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DIY Altimeter

Fliers, skydivers and mountain climbers make use of the altimeter to track their height above sea level. The atmosphere, a layer of air above the earth, exerts pressure on everything on the planet. As we climb or fly above the ground, the atmosphere thins and the air pressure is reduced. A barometer measures air pressure in a fixed location, indicating the existence of weather patterns in that one area. Since the altimeter moves with the climber or pilot, its readings are altitude rather than weather dependent. Building and calibrating an altimeter is a fun and easy project you can do yourself.

Things You'll Need

Clear plastic tubing --10 feet long, 1/4 inch in diameter
Wooden board -- 1 foot wide by 2 feet long
Electric drill
Wire
Clamp
Water
Food coloring
Measuring cup
High-rise building
Elevator
Building plans
Permanent marker

Instructions

Building the Altimeter
- 1
  Drill two small holes 1/4 inch apart, 3 inches from the long side and 6 inches from the top of your 1-foot-wide board. Measure 1 inch directly across from the first two holes and drill two more.
- 2
  Thread a piece of wire through each set of holes so that you have four wire ends protruding at the back of the board. Slide your 10-foot piece of 1/4-inch clear plastic tubing under the first wire loop at the front of the board and turn it up and under the second loop to form a U. Each side of the U should be about a foot long.
- 3
  Twist and tighten the wire ends at the back of the board to hold the tubing in place. Coil the extra tubing that was inserted under the second wire loop and secure the open end with your clamp. Leave the short end open.
- 4
  Add four drops of food coloring to two cups of water in your measuring cup. Stir. Hold the board upright and take the clamp off the coiled end. Pour the colored water into the short end until the U tube is half filled. Replace the clamp on the coiled end.
Calibrating the Altimeter
- 5
  Select a high-rise building that has easily accessible plans indicating the structure's height. Mark the level of liquid in the coil at ground level, using your marker.
- 6
  Ride the elevator halfway up the building. Mark the level of liquid in the coil once more.
- 7
  Proceed to the top of the building. Mark the level of liquid in the coil at this final height. You should have roughly double the change in the water level at the top as the level recorded half way up the building. Adjust as necessary if your measurements are off. The elevator may not go all the way to the top.
- 8
  Print on the board the height in feet of the building at your final mark. Print half the building height in feet at the adjusted halfway mark. Place a zero at the mark you made at the bottom of the elevator. You now have a calibrated altimeter.

Nature