Sight glass level concave measurement

[wbtenor]

Yesterday as I calibrated my sight-glass, I filled 2 quarts at a time (largest measuring vessel I had) and at the end, I realized that my false bottom and dip tube weren’t in. I know that I could just drop them in and measure the difference and mark accordingly, but I’ll be calibrating another vessel too and had a question.

When I filled the pot, the sight-glass line was perfectly level. As soon as I drained any volume, I ended up with a concave line which is what I assume I’ll be working with most of the time in my HLT. I know it’s pretty anal and specific, but the difference from the top of the line and the bottom of the bulge is almost 1/16”, so if I’m marking permanently, I’d rather have the marks in the right place. I know as long as I’m consistent with the marking, I should be fine, but I was curious about where the actual liquid level is in the sight-glass: top line, bottom of bulge, somewhere in the middle?

Yes, mostly just a science question, but I’d rather do it right the first (or second) time and stick with it. Thanks for any help!

 

[ClaudiusB]

Yesterday as I calibrated my sight-glass, I filled 2 quarts at a time (largest measuring vessel I had) and at the end, I realized that my false bottom and dip tube weren’t in. I know that I could just drop them in and measure the difference and mark accordingly, but I’ll be calibrating another vessel too and had a question.

When I filled the pot, the sight-glass line was perfectly level. As soon as I drained any volume, I ended up with a concave line which is what I assume I’ll be working with most of the time in my HLT. I know it’s pretty anal and specific, but the difference from the top of the line and the bottom of the bulge is almost 1/16”, so if I’m marking permanently, I’d rather have the marks in the right place. I know as long as I’m consistent with the marking, I should be fine, but I was curious about where the actual liquid level is in the sight-glass: top line, bottom of bulge, somewhere in the middle?

Yes, mostly just a science question, but I’d rather do it right the first (or second) time and stick with it. Thanks for any help!

Here is your answer
http://chemistry.about.com/od/chemistrylabexperiments/qt/meniscus.htm

test
http://chemistry.about.com/od/chemistry-test-questions/tp/Measurement-Test-Questions.htm?nl=1

Cheers,
ClaudiusB

 

[Reno_eNVy]

Yeah, as linked to above, that's the meniscus. You always want to read your levels from the top or bottom of the arc of the meniscus.

 

[wbtenor]

Thank you ClaudiusB! It's been a few years since chemistry. I totally forgot the term "meniscus" or a google search may have proved easier! Cheers!