How can i make a barometer?

Question

like you know oneof those ones witha balloon in such or whatever

Answer 1

take an empty coffee can. scratch a balloon over the open end of the can, like a drum.  then pluck one brissel from a broom. place it horizontally across the balloon with one end centered on the balloon. Tape in place.  This will act as a needle.  Then find a piece of cardboard that us about an inch taller than the coffee can.  place the cardboard next to the needle and mark the location of the needle.  in a few hours/days compare the location of the needle to the first location.  this will indicate a rise or fall of atmospheric preasure.  If the needle is higher, then the surrounding air (the atmospher) has a lower pressure than the initial reading.  if the needle is lower, then the atmospheric preasure is greater then the initial