First, the specific operation method
1. First, weigh the gold and silver jewelry on a high-precision electronic scale (accuracy 0.0 1g) and record its weight;
2. Cut off 1/2 with a plastic bottle filled with purified water, then pour a proper amount of purified water, weigh it on an electronic scale and record the weight; Plastic bottles filled with pure water continue to be placed on the electronic scale.
3. Tie the gold and silver jewelry to be identified with a thin thread (the thinner the better), hold one end of the thin thread with one hand, and immerse the jewelry in a plastic bottle filled with pure water on the electronic scale. Be careful not to let the jewelry sink, not to let the jewelry out of the water, and not to touch the inner wall of the plastic bottle. At this point, record the displayed weight.
Second, the calculation
According to the above operation method, three groups of data are obtained: the first group is the weight of jewelry, the second group is the weight of plastic bottles filled with pure water, and the third group is the weight of plastic bottles submerged in jewelry.
Suppose 1: What we need to identify is silver jewelry. The weight of jewelry is 105g, the weight of plastic bottle filled with purified water is 200g, and the weight of plastic bottle soaked in jewelry is 2 10g.
2 10g-200g = 10g (the increased weight of plastic bottles after soaking in jewelry). According to Archimedes' principle that "an object immersed in a still liquid is subjected to buoyancy, and its volume is equal to the weight of the liquid displaced by the object", the added weight of plastic bottles immersed in jewelry is the volume of jewelry, which is 10 cubic centimeter, that is, 65438+.
We know that the density of pure silver 9999 is X 10.5/cm3, the weight of silver ornaments is 105g, and the volume is 10cm, that is,10cm x10g/cm3 =100g.
Hypothesis 2: What we need to identify is gold jewelry. The weight of jewelry is 19.3g, the weight of plastic bottle filled with purified water is 200g, and the weight of plastic bottle soaked in jewelry is 201g..
20 1 g -200 g = 1 g (the increased weight of plastic bottles after soaking in jewelry), and the increased weight of plastic bottles after soaking in jewelry is the volume of jewelry, that is, 1 cm3, that is, the weight of 1 g purified water.
We know that the density of pure gold 9999 is 19.3g/cm3, the weight of gold jewelry is 19.3g, and the volume is 1cm3, that is,1cm3 x19.3g/cm3 =19.3g. ..
According to the above calculation and calculation, if the jewelry density calculated in reverse does not conform to the inherent density of metal, it is either not pure enough or it is fake jewelry at all.