Weather affects everyone's life. For some people, such as aviation pilots, boaters and farmers, weather is extremely important. Yet we have no control over this phenomenon of nature. We can, however use weather instruments to help predict what weather conditions can be expected in upcoming hours or days. This can help people make plans and even prevent serious injuries and death in the event of dangerous approaching storms.
Instructions
Basic Weather Instruments
1. Thermometers: Read the temperature on a thermometer by looking at the top of the liquid in the tube and matching it to the marks on the scale that runs alongside the tube. The fluid in the thermometer (alcohol, mercury, etc.) rises higher in the tube (due to expansion) as heat increases. Common scales used for weather reporting are Fahrenheit and Celsius.
2. Barometers: Write down the air pressure value pointed to by the needle on a barometer, such as 29.5 millibars. Hours later, again observe where the needle is pointing, and record this number. Note whether this number is higher or lower than the previous reading. Meteorologists use barometers to detect trends in air pressure. A rising value indicates fair or clearing weather, while a falling trend can signify stormy weather approaching.
3. Anemometer - Measure wind speed with an anemometer. Whether it's a hand-held unit or one mounted on a rooftop, wind pushes against cups, turning a dial or triggering an electronic counter, which tabulates the number of rotations per given interval. Wind speed can be used by weathermen to predict how long it will take for an approaching storm to arrive.
4. Wind Vanes - Observe which direction the wind is blowing by using a wind vane. Note the direction in which the wind vane's arrow points. When meteorologists report wind direction, they are referring to the direction from which the wind is coming. A northeast wind, therefore, means the wind is coming from the northeast.
5. Sling Psychrometer - Wet the cloth of one of the two thermometers mounted on a sling psychrometer, and swing it around in the air several times. Evaporation is a cooling process. So, as water evaporates from the thermometer's wet bulb, the temperature will go lower. A sling psychrometer measures relative humidity. The drier the air, the more rapidly the cloth will dry, and the lower the temperature.
6. Rain Gauge - Measure rainfall with a rain gauge. Record the amount of rainfall (in inches) indicated. Empty the rain gauge after a storm and you have noted the amount of rainfall on the gauge's scale. During long periods of rain, several days for example, you may want to take a reading every 24 hous and then empty the gauge by dumping out the water. When the storm passes, add together the rainfall from each day to find the total amount for the storm. Another type of precipitation is snow, which is simply measured using a ruler or yard stick stuck in snow to read its depth. For an accurate reading, measure snow height in an open area, free of snow drifts or accumulating snow.
7. Combining the readings (and trends) from various basic instruments can help meteorologists forecast the weather. For example, if the wind direction moves from east to northeast, the barometer is 30.10 or above and falling rapidly, precipitation can be expected within the next 12 to 24 hours. If the temperature is warm, the precipitation will be rain. If it's cold, snow may be the result.
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