The thermometer is used to gauge weather temperature. When liquid inside a thermometer heats up, it expands and moves up the tube in which it is enclosed. Kids can measure the weather temperature by putting an outdoor thermometer on a windowsill or other covered area five feet or more above the ground. They can collect data over a period of several days to weeks at regular time and date intervals. Kids can use either Fahrenheit or Celsius measurement for temperature gauge. Fahrenheit measures water on a scale from freezing to boiling, or 32 degrees to 212 degrees Fahrenheit. Celsius defines the freezing point as zero degrees and the boiling point as 100 degrees. Many outdoor thermometers will have both the Fahrenheit and Celsius scale, but Fahrenheit is the most commonly used temperature measurement in the United States. Outdoor thermometers are generally available in educational and crafts stores online and for in-store purchase.
An anemometer is an instrument that assesses wind speed. There are different types, including handheld and rotating. Rotating anemometers are activated as the wind passes over cups that are attached to a central point on the body of the device. Wind speed is measured as the cups spin and rotations are counted. A simple electronic anemometer of either type might have a built-in counter that records the number or cup rotations per given amount of time. Kids can also make an anemometer using three cups attached to a central point at even intervals and setting it in a windy area. They can then use a watch with a second hand or a stop watch to measure the number of rotations per second the cups spin to measure the number of spins per minute. Anemometers are available for purchase online and in some home improvement or specialty stores.
Kids can measure air humidity using hygrometer called a sling psychrometer. Two thermometers are connected using a chain or other method. Kids can wrap the end of one thermometer with a wet cloth while the other stays dry and then spin the thermometers around in the air for thirty seconds and record the drop in temperature. This will give them the relative humidity of the air around them. Air that is dry will cause the water in the cloth to evaporate more quickly and the temperature will remain higher. One of the thermometers is wrapped in wet cloth which is secured to the bulb end. NASA recommends using a chart that shows the differences between the bulbs temperatures and how it affects relative humidity for accurate measurement. Sling psychrometers with wet/dry bulbs are also available for purchase online and in home supply stores.
A barometer gauges atmospheric pressure and helps predict future weather conditions by detecting changes in air pressure. Kids can make a barometer by securing plastic wrap over the top of a can with a rubber band and gluing or taping a 3- to 4-inch straw to the center. There should be no leaks in the plastic for best results. Low air pressure will cause the plastic to expand and the straw will point downward, whereas high air pressure will put pressure on the plastic and make it cave in, which will cause the straw to point upward. Kids can take measurements at regular intervals over a set time frame to gauge the effects different weather patterns have on barometric pressure. Electronic devices and liquid meters are also available for purchase to measure barometric pressure.