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Re: Water Quality B/C
Posted: March 27th, 2012, 8:47 am
by silentsage
ptkid wrote:lolliexdd wrote:I hope this hasn't been answered yet..
We've been having problems building a salinometer like the one they recommended we make, with a straw and clay. Every day that we test any of our salinometers (we've used 3 types of clay already) in tap water, they all float to a different line than the day before. We've even used deionized water instead of tap water to calibrate it, but we still have the same problem. Do any of you know how to fix this?
Okay, so when I tried making that one it just doesn't work. The soinc.org people are just wrong. A simple straw and clay model cannot be that accurate and can easily break. You need to think more sophisticated like how you can make it more accurate. Experiment to get a good salinometer.
And they basically are the same (deionized and distilled water).
I agree, the soinc one is innacurate, but you can firm the clay by lightly coating it in superglue. I've tried to find how to build and electronic one (they are legal), but no luck, anyone else?
Re: Water Quality B/C
Posted: March 27th, 2012, 1:33 pm
by ptkid
silentsage wrote:ptkid wrote:lolliexdd wrote:I hope this hasn't been answered yet..
We've been having problems building a salinometer like the one they recommended we make, with a straw and clay. Every day that we test any of our salinometers (we've used 3 types of clay already) in tap water, they all float to a different line than the day before. We've even used deionized water instead of tap water to calibrate it, but we still have the same problem. Do any of you know how to fix this?
Okay, so when I tried making that one it just doesn't work. The soinc.org people are just wrong. A simple straw and clay model cannot be that accurate and can easily break. You need to think more sophisticated like how you can make it more accurate. Experiment to get a good salinometer.
And they basically are the same (deionized and distilled water).
I agree, the soinc one is innacurate, but you can firm the clay by lightly coating it in superglue. I've tried to find how to build and electronic one (they are legal), but no luck, anyone else?
same. I had no luck. I found out what I was doing was totally wrong so I just made the straw one more sophisticated.
Re: Water Quality B/C
Posted: March 27th, 2012, 7:14 pm
by rtunnel97
I made one a step up from the simple clay and straw, but still it isn't that accurate, i just know it
Re: Water Quality B/C
Posted: March 28th, 2012, 1:54 pm
by cngu23
rtunnel97 wrote:I made one a step up from the simple clay and straw, but still it isn't that accurate, i just know it
Since you get the point for measuring to the nearest percent, should line spacings of around 2.5% be enough for a rough estimate?
Re: Water Quality B/C
Posted: March 28th, 2012, 3:22 pm
by 2win
cngu23 wrote:rtunnel97 wrote:I made one a step up from the simple clay and straw, but still it isn't that accurate, i just know it
Since you get the point for measuring to the nearest percent, should line spacings of around 2.5% be enough for a rough estimate?
I thought I depended on the proctor, but I think that's good enough, since some people are doing 3% or more. 1% is a butt to mark off...
Re: Water Quality B/C
Posted: March 29th, 2012, 4:17 pm
by PacificGoldenPlover
Really? For our salinometer it was fairly easy (the entire range was about 1.5 inches)
Re: Water Quality B/C
Posted: March 30th, 2012, 2:08 pm
by cngu23
PacificGoldenPlover wrote:Really? For our salinometer it was fairly easy (the entire range was about 1.5 inches)
Couldn't get something wide enough to create a large enough different spacing, so I marked it each 2.5%. Spacings are 3mm apart, so its about 1mm per percent concentration. Not the best, but for a maximum of 5% of the competition result, I feel like it would be better to spend more time studying for the written section.
Re: Water Quality B/C
Posted: March 30th, 2012, 7:15 pm
by PacificGoldenPlover
Is it against the spirit of the rules to bring in multiple salinometers?
Re: Water Quality B/C
Posted: March 30th, 2012, 8:07 pm
by cngu23
PacificGoldenPlover wrote:Is it against the spirit of the rules to bring in multiple salinometers?
Since my salinometers are not that accurate, and marked 2.5%, I am using 2 salinometers to confirm my measurements.
Re: Water Quality B/C
Posted: April 1st, 2012, 5:07 pm
by silentsage
cngu23 wrote:PacificGoldenPlover wrote:Is it against the spirit of the rules to bring in multiple salinometers?
Since my salinometers are not that accurate, and marked 2.5%, I am using 2 salinometers to confirm my measurements.
I don't know anything about multiple salinometers, but I made solutions for every even % and filled in the odds. Does anyone think that proctors are scared to make a solution below 3% or above 8%? I've never encountered any higher.