Homemade weather instruments
Weather, according to define.com, is "the state of the air or atmosphere with respect to heat or cold, wetness or dryness, calm or storm, clearness or cloudiness or any other meteorological phenomena." Because weather changes quickly, meteorologists use high-tech instruments to forecast the weather over the longer term. Weather forecasting has utilized some level of instruments since the mid-fifteenth century when Nicolas Cusa first developed a hygrometer to measure the relative humidity in the air. Test your meteorological skills with basic weather instruments that you can build at home, and check their accuracy against the modern, high-tech instruments used by professional meteorologists.
Instructions
1. Make a weather vane with ordinary household items. A weather vane points out the direction of the wind and can be made with a shoebox, a compass, a straw, a straight pin, a little clay, cardboard and a pencil. Cut a one-inch square from the cardboard. Cut the square in half on the diagonal to create two triangles. Take one triangle, and slide it flat side first into the slot at one end of the straw. Add a spot of glue to secure the cardboard to the straw. Take the second triangle, and slide it point first into the slot at the other end of the straw. Add a spot of glue to secure the cardboard to the straw. Find the balance point on the straw by balancing the straw on the end of the pencil. Poke a straight pin (like a pin used to pin patterns and fabric together) through the straw at the balance point, and poke the end of the straight pin into the pencil's eraser.
Poke a hole just big enough for the pencil to fit through in the center of the shoebox lid. Place a piece of clay on the end of the pencil and steady the pencil by pushing the clay down on the bottom of the box. Push the shoebox lid on to the box, and double check that the straw spins freely
Set the box out in the open where the wind can hit it without obstructions. Put a compass on the box. When the wind blows the arrow into place you can check the compass and monitor the direction of the wind.
2. Build your own low-tech anemometer, a device deigned to test wind speed. Cut a piece of string 20-inches long. Tie the string around the straight edge of a protractor. Center the string on the protractor. Tape the other end of the string to a ping pong ball. Hang your anemometer in an area free from elements that could obstruct the wind. Place the protractor curved side down. Check the wind speed in your area. If the string hangs at 90 degrees, there is no wind speed. Seventy-five degrees indicates 6.3 mph. Sixty degrees signifies 9.3 mph. At 45 degrees, the wind speed measures 12.2 mph. See Resources for a more detailed list of degrees to wind speed ratings.
3. Make a barometer. Cut the open end off of a large balloon and stretch the balloon over the top of a small coffee can until it is taut. Secure the balloon to the can with a rubber band. Locate the middle of the balloon, and tape a straw across the center point. Allow one end of the straw to stick out beyond the edge of the can. Tape the index card to the can so that the lines on the card act as measurement guides for the straw. Set your barometer in a spot away from windows and doors. Mark a line indicating the straw's position on the card. Check your barometer and watch as the straw rises and falls with changes in the air pressure.
4. Build a hygrometer, an instrument used to measure the relative humidity of the air. Cut an index card in half. Tape each half to opposite sides of a paper cup so that the cards extend beyond the cup's bottom edge and the cup sits upside down with the index card extending up. Poke a hat pin through the center of one card about one-half inch from the top of the card. Locate the center of the straw. Poke the hat pin through the straw's center point and on through the other card to sandwich the straw between the two cards.
Cut strips of blotting paper to make one by one-half inch rectangles. Staple three or four together in a stack, and tape the stack to the top of one end of the straw. Attach clay to the other end of the straw until the straw is evenly weighted on both ends. Test your hygrometer by taking it into the bathroom and running a hot shower or a couple of minutes. Watch your instrument for changes. Changes in humidity will alter the straw's balance.
Tags: wind speed, index card, balance point, cardboard straw, center point, degrees wind, degrees wind speed