It's always been interesting for me to note the differences in weather patterns across the country. From the summertime heat of Arizona to the wintertime cold of North Dakota, from the hurricanes and humidity of the southeast to the mild wetness of the Pacific Northwest . . . what makes the weather so different in each different region?
People have been interested in the weather since at least the days of Noah. And with good reason--it has an impact on pretty much every area of our lives. Even with all our technological advances we can't do anything to change the weather. Only God can control the weather, and although that's frustrating to some people, it's still the reality of life.
Since weather is so important to so many people, it's only natural that people always want to know what the weather is going to be. Weather forecasting appears in many places throughout the Bible and other ancient records. Many families have memories of relatives who could almost unerringly predict the weather. And in this issue's Give it a Try, we'll learn how to make our own weather station to help make our own weather forecasts!
Professional weather forecasters, or meteorologists, use very sophisticated instruments and supercomputers to make their predictions. The instruments we'll be making will not be very precise or accurately calibrated, but they should be enough for you to make some basic forecasts.
The first weather instrument we'll make is a barometer. To do this, you'll need a clear glass or jar, a clear drinking straw, a ruler, and a small plug to put into the straw. (Modeling clay, Silly Putty®, or chewing gum will work for the plug.) You'll also need a couple pieces of tape, some water, and just a bit of food coloring.
Making your barometer is simple. Just fill your glass about half-full of water. Add a drop or two of food coloring and stir it in with the straw. Place the straw into the glass, straight up along one side, but don't quite let it touch the bottom of the glass. Tape the straw in place. Now, act like you're going to slowly take a sip of water through the straw, but stop when the colored water in the straw rises to about halfway between the water level and the top of the glass. Pinch the straw to keep the water from running back out of the straw, then firmly push your plug onto the top of the straw. You should be able to see the colored water through the sides of the straw. The water level in the straw should be an inch or two above the water level in the glass.
Now, use your ruler to measure the height of the colored water in the straw every day. You should notice that the water level goes up and down periodically. This is because of air pressure acting on the water in the glass. On a "high pressure day," which is normally clear, the water level in the straw will be high. On a "low pressure day," the water level will be lower. Low pressure, or "falling barometers," often means a period of bad weather is moving in.
Our next instrument is a hygrometer, which is used to measure the humidity in the air. To make this instrument, you'll need a small piece of stiff, thick paper (card stock works well), a thumbtack, a small finishing nail, some glue (hot glue works best), a dime, a piece of long, straight hair about eight inches long (Mom better handle the scissors!) and a few pieces of cardboard.
Start by cutting out three pieces of cardboard about ten inches long and five inches wide. Glue them together so you end up with one thick piece. This will be the mounting board. Now, take your thick paper and trace an isosceles triangle onto it, about four inches tall and two inches wide at the bottom. Cut out the triangle and use your finishing nail to poke a hole in the center, about half an inch from the bottom end. Position the triangle on the mounting board about one inch from the bottom with the long, pointed end pointing to the right. Push the thumbtack through the hole in the triangle into the mounting board. This will be your pointer. Leave the thumbtack loose so the pointer can rotate freely.
Now, tape the dime to the sharp end of the pointer, just barely leaving the tip of the pointer visible so you can take your measurements later. Then, glue one end of the hair to the pointer about halfway between the dime and the thumbtack. Allow the glue to dry. Now, holding the pointer still so it points straight to the right, pull the hair straight up and glue the loose ends to the mounting board near the top. After allowing the glue to dry, hang your hygrometer with the pointer at the bottom pointing to the right. Make a mark on the mounting board where the tip of the pointer is located.
On a day of high humidity, the hair will be slightly longer, so the pointer will point slightly lower. On days with lower humidity, the hair will be slightly shorter, so the pointer will point slightly higher. Make your daily observations by using a ruler to measure the distance from the mark on your mounting board to where the pointer is that day.
You probably already know that a thermometer is an instrument to measure temperature. To make your thermometer, you'll need a small bottle with a narrow opening, a clear drinking straw, some water, and food coloring. You'll also need some more modeling clay or Silly Putty® (chewing gum won't work well this time).
To start, roll your clay into a "worm" a few inches long. Wrap this around the drinking straw, right in the middle. Set aside.
Now, fill the bottle halfway with water, then add a few drops of food coloring and stir it up. Fill the bottle with water the rest of the way, clear up to the brim. (You may want to work in the sink for this part so you don't spill the colored water on the carpet!) Take your straw with the clay wrapped around it and place it in the bottle. Press the clay tightly around the straw and the mouth of the bottle to form an airtight seal. Be sure to press the clay down into the mouth of the bottle a little bit. This will force some of the colored water to rise into the straw where you can see it. Use a black marker to carefully mark the water level on the straw.
As the water in your thermometer heats up, it expands and forces the water higher in the straw. As the water cools down, the water takes less space so it falls lower in the straw. Since the outside air must heat or cool all the water in the bottle, you'll get faster, more accurate readings with a smaller bottle that contains less water.
Your thermometer isn't calibrated to actually tell the temperature in degrees, but you can still take observations by measuring the water level with a ruler. Place your thermometer in a safe place outside, out of the sun. Bring it inside if freezing temperatures are expected--it will burst if you allow the water to freeze. The thermometers you buy normally use mercury to allow them to measure temperatures lower than 32 or higher than 212, which are the limits for your water-based thermometer.
You'll need a journal to keep your weather observations in. Each day, write down the observations you measure from your new weather instruments, along with a general description of the current weather conditions and your predictions for the following day.
After a week or two, compile your observations into a table or graph to see if you notice any trends. Before long, you should be able to make general weather forecasts using your own homemade instruments!
Matthew Lewis, a homeschool graduate, is the web developer, and occasional columnist, for Home School Enrichment Magazine. Matthew is a self-described computer geek who enjoys doing things during his free time which he says would sound much too boring to be mentioned here. You may contact Matthew at matthew@HomeSchoolEnrichment.com
This article was originally published in the Mar/Apr '07 issue of Home School Enrichment Magazine. For more information, visit http://HomeSchoolEnrichment.com