Weigh the item on a very sensitive weighing machine (down to 0.001g is recommended).
Then weigh it again, but this time suspended in water - that's what the specific gravity kit is for.
Now find a calculator and do a simple calculation.
Pros and cons
Pros: you can test very valuable items such as rare coins which must not be marked in any way. You can also test a large variety of materials including metals and gemstones.
Cons: it's time-consuming, setting up the equipment takes five minutes; after that, each test takes five minutes. And you need to do some (albeit simple) arithmetic and look up a chart. None of this is difficult but it is time-consuming.
PLEASE NOTE, THE WEIGHING MACHINE IS NOT INCLUDED,
YOU WILL NEED ONE THAT WEIGHS DOWN TO 0.001g.
Is it the right size?
Will the attachment fit the scale?
The height from the top of the base to the circle that holds the beaker is 140mm. You can make it as lower, but not higher, so check that the platform of your scale is not too high off the table.
You will also need to slide the base underneath the scale. Ideally, this will require a gap under the scale. The base is 2mm thick. Alternatively, if the scale is very small, it can stand on top of the base, the base measures 100mm X 65mm
The distance from the upright (pole) to the middle of the flask (which should line up with the middle of the weighing platform) is 100mm. You can use a scale requiring a shorter distance but not a longer distance.
What is the largest-size item that can be tested?
The diameter of the platform on which you place the sample is 25mm and the beaker gives you a height of about 45mm.
In practice, an item this tall and thin would fall off the platform; in practise, the largest size would be the equivalent of a stack of 4 or 5 one-pound coins.
See an illustrated guide: click here.
QUESTIONS & ANSWERS
Have a Question?
Be the first to ask a question about this.