The Atmosphere Suddenly Got Acidic

, , , , | Learning | September 2, 2019

(I work in a cancer research facility. For some background to the story, we are not a learning center, but a fully-functioning research building. We do have students, but they are at least in the third or fourth year of college, and some are even working on their thesis. We have a rule: if you have to use the equipment and do not know how, DO NOT touch it and ask for help. This rule is in place to protect the insanely expensive equipment, such as high-resolution microscopes, centrifuges, and cytometers, because if something happens to them, the hourly fee for a qualified technician runs in the hundreds of dollars. This rule applies to every machine, not only the expensive ones.)

Student: “Hi. I need to measure the pH of this solution.”

Me: “No problem. Here is the pH meter to do that. Do you know how to use it?”

Student: “This one is different than the model I know.”

(All pH meters work the same. You know how to use one, you know them all. pH meters have a crystal electrode that you introduce in the solution, and the machine gives you the pH measure automatically. However, you have to clean the electrode before using it to wash away the conservation solution — KCl — and to not contaminate your own solution with it.  I take her answer as she doesn’t know where the Off/On button is, so I turn it on for her and resume my work. The student takes the electrode, pulls it out of the conservation solution, and plunges it into her solution, which is the same color and texture of blue ink.)

Me: “Did you wash the electrode?”

Student: *confused* “Was I supposed to do that?”

Me: “Well… yes. Because if not, you just cross-contaminated your solution. Unless you know for a fact that your solution contains potassium chloride.”

Student: *alarmed* “Oh, no!”

(She proceeds to take the electrode out of her blue solution and plunge it again into the conservation solution, which turns blue immediately and now will have to be disposed of and replaced. I look at her, speechless. Suddenly realizing what she just did, she says:)

Student: “Oh, oh, what a mess I have made! Oh, my! I will have to do the solution again! I will be back to measure the pH later!”

(And without another word, she ran out of the door. Obviously, I had to clean up the pH meter and the counter and replace the conservation solution for a new one. She has not come back yet to measure the pH of her solution.)

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