A hygrometer (a device for measuring relative humidity) can be easily constructed from ordinary household devices and materials. It can be used in conjunction with other weather instruments to gauge and predict weather patterns. This is a fun, yet very scientific, device that the entire family can gather together to build, requiring little time, effort and just basic materials. With such a device, one can forecast the development of weather cells into storms, or even measure the heat index (for tolerance). A perfect project for all members of the family, especially the younger ones, helping them to learn climate patterns in their own backyard. A basic weather station can be constructed for the patio and reasonably accurate measurements can be taken and compiled over time, using the hygrometer and the other instruments.
To build a hygrometer, one has to purchase two very good quality thermometers that are essentially both very accurate. It is not so much knowing the precise air temperatures, but the dry and wet bulb readings. To facilitate this, the next thing that has to be purchased is a one foot long cotton shoe lace, in which the ends have to be removed. This becomes the tip for the wet bulb readings. Through the wet and dry bulb readings comes the relative humidity measurements. Separating the sides and make a sleeve to gingerly roll up the bulbs of one of your purchased thermometers. This essentially transforms a basic thermometer into a hygrometer, for the premise of it is measure relative air humidity from the subtraction of the wet bulb temperature from the air temperature of the other thermometer. These are essentially known as ‘psychrometers.’
Carefully mount both thermometers, the “dry bulb” and the “wet bulb” onto a piece of board. Take the “wick”, or the shoelace from the wet bulb and keep it soaked or in a small receptacle of water, if you want to consistently monitor changes in the humidity-in anticipation of coming rain, storm or heat events. The dangling string can be rolled up and wrapped around a nail when not used. This is essentially a project for a family with younger kids-although older kids may find it fascinating. But in conjunction with a homemade barometer and wind vane, kids and parents of all ages can learn a lot about the ever-changing climate around them. It is not considered a very accurate measuring tool, as the thermometers would have to be far more calibrated. But is so easily constructed and fun for all ages.
It can become part of your family’s little weather station. In a world of changing, ever increasing volatile weather patterns, this homemade hygrometer can become a valuable tool in starting to understand some of the changes in weather.
