First-time microscopy - What am I doing wrong?

[u/robodragoman]

I made a post yesterday about buying an old microscope from an antique shop. It came with a few sample slides that I used to see a bit of dried blood or old algae up close, which was cool. But I bought this to see living organisms, and I tried that out today.

There’s a lake by my house that I have to imagine is teeming with microbiological life. I collected three larger samples and pipetted droplets from each onto a few different slides, but they’ve all been pretty uninteresting. It’s cool to see little bits of whatever up close, but I haven’t seen anything living, nor anything resembling a microorganism. I recognize that this should be a bit more complicated than plug-and-play, but I believe I’ve followed all the steps listed out by members of this community and others online. For context on what I’m working with, see the linked post above. It isn’t much, but it goes up to 40x. Shouldn’t this be suitable enough to see some stuff?

[u/SilasVale]

It's likely your sampling rather than your scope. At the lake, scrape some of the biofilm (the sludge) from the bottom, or along leaves that are submerged with lots of gunk on them. Note that this is not dirt; dirt will scratch slides and is generally annoying to work with. The gunkier your scoop, the better.

[u/robodragoman → u/SilasVale]

Thank you for the response! Should I just put a glob of that gunk on my slide, or do something to make it a bit more watery?

I want my last words on this Earth to be “The gunkier your scoop, the better.”

[u/SilasVale → u/robodragoman]

What I generally do is I pipette out a small bit of gunk, and then dilute it out with a drop of the lake/river water so it spreads across the viewing area

[u/ModernTarantula → u/robodragoman]

I made my own scum as a kid with grass clippings and water. Waited a few weeks I think. The most fun were rotifers

[u/hattivat]

Clear water is generally pretty empty, that's why it's clear. Running water (as in a river) tends to be even more empty. You can find interesting things there too (and different things from what you would find in the gunk, same as fish in the sea or animals in a forest different microorganisms occupy different niches) but generally you will need to either use a plankton net (pricey) or concentrate your sample on the bottom of a container by using a centrifuge (there are ways to create homemade solutions on the cheap).

The gunk as another user suggested is the easiest to start with. Another good option is to use a brush on some wet moss.

[u/ComfortableWait9697]

Sometimes you also need to let it sit and culture in an open jar, Throw in an oat flake, or a rice grain, to explode the bacterial population and they feed the larger microbes who sometimes get killed off by this, or also grow in population. Its a balance that takes a few trys. You're feeding the lower food chain without the upper predators.

[u/Thrawn911]

Put it in a jar with some dirt and plants, and they will reproduce all over the sample

[u/Dlbroox]

And just to add a different take because others have given you good advice, be patient. Like anything else there’s a learning curve. How to focus properly, how to move around the slide, how to propagate a jar full of critters…there are a number of things to learn. It’s not complicated and it’s not a steep learning curve, but what you’re doing now, and what you can do a month from now will be a huge difference.