點樣決定一隻金屬既density??

1000kg of pure water = 1 cubic metre. Pure water was chosen as the 'base line' for specific gravity and given the value of 1. The specific gravity of all other materials are compared to water as a fraction heavier or lighter density. For example, beryllium has a specific gravity (sg) of 1.84 (1840 kg/cu.m) (see table below)
As specific gravity is just a comparison, it can be applied across any units. The density of pure water is also 62.4 lbs/cu.ft (pounds per cubic foot) and if we know that a sample of alumimium has a sg of 2.5 then we can calculate that its density is 2.5 x 62.4 = 156 lbs/cu.ft.
Note, kg/cu.m divided by 16.02 = lbs/cu.ft

The mass of over 30 different metals and alloys are listed below.
aluminium - melted 2560 - 2640
aluminium bronze (3-10% Al) 7700 - 8700
aluminium foil 2700 -2750
antifriction metal 9130 -10600
beryllium 1840
beryllium copper 8100 - 8250
brass - casting 8400 - 8700
brass - rolled and drawn 8430 - 8730
bronze - lead 7700 - 8700
bronze - phosphorous 8780 - 8920
bronze (8-14% Sn) 7400 - 8900
cast iron 6800 - 7800
cobolt 8746
copper 8930
delta metal 8600
electrum 8400 - 8900
gold 19320
iron 7850
lead 11340
light alloy based on Al 2560 - 2800
light alloy based on Mg 1760 - 1870
magnesium 1738
mercury 13593
molybdenum 10188
monel 8360 - 8840
nickel 8800
nickel silver 8400 - 8900
platinum 21400
plutonium 19800
silver 10490
steel - rolled 7850
steel - stainless 7480 - 8000
tin 7280
titanium 4500
tungsten 19600
uranium 18900
vanadium 5494
white metal 7100
zinc 7135

depends on 隻metal既property, 如corrosive resistance, strength等, price也是其中一個因數, 重要的還有metal的reactivity or extration method

例如corrosive resistance強又inexpensive既copper就用泥做水管