Sciencemadness Discussion Board

Collecting aquatic critters

ElizabethGreene - 10-6-2019 at 14:00

I'm growing some aquatic plants on my desk and I've observed some tiny "things" swimming in the water. They are large enough to see with the naked eye, but I can't make out any distinguishing features. For scale, you could fit at least 4 on the tip of a 0.5 (mm ?) fine tip mechanical pencil lead.

Question: How do I catch some of these for microscopic examination? I tried an eyedropper and they are too fast for me.

DraconicAcid - 10-6-2019 at 14:24

I would guess a few drops of ethanol would slow them down.

CharlieA - 10-6-2019 at 16:31

Microscopists use a drop or so of 1.5% methylcellusolve to slow them down. I might try a drop of (diluted) glycerin, to see if that works. Of course, sacrificing them will slow them to a grinding stop (no pun intended), but would eliminate a lot of fascinating observing.
I recently read a book about Leuwenhoek and his "wee little beasties" that he observed centuries (1700's?) ago; very fascinating reading!

ElizabethGreene - 11-6-2019 at 10:46

Thanks.

nezza - 14-7-2019 at 13:50

Methylcellulose or VERY dilute Nickel salt solutions narcotise protozoa.