Society, Politics & Law
Seismograph
...base to put it all onto (wood is easy to use) A pole to hang the pen and weight from A rod that hangs from the pole and is free to swing sideways A pen to attach to the rod A heavy weight to attach to the rod (eg a brick) Strong wire, rope or twine (that doesn’t stretch too much) Some way of moving paper at a steady speed (eg round bits of paper stuck to the hand of an...