Barometer

 I can't take any credit for this project.  My wonderful husband thought of this idea for a project to do with his cub scout den.  We will be making a homemade barometer.   Before starting here is a website you can go to that explains barometric pressure to kids.  The materials are very simple:

First cut the neck off the balloon and stretch the remainder around the mouth of the jar. Second, cut the straw so the bendy part is removed, you won't need it.  Third, tape the straw to the top of the jar.  Now you can tape the toothpick to the end of the straw if you wish to give you a better point to mark from.  This is what it looks like (I didn't use the toothpick).

Tape a piece of paper to a wall and set the jar in front of it with the long end of the straw facing the paper.  Each day the pressure will change in the jar and the straw will either move up or down.  Have your child mark where the straw is every day that week. Below my son recorded what the weather was like for the day on a separate paper.
When there is a big jump between lines that means the weather is most likely going to change. If you would like to check the accuracy of your chart you can go to this link which has a graph of the barometric pressure in the Fort Wayne, IN  area.  Spring is coming people!