Society, Politics & Law
Seismograph
...careful when the weight is hanging from the wire, taut wire that breaks suddenly can hurt if it hits you. Sharpen the end of the rod, or have the sharp end of a screw sticking out of the end. Make a dent in the piece of metal to use for the pivot point (by putting the pointed end of the rod in). You don’t want there to be too much friction here, but you want the rod to...