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Meteorologist Tools

 
If you had to measure and predict the weather, what tools would you use?
 

A rake or shovel?

A hammer?

Here you will learn the basic tools of a meteorologist.

 
Pop goes the ear!
 

It’s time to pack the car and visit the great state of Utah. Your trip begins in St. George. After a day of hiking in the sun, you travel north on I-15 to Provo. Heading up Provo Canyon towards the Uintah Mountains, you feel pressure in your ear, and can’t hear what your little sister is saying. Something has happened to your hearing! You yawn, take a drink of soda, and chew some gum to relieve the pressure. Suddenly you feel a crackling pop. Your ears feel better!

 
What happened to your ears?
 

Highlight the box below to see if your answer is correct.

Your ears "popped" because of the weight of the surrounding air. As you travel up the canyon to the higher elevation of the mountains, there is less air pressing on your eardrums. This causes the eardrums to adjust which causes the uncomfortable sensation we call "popping."
 
"Weigh" to go!
 

Compared to a rock or a feather, air does not weigh very much; however, air is a gas made up of tiny molecules of matter. Air has weight. It is pressing all around us. Air pressure is the weight of air in our atmosphere pressing down upon Earth.

 
"Pressing" into the future
 

Meteorologists, the scientists who study the weather, call air pressure "Barometric (bear-o-met-ric) Pressure." A barometer (ba-ro-meter) is a weather instrument used to measure the air pressure. Changes in air pressure usually mean a change in the weather. Stormy weather often occurs after the barometer falls or the air pressure decreases. A Rising barometer is usually an indicator of good or fair weather. Meteorologists learn to use a barometer to predict the weather.

 
BAROMETER - make it yourself!
 

Materials:

  • Clear glass or plastic jar
  • Drinking straw
  • Tape
  • Clay or chewed gum (yuck!)
  • Cold water
  • Food coloring
  • Index card or rubber band to record changes.
 

Procedure:

  1. Fill the jar 1/2 full with cold water.
  2. Add a little food coloring so you can see the water better.
  3. Put the straw in the jar. Tape it to the inside so the bottom of the straw is in the water, but not touching the bottom of the jar.
  4. Suck some water half-way up the straw. Pinch the end or put your finger over it to trap the water in the straw.
  5. Put the clay or gum over the end of the straw to keep the water trapped.
  6. You need to choose a method to record changes in the water level of the straw. Either you can tape the index card to the outside of the jar and mark it daily, or you can move a rubber band up or down around the jar to show the water level in the straw.
  7. Leave your jar where it won't get knocked over.
 
Making Observations:
 
If the water level remains the same or goes higher, air pressure is constant or going up. The weather generally will be calm, settled, and dry. If you notice the water level going down, air pressure is dropping. The weather generally will be more unsettled. A frontal system might be approaching, bringing storms.
 
A sticky situation

Have you ever walked into a bathroom right after someone has taken a hot shower? How does the air feel? Does your skin feel kind of sticky? What you are feeling is water in the air. The water is in the form of a gas. Scientists call this gas "water vapor."

 
Desert areas do not get a lot of rain or snow during the year. For example, there is usually much less water vapor in the air in St. George. Areas located near oceans like South Carolina [or some other example to mirror the example of St. George] almost always have more moisture in the air.
 
Measuring relative humidity
 

Weather forecasters often mention the term "relative humidity." This term refers to the amount of water vapor actually in the air as compared to the amount of water the air can hold at that temperature. The relative humidity is always given as a percentage.

 

Materials:

  • Two thermometers
  • One paper towel
  • Paper
 

Procedure

  1. Place the two thermometers side by side on your desk or a table.
  2. Compare and record the temperatures of both thermometers. They should display the same temperature.
  3. On one thermometer, place the paper towel around only the bulb of the thermometer.
  4. Wet the papertowel.
  5. Using the paper, fan some air across the thermometers for a minute or two.
  6. Record the temperatures of both thermometers in degrees Fahrenheit.
  7. Notice that the thermometer with the paper towel on the bulb shows a lower temperature than the dry bulb thermometer.
  8. Explain why the temperature changed on one of the thermometers.
 

Cool it!

Have you ever gotten out of a swimming pool and felt cold - even on a hot day?

 
In addition to the tools that you learned about on this page remember the wind vane that you learned to make earlier on the Windward Ho! Web page.
 

Download the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 4th grade science core.


Updated October 24, 2008 by: Glen Westbroek

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