Originally posted by kbaumen
I grew a blue vitriol crystal. It's about 4x4x2 cm. I also made a bridge circuit with 4 semiconductor diodes, connected it to a 220/24 V transformer and now I have a pulsing DC 24V source. Yay.
Do you ever experiment at home with things that seem interesting to you?
I do a Mr Wizard kind of thing at our local gradeschool, science demo of ordinary household items used for science. One of the things I did, I have a nice oscilloscope and wanted to be able to project the waveform onto a screen so the kids could see it. One of my kids got a projection TV given to him and when it died I took it apart and found a large double lens assembly, poor lens but it turned out I could use it to project the oscilloscope wave image onto a screen, worked like a charm. I used to live in Jerusalem and a genius buddy, since died, RIP, Ray Scudero, polymath and singer songwriter/luthier, and I one summer found an electronics store in Tel Aviv that had bins and bins full of piezo electric devices, the kind used for electronic buzzers and such. They can also be used as a microphone, being two way devices, put a sound waveform in and it makes that sound, hit it with sound and it produces electrical signals, etc., so we experimented with them as electrical pickups for acoustic instruments, guitars, mandolins, fiddles and such, and were quite successful at it.
So I go back to to the US and was asked to do this science talk at our local school and I thought about those pickups and went to the local Burger King and got a bunch of those styrofoam drinking cups and took some of those piezo's and glued them to the bottom of the cup and then to several versions, one a real original that I intend to do an article about, you remember the tin can with a string thing you can hear each other through, I built one of those as a kid. Well it turns out that you can do the same thing with piezo pickups, two styrofoam cups connected with wires and you can hear and talk into the cup and communicate that way but the wires don't have to be tight, can lay loose on the ground. That was one thing I made, I made others with that idea but I will be typing for 10 pages if I go off on those!