What does it mean?
As you and your kids go about monitoring the readings that come from your equipment you may notice that the weather conditions outside change as the readings change. If you are able to keep a chart of the readings make a note of what the weather is like from a visual perspective and what happened the next day. After a while you may notice that if a certain string of numbers show up, the weather is likely to change like before.
How weather works.
Before you start collecting all the tools and instrumentation for your backyard weather station it is a good idea to have some idea of how weather works. In this way you can gauge where and how to set-up and use the instruments while assessing what you may want to add to the station as the kids and adults learn. Weather starts essentially with the sun and its heating rays. The heat hits the earth, heating its land and water masses. The earth and water warms causing air to rise. Depending upon how warm the land and water get the air rises faster causing wind as it meets previously warm air that is now cool and falling back to earth to be warmed again.
Across a land mass the process is uneven and the earth is spinning causing areas where there is high pressure and low pressure because the air is rising and falling at different rates with different elements mixed in with the air (water vapor.) As the; earth turns, the ground and water heat, the air rises and falls picking up other stuff like water droplets/moisture and temperature changes high pressure regions and low pressure regions move across the globe causing fronts where changes happen between the two pressures. Outside of knowing what to wear each day, what a weather station does is tell you whether a front is coming, here or going depending upon: temperature, water content, wind and direction.
The instrumentation.
Ok, simplistic yes but that's about it for how weather works. Now measuring where in the cycle your backyard happens to be can start. A thermometer placed in the shade will give you a good idea of the temperature. You can build one or pick up a decent one at the hardware store. If building one you might want to check out a specific how to site on the topic but basically; buy a glass tube and one inch in diameter, fill it with mercury to 32 inches high and suck out all the air. Or, you can buy one as this is not a child’s task. An anemometer will help you measure the wind speed. This device has four half ping-pong type balls on the end of sticks attached to one another in the shape of a cross. It also tends to have a weather vane attached to the top of it so that you can tell which way the wind is coming from.
The last two pieces of instrumentation you’ll need to pick up are a barometer and a rain gauge. The barometer tells you whether the air pressure is rising or falling. A rising barometer tells you fair weather is coming and a dropping pressure poor weather. The rain gage is simply a 1 inch plastic tube with depth markings placed on the sides. It needs to be placed in an open place where wind is less likely to blow added rain into it.
