Making a Barometer!

Use your scissors to carefully cut the neck off of the balloon.
 

Pull the balloon over the top of the jar, as tight as you can, and secure it with the rubber band. It’s important that no air is able to escape from the jar.
 

Use tape to secure the end of the straw to the balloon, making sure that the very end of the straw is in the centre of the jar.
 

Fold your card stock in half lengthwise and use your ruler to draw lines ½ inch apart, from top to bottom, all along one side of the paper. For reference, you can draw a Sun on the upper area of the lines and some rain drops on the lower area.
 

Stand the paper up and put the jar next to it, the straw should be against the paper and level with the middle area.
 

Put your jar in a place where the temperature doesn’t change much; away from windows and vents. If the air in the jar warms up or cools down, it will affect the readings from your barometer.
 

Observe your barometer whenever you’d like an idea of what the weather will be like that day. High pressure, meaning the straw will move up the scale, means sunny weather. Low pressure, the straw moving down the scale, means rain or a storm is coming.