Entropy continued

[JohnRoberts]

It must be the the fancy freeze resistant rain gauge that is off. The other one, being cheap, can't afford to be wrong! ; )

Today the premium freeze resistant gauge is measuring an inch more rain (4 1/2" vs 3 1/2") than the simple plastic gauge. I am inclined to believe the higher amount. The two gauges are located only inches apart.

I will continue watching this. The only rational theory I can come up with is that cheap gauge when angled (tilting back to be easier to read) presents a smaller opening to the sky and rainfall.

JR

 

[DarkSky]

Today the premium freeze resistant gauge is measuring an inch more rain (4 1/2" vs 3 1/2") than the simple plastic gauge. I am inclined to believe the higher amount. The two gauges are located only inches apart.

I will continue watching this. The only rational theory I can come up with is that cheap gauge when angled (tilting back to be easier to read) presents a smaller opening to the sky and rainfall.

JR

It would have to be tilted to a significant angle to cause the aperture presented to the sky to be reduced sufficiently to account for the 29% greater collection in the freeze resistant gauge.

However, if there was steady and strong wind such that the rain was not falling vertically but arriving at the gauges at an angle that happened to be oblique to the tilt of the plastic gauge, that might be enough to account for it. Especially if the other gauge was also tilted, but *toward* the wind...

 

[JohnRoberts]

I am suspicious about tilt explaining it all, but there is a significant discrepancy.

The cheap rain gauge is cheap enough that I could buy a second one and experiment further. Not sure how much I care.

[edit- In the interest of science I just ordered a second identical rain gauge so I can do some direct a/b comparisons. /edit]

JR

 

[MicMaven]

I am suspicious about tilt explaining it all, but there is a significant discrepancy.

Q> Have you checked each gauge with an independent measurement? I would get a known-good graduated cylinder (i.e., small measuring cup) and pour 3-4 oz from that into each gauge and see if that agrees. One or both may be inherently off the mark.

I could buy a second one and experiment further. Not sure how much I care.

!!> Whoa, there pardner. It is too late to pretend you do not really care. You have reach Obsession Level 2 on this one! (Not that there is anything wrong with that, but you got us hooked right along with you, and I am intently curious as to how it turns out !!) You cannot quit now, old man!!!

JHR

 

[cyrano]

You might want to read the Wikipedia page about rain gauges:

https://en.wikipedia.org/wiki/Rain_gauge
Your gauge isn't "standard" and as such, will show a significant error.

It's too small of a diameter (8" standard).
Maybe it's too close to trees, a building...

I think you expect too much of these simple gauges?

 

[JohnRoberts]

You might want to read the Wikipedia page about rain gauges:

https://en.wikipedia.org/wiki/Rain_gauge

in fact no I do not... you are not the first or only forum member here with search capability.

Your gauge isn't "standard" and as such, will show a significant error.

+/- ?

It's too small of a diameter (8" standard).
Maybe it's too close to trees, a building...

surely

I think you expect too much of these simple gauges?

I am mainly trying to understand how two merchantable consumer rain gauges can measure that much of a difference when side by side.

After I perform my tilt experiments with two identical rain gauges I can confirm or rule out my thesis that tilt angle reduces the effective aperture.

I am curious but absolute accuracy does not really matter to me.

JR

 

[cyrano]

Hopeless...

While you're at it, you might want to reinvent the wheel. Is this typical for conservative puritans?

 

[JohnRoberts]

Hopeless...

While you're at it, you might want to reinvent the wheel. Is this typical for conservative puritans?

"conservative puritans" Thats a new one...I have never been called that before.

I hope name calling makes you feel better because it is not very persuasive or engaging.

JR

 

[Youngwhisk]

I am mainly trying to understand how two merchantable consumer rain gauges can measure that much of a difference when side by side.

JR

Because rain does not fall uniformly even in small areas.

 

[JohnRoberts]

Because rain does not fall uniformly even in small areas.

I'll see what 3 rain gauges in close proximity reveals.

JR

 

[DarkSky]

Because rain does not fall uniformly even in small areas.

Hence the recommended ≥8" diameter. Presumably even 8" is a compromise - a point where inconsistencies are reduced but not eliminated (while, on the other hand, still not being unacceptably obtrusive in most situations).

 

[JohnRoberts]

Searching consumer rain gauges I only found one with an 8" aperture and it was like $60 (too much for me... I'm cheap!). However this discussion has me introducing another experimental data point. I have placed a 9" diameter plastic pail in my yard near my array of rain gauges.

The 9" pail looks like it will make an attractive residence for mosquitos, but I will engage it long enough to do a comparison.

JR

 

[MicMaven]

Q> Have you checked each gauge with an independent measurement? I would get a known-good graduated cylinder (i.e., small measuring cup) and pour 3-4 oz from that into each gauge and see if that agrees. One or both may be inherently off the mark.

So, what did you discover? Did you even verify whether the two gauges have equivalent scales printed on them? Pour 4 oz water from a graudated cylinder into each gauge. If both gauges do not indicate the same level, you have at least discovered part of the story. If they agree, you will rule out a potential variance. I would do this before performing any other test to determine whether or not both guages are marked with equal scales. If they agree, you will rule out this obvious possibility.

Repeat Serving Suggestion: You have noting to lose setting a large empty soup or tomato sauce can near your rain gauges to determine how a vessel with a larger opening compares. A 20 oz can is a good size for this purpose. This low cost option may indicate which gauge is correct, without adversely affecting any other experiment.

So far, this is not a very scientifically rigorous investigation, which is OK, but It may be time to get serious. Perhaps, instead of acquiring a second example of either gauge, you might acquire a higher quality gauge from a reputable source/manufacturer and see how it compares. A second example of either gauge you already have should merely replicate your previous experience. Einstein addressed the situation saying, "The definition of insanity is doing the same thing over and over and expecting different results."

Just MY take - nothing too serious here, just having fun looking over your shoulder. JHR

 

[JohnRoberts]

So, what did you discover? Did you even verify whether the two gauges have equivalent scales printed on them? Pour 4 oz water from a graudated cylinder into each gauge. If both gauges do not indicate the same level, you have at least discovered part of the story. If they agree, you will rule out a potential variance. I would do this before performing any other test to determine whether or not both guages are marked with equal scales. If they agree, you will rule out this obvious possibility.

rain is forecast for tonight so I will get some more data by tomorrow...

Repeat Serving Suggestion: You have noting to lose setting a large empty soup or tomato sauce can near your rain gauges to determine how a vessel with a larger opening compares. A 20 oz can is a good size for this purpose. This low cost option may indicate which gauge is correct, without adversely affecting any other experiment.

how about a 9" diameter plastic pail? If the real deal gauges use 8", 9" should be even better.

So far, this is not a very scientifically rigorous investigation, which is OK, but It may be time to get serious. Perhaps, instead of acquiring a second example of either gauge,

my reason for buying a second cheap rain gauge so I can determine if the angle of tilt makes an obvious difference.

you might acquire a higher quality gauge from a reputable source/manufacturer and see how it compares.

nah... the only 8" diameter gauge I found was like $60 which way exceeds my interest in this pursuit.

A second example of either gauge you already have should merely replicate your previous experience. Einstein addressed the situation saying, "The definition of insanity is doing the same thing over and over and expecting different results."

Perhaps I haven't been very clear. I am not going to put two identical cheap rain gauges out with the exact same tilt angle. One will be strictly vertical, and the second one (which has not arrived yet, will be tilted back maybe 30').

Just MY take - nothing too serious here, just having fun looking over your shoulder. JHR

Tomorrows data will consist of the 9" diameter plastic pail, my freeze proof fancy copper rain gauge, and one cheap plastic one standing vertically... The odds of all three being in complete agreement are slim...

JR

 

[MicMaven]

Roger - I appreciate the clarification. As my favorite Army Drill Instructor used to say, "Drive on soldier." JHR

 

[JohnRoberts]

OK the results from last nights rain are in:
9" pail 1" rain.
Copper freeze proof gauge 1"
Cheap plastic gauge 3/4"

I have no theory to explain the -25% error, but trust the pail's 1" reading. Next week I will have a second cheap plastic rain gauge to add to my menagerie.

JR

PS: I didn't have a favorite drill sergeant....

 

[MicMaven]

Great news. I also trust the 1" result.

And yet, PULEEEEEZE, humor me. Pour X oz into one of the gauges, and then pour that same amount into the other, and see if they both register the same level. That may tell you all you need to know, especially now that you have independent confirmation from the big pail which I agree is close enough to the technical standard size to count. I seriously wonder why you do not do this. Am I missing something?​

I pose this solely as a serious scientific question, and NOT as a pest, because that would be my initial line of "course" examination. (yep, pun intended) JHR


P.S. - THIS is my favorite Drill Sgt Ruff -- yep, that really is his name - and he was a big guy who lived up to his name. I admired him 'cause he was all you could expect, and was a decent bloke with a sense of humor. He made my whole summer at Ft Knox when he told me he deeply respected ME, which felt pretty darned good after being kicked around all summer. JHR

 

[JohnRoberts]

Great news. I also trust the 1" result.

And yet, PULEEEEEZE, humor me. Pour X oz into one of the gauges, and then pour that same amount into the other, and see if they both register the same level. That may tell you all you need to know, especially now that you have independent confirmation from the big pail which I agree is close enough to the technical standard size to count. I seriously wonder why you do not do this. Am I missing something?​

The different rain gauges have different cross sectional areas so will hold different amounts of rain water for the same reading height.

I pose this solely as a serious scientific question, and NOT as a pest, because that would be my initial line of "course" examination. (yep, pun intended) JHR


P.S. - THIS is my favorite Drill Sgt Ruff -- yep, that really is his name - and he was a big guy who lived up to his name. I admired him 'cause he was all you could expect, and was a decent bloke with a sense of humor. He made my whole summer at Ft Knox when he told me he deeply respected ME, which felt pretty darned good after being kicked around all summer. JHR



View attachment 121303

The basic training drill sergeants at Ft Dix were not that friendly.... But we only had to tolerate each other for several weeks.

[edit: another thought

The copper freeze proof rain gauge sits higher up in the air than the cheap plastic gauge, so it is possible that the higher copper gauge could shade rain off the lower plastic gauge in some wind direction configurations. I will also space them further apart for ongoing testing. This photo does not show the height in proper perspective. /edit]




JR

 

[cyrano]

The different rain gauges have different cross sectional areas so will hold different amounts of rain water for the same reading height.

Finally...

 

[JohnRoberts]

My new GFCI outlets and replacement cutters for my Flowbee haircutter arrived today. I have already replaced the cutters and my Flowbee is now cutting like new.

Like a watched pot never boiling, my dodgy GFCI outlet is still working, and even survived a brief power interruption a few days ago. I heard the percussive report of a high voltage fuse blowing somewhere nearby (probably from an errant tree branch) and my lights blinked off briefly causing multiple gadgets to reset or lose their digital minds. It wasn't my local fuse but close enough to dip my power momentarily.

I may wait for it to fail again, or at least until warmer weather. The suspect outlet is in my unheated laundry room.

JR