Experiment 1: 

"Predict the Weather"

The word "barometer" comes from the Greek words baros meaning "weight" and metron meaning "measure."  In this experiment we will learn how a barometer is used to detect changes in air pressure.

You Will Need:

A Saucer

Water

1 Liter Plastic Bottle

Index Card

Tape

Step 1:  Fill the saucer half way with water.

Step 2:  Pour water into your bottle until it is about 3/4 full.

Step 3:  Keeping your thumb over the opening of the bottle, turn the bottle upside down and quickly move the mouth of the bottle into the saucer of water and remove your thumb.

Step 4:  Tape a strip of the index card to the outside of the bottle so that you can read the level of the water in the bottle.

Step 5:  Mark the level of where the water settles on the bottle.  You can then chart any changes in the level.

The Science Fact: 

The water will not pour out of the bottle.  Instead, the water level drops slightly and then comes to a rest.  The water level will move up and down based on how much air pressure is around it.  This is the same for weather barometers.  When a High Pressure front is affecting an area, the barometer readings(in our case the water level) will be high.  If a Low Pressure front is affecting an area, the barometer readings (in our case the water level) will be low.