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About "Ask A Scientist!"

On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.

Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.

Previous Week's Question Published: 5 June, 2003 Next Week's Question
The weather goes around and around, just like Earth
Question
What makes the weather change?

Question
Our weather changes because we live on a round, rotating planet with a bumpy surface. The roundness of the planet causes its equator to be heated more than the poles by the sun. The relatively warm air over the equator vertically expands, causing there to be more air over horizontal surfaces aloft over the equator than over the poles. This in turn causes air aloft over the equator to spread toward the poles. This poleward spreading air is deflected to the east by the turning of the earth. This is why winds aloft generally blow from west to east.

This eastward moving air strikes mountains on the earth's surface, creating atmospheric waves which move eastward, too. Air rises on the east side of each wave, and sinks on the west side. Clouds and rain or snow form in the rising air, while the weather is usually fair under the sinking air. As the waves move eastward, so do the alternating regions of fair and stormy weather. New waves continue to form by winds striking the mountains, resulting in new patterns of fair and stormy weather which move eastward with the waves. On the earth's surface, we observe these alternating patterns by changes in the weather: Fair one day and stormy the next.

Since there are many mountains of different sizes on the earth, and since winds don't always strike them with the same speed, then many different kinds of waves can form. These waves can interfere with each other, producing very complicated weather patterns. This is why the weather sometimes doesn't change, with prolonged periods of fair or stormy conditions. This is also why weather changes are sometimes difficult to predict, especially more than a few days in advance.

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