Adam's House (WPVI) -- Here's a fun one - of course, as a meteorologist, I'm a little biased, but this is still a fun project to do with your kids, while learning a little more about the weather and how to make your own forecasts.
WHAT YOU NEED:
Glass mason jar or empty can of beans/tomato sauce
1 Rubber band
Tape and or glue
Pin or paperclip
Piece of paper or large construction paper
Marker or crayon
Make sure the glass jar or empty tin can is clean and dry.
Cut the top off the balloon (the part which you blow into).
Stretch the balloon over the top of the jar and place a rubber band over the lip of the jar to hold the balloon into place.
Take the straw and on one end either take a piece of tape, or better glue, and adhere it to the middle of the balloon. You want at least one third of the straw to hang over the edge.
Then with a pin, or open a paperclip so it is straight, insert it into the end of the straw (not the balloon side). You are welcome to glue this too.
Take a piece of paper and tape it to a wall. Then draw a line where the needle is pointing straight. This is your baseline. Make sure your barometer is on a flat surface and the needle is ALMOST touching the paper, but is NOT touching it. Never move or touch any part of the barometer for a couple weeks.
Every few days, or especially if a big storm passes through, take a look and see if the needle has moved up or down. If it has, mark it and put the date.