Talk:Hydrometer

Historical content section needs re-write
The section titled hydrometer used in an actual historical context 1854 contains text copied directly from the book "The Physical Geography of the Sea" (as noted by the contributor) but uses words like "I" and "us", which isn't the appropriate tone to use for an encyclopedic entry. Could someone re-write the section?

Could be heavily pruned if you ask me. I would say most of the information in that section is totally irrelevant. Gamsarah 15:35, 29 October 2006 (UTC)

Weight-Mass?
I'm confused by the use of the word weight in this article, does it mean mass? The article talks of grammes per cubic centimeter, but gramme is a measure of mass not weight. Alun 07:17, 22 February 2006 (UTC)

Electronic densitometer
I reverted this addition because it is rather confusing:
 * A portable, electronic densitometer can determine the density of liquids by comparing the natural frequency of a drawn sample to that of pure water. The instrument compensates for temperature, and displays results in density, specific gravity, API degrees, Brix, % Alcohol, % H2SO4, Baume, Plato, Proof or a user-defined unit.

What is "the natural frequency of a sample compared to pure water"??? What's the difference between specific gravity and density? And the description is missing a rudimentary explanation of how it works - or it might be in the "natural frequency" which is unclear to me. Han-Kwang 18:03, 5 April 2007 (UTC)

Jeroboam Bramblejam writes: Thank you, Han-Kwang, for your careful reading of my contribution~ I will clarify it at my earliest opportunity~ Best wishes, jeroboambramblejam

How to Build one
Maybe you guys (whoever's editing this page) can make instructions to build one. That would really help. I remember when I had to do a project about hydrometers. What a nightmare!

Thanks, Jetster (Jetsterjinx) —Preceding unsigned comment added by 137.132.3.7 (talk) 13:24, 30 October 2007 (UTC)

Aerometer
There's a rather slim and so-so article on aerometer which seems to exactly overlap with hydrometer. Merge? Pdch (talk) 15:00, 19 January 2008 (UTC)


 * I'm inclined to say delete. Googling turns up almost nothing except dictionary sites and pages for some sort of aircraft instrument used to track hours in flight. Mangoe (talk) 13:34, 3 February 2008 (UTC)


 * Merge: the term is used in physics (at least in my undergrad physics lab). Whmice (talk) 09:45, 21 January 2009 (UTC)

Do not merge with 'hydrometer'. Hydrometers are used only with liquids while pycnometers are used with liquids and solids. Hydrometers belong to the buoyancy methods while pycnometers don't —Preceding unsigned comment added by 158.169.9.14 (talk) 10:08, 19 November 2009 (UTC)

oscillating body hydrometer
Googling this as a phrase produces no hits at all; neither does "oscillating hydrometer". Could we have a reference? Mangoe (talk) 15:12, 1 May 2008 (UTC)


 * What is an oscillating hydrometer? What's its purpose? How does it work? Venny85 (talk) 15:29, 1 May 2008 (UTC)


 * If you were referring to this previous paragraph, the editor is mistaken.
 * Another type of hydrometer is the electronic Oscillating Body hydrometer which determines the density of a small sample drawn into a glass tube mounted on an oscillating mechanism. The difference in frequency between the test sample and a reference sample of distilled water is a measure of the density of the sample, which is displayed digitally. This embodiment of the hydrometer facilitates a wide range of features including measurement units conversion, temperature compensation, and calibration compensation.
 * The editor was most likely referring to the Oscillating U-tube method of measuring density. There is no such thing as an "oscillating hydromter". Venny85 (talk) 15:33, 1 May 2008 (UTC)

Jeroboambramblejam (talk) 16:15, 1 May 2008 (UTC) The technical manual for the Mettler-Toledo "Densito 30PX" says: "The instrument uses the oscillating body method." There is no such thing as an "oscillating hydromter"; If you notice a simple typo, just correct it, but please be certain of your spelling... "hydromter" is a misspelling of hydrometer. Moreover, I did not refer to an 'oscillating hydrometer', but rather an 'oscillating body hydrometer'. I would be happy to elaborate on the technology, but I didn't want to interrupt the narrative; I simply wanted to introduce the fact of a newer method and instrument. I can fax the manual to interested parties. I will revert the erasure tomorrow unless a valid objection is raised. Regards, jeroboambramblejam


 * I looked up the instrument you mention. It is not a hydrometer at all, but a density meter which I gather uses the Oscillating U-tube method mentioned above. The ad copy says that it "replaces 4 sets of hydrometers" (my emphasis); it does not say that it is one. Mangoe (talk) 16:25, 1 May 2008 (UTC)


 * I totally agree with Mangoe. The device that jeroboambramblejam mentions uses an oscillating tube that is comprehensively described in Oscillating U-tube, and is not a hydrometer. Since it is not a hydrometer, I don't think it should be mentioned here. However, we can add Oscillating U-tube to the See also list, which i've taken the liberty of adding already. Venny85 (talk) 09:26, 2 May 2008 (UTC)

Jeroboambramblejam (talk) 00:15, 3 May 2008 (UTC) I respect the editors' preference to reserve the term 'hydrometer' for a specific manifestation of a device to measure the density or specific gravity of liquids. Perhaps "An hygrometer is one of several instruments that can be used to measure the density or specific gravity of liquids..." would be an appropriate way of introducing the fact that the hydrometer has modern - and much more accurate and versatile - incarnations. The product I mentioned has a specification of +/- 0.001 g/cm3 and automatic temperature compensation of +/- 0.36 deg F. Best wishes, jeroboambramblejam


 * Frankly, you don't seem to know this instrument more than what was stated in its manual. A hygrometer is used to measure relative humidity. Just because the instrument measures density doesn't make it a hydrometer. And because it gives a digital result doesn't make it a modern hydrometer. If we were to say that any device that measures density is a hydrometer, then a pyncometer would also be a hydrometer. Ships also use their plimsoll lines to estimate the density of the seas they are in, so a ship is also a hydrometer, a crude hydrometer in your context. This instrument has a resolution of 0.000001g/ml and can give reproducibility results of 0.0005g/ml results. It can be calibrated with reagent grade water, n-nonane, n-tridecane, cyclohexane or n-hexadecane. I've not only worked with these instruments, i've also calibrated, set its functioning algorithims, input its temperature conversion tables for various substances and repaired them.


 * My point is that this instrument, know commonly in the industries as DDA, Digital Density Analyzer or DMA, Density meter automatic, is just another method of measuring density out of the many possible ways. Its a novel technique but in no way more modern than the others. Claiming that it is a modern hydrometer is not accurate. The modern hydrometer if I would describe is better than 100 years ago with improvements like an attached thermometer, but the DDA is definitely not a hydrometer and functions in no way on the principle of a hydrometer either. It's another type of density measurement unlike a hydrometer. It would be more appropriate to add your information to Density or to Oscillating U-tube. Venny85 (talk) 03:37, 3 May 2008 (UTC)

Jeroboambramblejam (talk) 17:57, 3 May 2008 (UTC) My bad... I typed "hygrometer" rather than 'hydrometer', both with which I am familiar. Secondly, I have already agreed to the objection that the densitometer is not an hydrometer. However, like the hydrometer, it is an instrument used to determine the density of liquids. I suggest: 1) Add 'Densitometer' to the 'see also' list; the 'Density' and 'Oscillating U-tube' entry headings do not inform the reader that they might link to an alternative, versatile and high precision instrument which is used for the same purpose as hydrometers. 2) Reorganize the rather cryptic 'Oscillating U-tube' entry under 'Densitometer', and add a photo of the hand-held Mettler-Toledo (or similar) product to indicate a portability not suggested by the depicted tabletop model. Also, other densitometer designs that Venny85 mentions ("...just another method of measuring density out of the many possible ways. Its a novel technique but in no way more modern than the others.") would then have a place in the entry. Regards, jeroboambramblejam


 * I support renaming Oscillating U-tube to something more 'proper'. However, Densitometer is also an instrument measuring optical density. I suggest renaming Oscillating U-tube to Digital density meter and have the former page redirect to the latter. However this must go into Oscillating U-tube's talk page before it is moved, so see you there. Pictures of Mettler-Toledo products that are non-copyrighted would be pretty hard to come across. Venny85 (talk) 03:40, 4 May 2008 (UTC)

Jeroboambramblejam (talk) 01:12, 5 May 2008 (UTC) Technical terminology can get complex. We might take a hint from the Mass Spectrometer and call it a "Mass Densitometer" - which would distinguish it from the photographic film 'optical' densitometer, and encompass variations on the U-tube approach. I can take the photo, and a macro that shows the modified U-tube element that the manufacturer calls the "oscillating body" - actually, a triply bent glass tube which forms a tuning fork arrangement of a pair of U-tubes; each U-tube is affixed with a metal element at the outside of its bend, each of which interacts with what appears to be a magnetic head taken straight from a cassette tape recorder.

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Measuring relative density vs specific gravity
A hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. Doesn't a actually hydrometer measure actual density? Most of the scales are defined with respect to a standard density of water, yeah... but it doesn't actually compare the density of the substance being measured with a sample of water; and the readings won't change with temperature based on changes in the density of water in that temperature [only with changes to the actual density of the substance as it expands] except in so far as the hydrometer itself expands. --Random832 (contribs) 01:05, 27 July 2008 (UTC)


 * I read that and wondered the very same thing. A hydrometer is based on the principles of buoyancy. Thus the proportion of the hydrometer floating above the surface has to do with the density of the two fluids (air could be approximated as a vacuum), the density of the hydrometer, the force exerted by gravity. So it could be said that a hydrometer measures the density of a fluid relative to the density of the hydrometer by measuring its buoyancy (proportion above and below the top of the liquid). But, as pointed out, the only aspect incorporating specific gravity with respect to water is the tendency for hydrometers to be graduated as such. So I think it is true, hydrometers measure the relative density but only relative to the density of itself. However it cannot be said they measure specific gravity (disregarding the gradation) since specific gravity is based on the density of a reference of which any given hydrometer is not unless it is designated a reference such as the kilogram mass. It should be worded clearly as to differentiate relative density as used in the principle and in how they are typically graduated. The density of the hydrometer will be slightly temperature dependent. If its enclosed in borosilicate glass, the density should decrease by only 0.1% with a 100°C increase in temperature (as calculated using volumetric coefficient of expansion). I'm surprised this has not been resolved in 10 years. Devon (talk) 05:20, 9 May 2018 (UTC)

Swing-arm hydrometers
How does a swing-arm hydrometer work? --Random832 (contribs) 01:13, 27 July 2008 (UTC)

Potato ripening
I have heard of a device that is quite similar to the hydrometer but measures the density of a sample placed in the bulb. In that application the sample was potatoes and the density depended on the starch content and thus related to ripening and the gastronomic quality. In order for this to work the bulb should be a cage or other device permitting the sample to be immersed in a standard liquid (typically water) and the sample quantity must also be standardised (typically a certain mass of potatoes) and the sample should of course be clean so that the potatoes are first washed. If someone knows more about this device, e.g. its name, please include it or link to that device! —Preceding unsigned comment added by 90.239.105.50 (talk) 21:21, 18 July 2010 (UTC)

Hydrometer scales
Please see Talk:Brix for a discussion about a possible new article for Hydrometer scales. Biscuittin (talk) 09:33, 16 June 2009 (UTC)

Neither areometer nor aerometer
This says the instrument in the diagram is a hydrometer. It has a fixed weight and variable volume of immersion due to the volume of the stem. The historic areometer had a fixed volume and adjusted the weights like balancing a scale. And an aerometer seems to be either an instrument for measuring the density of gases, or a machine for ventilating mines. --Wtshymanski (talk) 13:39, 27 June 2011 (UTC)

Aerometer incorrectly redirects here
"Aerometer" incorrectly redirects here, but I do not know how to fix it. James K. 71.50.19.103 (talk) 07:35, 25 July 2011 (UTC)

Use in Aquariums
I'm surprised that this article does not mention the hydrometer's use in measuring the specific gravity of freshwater or saltwater marine aquariums, especially considering that this is no doubt the most popular home-consumer use for the device. — Preceding unsigned comment added by 76.110.212.12 (talk) 02:00, 18 August 2011 (UTC)

Incorrect References
The first reference is a dead link, the second link is unreliable.

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History section is a mess
The history section is a mess. The only reference to modern history claims (without giving a reference) that the hydrometer appears in the works of Jacques Alexandre César Charles, who was born in 1746, but a London instrument maker, John Clarke, was marketing hydrometers in 1725, when they were in use by the Excise authorities to measure the strengths of spirits, and there is extensive evidece of their use by brewers from the 1770s. Further, under 'saccarometer, it claims that Thomas Thomson invented the saccharometer. As he was only nine years old in 1784 when John Richardson published Statical Estimates of the Materials of Brewing, which introduced the term 'saccharometer', this cannot be correct. Zythophile (talk) 08:46, 6 April 2018 (UTC)