Water Quality B/C

[EastStroudsburg13]

If you use the clay-straw option, you need to make sure it's in as thin of a container as possible to get the most spread-out markings. However, when it works, it's pretty accurate, and doesn't require a whole lot of work or tinkering.

[caseyotis]

Or you could always go the electronic option...

Which is...?

If you use the clay-straw option, you need to make sure it's in as thin of a container as possible to get the most spread-out markings. However, when it works, it's pretty accurate, and doesn't require a whole lot of work or tinkering.

So if you put it in, like, a large graduated cylinder-like container, it will read the same as the container they give you? Or do you bring your own container? I don't remember last year all too well. .-.

[ptkid]

Or you could always go the electronic option...

Which is...?

If you use the clay-straw option, you need to make sure it's in as thin of a container as possible to get the most spread-out markings. However, when it works, it's pretty accurate, and doesn't require a whole lot of work or tinkering.

So if you put it in, like, a large graduated cylinder-like container, it will read the same as the container they give you? Or do you bring your own container? I don't remember last year all too well. .-.

It should read the same in any container. @EastStroudsburg13 could you explain this, I don't see why there would be a difference(at least mine works the same in anything)

[EastStroudsburg13]

Okay, so with a thinner container, I think that more water is displaced as it goes up and down, and so the difference between the marks will be greater. You have to put the salt water sample they give you into your salinometer, because it will only be calibrated to that container.

[Skink]

Or you could always go the electronic option...

Which is...?

You build an electronic meter. I assume you build one to detect current and work as a conductivity meter. This is well above both your and my levels, so I strongly suggest you stick to the 'easy' approach. You'd probably need quite a bit of experience building electronics. This isn't baby's first light circuit, after all.

Make good standards, and be careful when calibrating your container. I also can't stress enough that this is not weighed heavily on the test. Do not give up that 5% or whatever it is, but, also, do not burn time on what kind of creative instrument you can build when spending that time learning the content will serve you better in the long run.

[caseyotis]

Or you could always go the electronic option...

Which is...?

You build an electronic meter. I assume you build one to detect current and work as a conductivity meter. This is well above both your and my levels, so I strongly suggest you stick to the 'easy' approach. You'd probably need quite a bit of experience building electronics. This isn't baby's first light circuit, after all.

Make good standards, and be careful when calibrating your container. I also can't stress enough that this is not weighed heavily on the test. Do not give up that 5% or whatever it is, but, also, do not burn time on what kind of creative instrument you can build when spending that time learning the content will serve you better in the long run.

Thank you for this. I know not to focus too much, but I just want it to work. >.> I think we might have got those 5 points taken away because we spent the whole time working on the factual stuff last year. It was kind of embarrassing.

[JTMess]

Or you could always go the electronic option...

Which is...?[/quote]
You build an electronic meter. I assume you build one to detect current and work as a conductivity meter. This is well above both your and my levels, so I strongly suggest you stick to the 'easy' approach. You'd probably need quite a bit of experience building electronics. This isn't baby's first light circuit, after all.

Thank you for this. I know not to focus too much, but I just want it to work. >.> I think we might have got those 5 points taken away because we spent the whole time working on the factual stuff last year. It was kind of embarrassing.[/quote]

We started out with the straw option (before we built an electronic one) and ended up with like +-2% by using a really thin glass straw, allowing a greater distance between the markings on it. Our electronic one does work a lot like this. It uses a voltage divider to measure the voltage drop of the water, uses Ohm's law to find the resistance, converts that to conductivity, and uses an algorithm to compute salinity using temperature and conductivity. The temperature can have a significant effect on salinity if you end up at a very warm or cool room at the competition or if you're testing in a room with abnormal temperature.

[caseyotis]

We started out with the straw option (before we built an electronic one) and ended up with like +-2% by using a really thin glass straw, allowing a greater distance between the markings on it. Our electronic one does work a lot like this. It uses a voltage divider to measure the voltage drop of the water, uses Ohm's law to find the resistance, converts that to conductivity, and uses an algorithm to compute salinity using temperature and conductivity. The temperature can have a significant effect on salinity if you end up at a very warm or cool room at the competition or if you're testing in a room with abnormal temperature.

O_O
I'll just stick with the easy approach...

[fozendog]

For my salinometer I used a pipette and filled it with salt to weigh it down enough. Oh the irony... But to anyone who has done both the straw and pipette method, which one do you think or better?

[caseyotis]

For my salinometer I used a pipette and filled it with salt to weigh it down enough. Oh the irony... But to anyone who has done both the straw and pipette method, which one do you think or better?

That's actually a good idea. How did it stay upright, though? That's the purpose of the clay on the bottom, instead of filling the straw with something and closing both ends. I think. .-.