Hydrometer question

What are the measuring units on a hyrometer? I know it is measuring specific gravity (density of a substance) but what are the the units it is measuring in, like a thermometer measuring ⁰C? Thanks for the help

Specific gravity is a unit-less number, like Reynold's number, etc. in fluid dynamics. A specific gravity of 1.054 means your liquid is 1.054 times as dense as water.

from what i could find its a ratio of the weight of a volume of liquid, compared to the weight of a volume of a reference liquid (usually water). so its a ratio, not a measurement. if that makes sense. someone smarter may correct me though

is it kg/m 3?

it doesn't matter, you could measure it in kg/m or lb/ft or anything. the ratio will be the same, thats why it doesn't have units

So it is basically a weight to volume ratio to water

OK,I read that a drug test for a job applicant also measures specific gravity.So does marijuahna,or other drugs make your piss more dense,or less dense? also is specific gravity the weight of the liquid,as I have been led to believe on this site? i.e.,a hydrometer measures the fermentable sugars in the wort,thats why you take an OG reading,which tells you the gravity(again,how many fermentables are in the brew)and a FG reading,which tells you if the fermentables are done fermenting or not,i.e. how much sugar is left,and liquid with fermentables in it weighs more than fermented liquid,(also used to estimate the ABV.),but my question is,How does a drug screen measure specific gravity?are there solids in the urine sample that make it weigh more? hell,for that matter,could I use my hydrometer to give myself a drug test? Just Busch talkin here. Busch Ice.haha.

If that is true,couldnt you use a scale to weigh the liquid before and after fermenting and somehow come up with the same end result readings?

Wouldn't your result be dependent on the accuracy of a volume measurement? I would imagine measuring 5 gallons accurately enough to mimic a hydrometer would be tough/not worth it. With just original/final weights of the whole brew (no volume) you could probably figure out how much was actually fermented, but not the actual OG/FG relative to water.

The shape of the hydrometer is what makes it so accurate, accentuating the difference in buoyancy by being shaped like a buoy instead of floating like a canoe. Graduated cylinders do the same thing for increasing precision for volume measurements being tall/skinny. More practical than weighing the whole batch would be taking a small sample into a graduated cylinder for a precise volume/weight measurement (which the hydrometer is essentially doing/combining for you). Imagine a 5 gal graduated cylinder and a scale to weight it!

Aaron

re: Taterbug

I believe drug tests use more sophisticated techniques to actually measure and identify drugs (various forms of spectroscopy and such). They test temperature and specific gravity of the sample to help confirm that it is in fact fresh, unaltered and undiluted urine. If these are outside normal ranges, you are suspect of cheating the test (adding something, diluting your specimen, etc).

Measuring the SG of your urine would help you confirm that it is urine

Aaron

iiBREW said:

So it is basically a weight to volume ratio to water

Click to expand...

yes