Today I was looking through my collection of art/office supplies of the pen, pencil and marker variety. Many I purchased or were gifts; but some [del]possibly junk[/del] were given to me over the years when someone was cleaning out the attic or basement of a parent. Usually the giver said, “Oh CT you draw you could use these right?”
I have a large zip lock bag of mechanical pencils labeled “mark sense lead.”
After googling I understand what it is; but is there anything interesting I can do with them besides drawing? It is very soft lead.
If it’s labelled ‘Mark Sense’ it probably has an electrically conductive lead that can be picked up with a special reader. There are optical Mark Sense readers also, but they can be used with a good old number 2 pencil.
ETA: I see you already figured that out. I suppose it would be interesting to see what happens when you run some current through it. Regular pencil lead will incandesce with just a few volts at pretty low current. Not sure what a more conductive version would do, except it probably has a high wax content that would catch fire.
Might want to rethink the water hose/electricity thing.:eek:
Just use low amperage/voltage current (i.e. 1.5v. batt’y) and lessen the danger. The “lead” in lead pencils is mostly graphite (though I’m not familiar with the mark sense formula) and graphite is quite conductive. What you basically have is skinny motor brushes for a universal AC/DC motor.
Break the lead into small pieces and put it in a small container lined with foil - something about the size of a film canister. You want at least a half-inch layer of pieces of the lead.
Attach a wire to foil lining. Set another wire in a piece of modelling clay or some such, so that it dangles into the pieces of pencil lead, but does not touch the foil lining the container.
When my youngest daughter was in the 6th grade (back in the late 90s), her Science Fair project involved the electrical conductivity of different pencil hardness attributes.
We took a range of pencils, from 2B through 5B, and then the F and H, and then from 2H to 5H. Her hypothesis was that the softer the pencil, the more it would conduct electricity. (Specifically, when testing it with a multimeter, the resistance of the “leads” (rhymes with “beds”) would go up or down depending on the hardness.)
We tested in two ways. First, she got rough measurements using simple scratch tests by coloring in a box 1-inch by 1-inch with each type of pencil and then putting the multimeter leads (rhymes with “reeds”) in opposite corners. Then, we cut off the ends of each pencil and sharpened them so that each pencil was the same length and had the same amount of graphite showing from each end. Then we put the multimeter leads to the leads and measured the resistance.
IIRC, I think she proved her hypothesis, although the “sweet spot” was around the regular “#2 pencil” threshold. The harder pencils definitely had more resistance as they got harder, but not all the softer pencils had less resistance as they got softer.
Sure. I just couldn’t think of a new-fangled equivalent. What do youngsters use nowadays for storing their spare gramaphone needles and corset buttons?
