I was checking out the book Mondo Magnets… by Fred Jeffers on Amazon. This book can be purchased used for a very reasonable price – I bought a different book for $.01, that’s one cent U.S. I clicked on the “Search Inside” and read about an easy way to separate iron powder from garden dirt or beach sand. I think this will interest a lot of experimenters because they can use this iron powder to make cores for coils. The powder is mixed with a binder, such as glue or epoxy, and formed into the shape of the core. But it may take a bit of effort to separate enough powder to make the cores for a project. so I thought I would show one of the pictures (it’s “fair use”) of how it could be done.
There are many cool experiments in this book. I have been disassembling hard disk drives (the data must be obliterated – see Note) and I’ve retrieved several of the magnets that are used to drive the heads. They are so powerful that they can snap together and pinch your finger and draw blood. Ouch! I’m hoping I can put some of these to good use, because my fridge and desk at work are being covered with them. And I’ve already given a couple dozen to the Physics Dept.
BTW, did you know that iron is fourth most abundant element on earth? No wonder dirt has it!
Another interesting fact about iron. Iron is made by the stars, as are the other heavier elements. Why is your blood red? Because it has hemoglobin. The hemoglobin is red because it has iron in it. That’s why we are all made from stardust.
Note: We were required to, and have been using a program called DBAN to ‘nuke’ the disk drives. This is a program that uses Linux for the OS and runs from a floppy, and back in the days of 10GB hard disks, we could put the floppy in, turn on the PC, and the disk would boot, and immediately start overwriting the hard disk multiple times with a pattern, making it impossible to recover any data from it. As a result, it is thorough but slow, and would take a few hours for a 10GB disk. When disks got to 40GB, it took 9 hours to wipe the hard disk – the limiting factor is the speed of the hard disk. Nowadays hard disks have far exceeded that size, and it’s not practical to run it overnight or for a day or more when we have dozens of PCs taken out of service. We have Dell desktop PCs and it takes only a minute to pop it open, unplug the hard drive and snap it out of the PC and put it in a pile with the others, so that’s what we do. I’ve been disassembling the smaller 10GB or so disks and collecting the magnets on the sides of a file cabinet and desk.