After that Fred and Barney who were ship painters figured out they could hook up a Brontosaurus up like an air compressor...
Trying to figure out which end of the Brontosaurus was hooked to the air nozzle.
When my younger son was in second grade, I did a presentation on geology (not that I know much). I worked at a university, and the geology tech loaned me one of the polarizing microscopes that allow geologists to study rock structure. What the geologists (actually, their lab techs) do is mount a thin slice of rock on a microscope slide and then slice it even thinner, until it's possible to shine light through it. Turning the slide around on the microscope slide, with polarized light shining through it, will highlight the structure of the rock. It's most impressive, of course, with crystalline rocks like granite. I talked for a couple of minutes about how much there is inside everything we see, and how rocks are made up of crystals (I think I had a transparent crystal of some kind to show them), then the kids lined up to look through the microscope - and then they went back and got in line to look again and again.
You have to find that balance point where you respect the kids' intelligence but show the tools at a level simple enough for their grade level; and relate what you've got in some way to their world. There'll be a few kids who've grown up seeing tools used, because they have parents who work on the house/car/dirigible; they'll probably be easy to communicate with. And then there'll be a lot of them who live in the tool equivalent of those folks who think milk comes from the cooler section of the store in plastic jugs, and meat wrapped in plastic. You may be able to get through to a few of them.
I'd show braces, bits, planes, basic tools like that rather than twybils (just to pick out one of the obscure tools). If you've got a push drill or an eggbeater drill with shielded gears, and if the school is OK with this, I'd have a nice thick pine board set up on the table, or better yet on a kid-height sawhorse where you could let the kids drill holes. I might have an extra M-F shielded-gear eggbeater drill...send me a message if that would be helpful.