category:test-limits
category:test-limits


Author Comment Last activity Moderation
warren "OMG this is the best, Scott :-) Hey i'll be in NOLA next friday for a week!  -- ig: @unterbahn | he/him/his On Thu, Jan 30, 2020 at 5:10 PM \&l..." | Read more » about 4 years ago
eustatic "I did this with a Lighter and a Public Lab card, thanks to Stevie. Set the Public Lab card on a tiny fire, put it out, let it smoke up the sensor,..." | Read more » about 4 years ago
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crispinpierce " Hi Stevie, Thanks so much for carrying out these tests. The results seem logical given the particle sizes of the solids you tested (e.g., sugar cr..." | Read more » almost 5 years ago
warren " I'd love to combine this with a microscope activity to look at each of the powders for scale! " | Read more » almost 5 years ago
stevie " Not too long. Maybe 3-5 seconds " | Read more » almost 5 years ago
warren "@warren awards a barnstar to stevie for their awesome contribution! " | Read more » almost 5 years ago
warren "Wow, this is a really great activity! And great video!!! Did the cocoa take a while to clear out and return to green? " | Read more » almost 5 years ago
gretchengehrke "@warren, I thought the sandpaper we used (that was like a polisher) worked well to remove grime on the surface of the copper, which is its purpose...." | Read more » about 6 years ago
warren "And do you have to discard the sandpaper on each use, or can it be used over and over? Thanks! " | Read more » about 6 years ago
warren "Hi, i saw you mentioned: it’s almost more like a polisher regarding the sandpaper -- was that a bad thing? Would you opt for a different grade of..." | Read more » about 6 years ago
warren "Just linking in here to the question where some of us have been looking for different materials and setups to do this test with: https://publiclab..." | Read more » about 6 years ago
warren "Hi, gretchen - the photos are great. Do you have a list of Amazon links and prices you could add -- as a step in getting a prototyping kit together..." | Read more » over 6 years ago
gretchengehrke "Here are before and after photos. We did not expect (and did not observe) any discoloration since we were only putting them out for less than 24 ho..." | Read more » over 6 years ago
gretchengehrke "Here is a picture after sanding one of the little copper strips. The green pad is actually soft sandpaper / polishing paper. " | Read more » over 6 years ago
gretchengehrke "Here is a picture of cutting the copper sheet into strips. " | Read more » over 6 years ago
gretchengehrke "Hi @warren, Thanks for the reminder to add pictures. I have tried inserting photos a few times today, but it keeps crashing the edit (and, seemingl..." | Read more » over 6 years ago
warren "And if there are any photos of these steps, i'd love to help make diagrams to illustrate the process! " | Read more » over 6 years ago
warren "Hi! Do you have photos you can attach for what the copper should look like before/after H2S exposure? Or after any possible false positives? " | Read more » over 6 years ago
zengirl2 "@gretchengehrke OK, ty for the response. Sounds like I need to check manufacturers about the copper tape to see how pure it is. Also, I was thinkin..." | Read more » over 6 years ago
gretchengehrke "Hi @Zengirl2, I'm not sure about the copper strips. Whatever copper is used needs to be fairly pure, and I'm not sure if the copper tape is pure c..." | Read more » over 6 years ago
zengirl2 "@gretchengehrke Do you know if copper tape can be used? I'm considering giving testers out at the Factory Farm Summit mounted on cardboard. Also, s..." | Read more » over 6 years ago
warren "A comment was deleted due to violation of community code of conduct. " | Read more » over 7 years ago
cfastie "Thanks Patrick, The table and graphs are screen captures from Excel. The graphing module in Excel is very powerful in part because it has a huge n..." | Read more » over 7 years ago