Objective:
To build a barometer and measure the atmospheric pressure. Barometers are typically filled with liquid Mercury. Because liquid Mercury is a very dangerous substance, you will use water for the barometer.

Materials:
One 2-liter pop bottle
One 12-inch ruler, metric scale would be nice
Three (3) rubber bands
deep bowl-flat bottom, wide enough to fit 2 liter pop bottle, deep enough to hold 6-8 inches of water
internet access (or a telephone)

Procedure:

1. Use the rubber bands to attach the ruler to the bottle.
      a. metric side of ruler out preferably
      b. smaller numbers on ruler should be closer to the bottom of the bottle
   
2. Fill the two liter bottle ¾ full of water
   
3. Fill the bowl almost to the top (leave 1.5 - 2.0 inches at top)
   
4. Read through the next few steps carefully before doing them
      a. place your hand firmly over the top of the bottle
      b. turn the bottle upside down (be sure not to let water spill out)
      c. place the bottle, top first, into the water (your hand will get wet)
      d. balance the bottle on the bottom of the bowl
      e. allow the bottle to stand on its own
   
5. Adjust the ruler so that the top of the water within the bottle is at an even mark within the middle of the ruler.
      a. metric will work best
      b. line up top of water in bottle with 5 cm mark or 3 inch mark
      c. place rubber band around the bottle & ruler at the water mark
       picture of close up of ruler on bottle
6. Now we need to "calibrate" the barometer
      a. if internet access is available
          I. follow this link
          II. mark your bottle at the top of the water with the barometric pressure of the closest airport
      b. if internet access is not available
          I. call Matt at the television station (896-5144)
          II. ask me for the barometric pressure value
          III. mark your bottle at the top of the water with the barometric pressure of the closest airport
   
7. Wait 24 hours and repeat step 6.
      a. Mark the bottle at the water level with the new pressure value
      b. Measure the distance between the new mark and the old mark
      c. This will now be your scale
          I. if the water level has changed 1 centimeter and the barometric pressure has changed by 10 millibars then you will know that every centimeter of change on your water level will equal 10 millibars.
8. keep a log of the barometric pressure for the next 2 weeks
      a. print out the barometric pressure log
      b. write in the barometric pressure each day
      c. note the weather conditions each day and the whether the pressure went up        or down since the previous day