2 m
= 3.5 10-2 106 m m = 3.5 104 m m
转换单位之目的在于避免使用极大或极小之数字。