Letters to the Editor

January 26, 1999

The physics of bottled soda

To the editor:

I really like Wally McClure and respect him and his efforts and ideas very much. The article and its praise were well deserved.

He really should rethink his idea about the soda bottles, however.

I would guess that his assumption is based on having less pressure and less hissing when reopening the bottle after squeezing out extra air before resealing it. The reason that soda goes flat is due to escaping carbon dioxide. It is dissolved into the soda and held there by pressure.

To preserve more of the CO2 content after opening a bottle, it can be cooled, pressurized or both. Pressure keeps the gases dissolved in a liquid, and cooling will reduce molecular motion and slow the escape.


To pressurize the soda, additional air could be pumped into the bottle to increase the pressure. If the bottle is squeezed to remove some of the air and then sealed, the tendency of the bottle to try to return to its full shape and volume will actually lower the internal pressure and allow even more gas to escape from the soda by creating a lower pressure (partial vacuum) inside.

The reason it will hiss less when reopened is not because less gas has escaped from the soda but rather that more gas would be required to escape to build the pressure as high because it must first overcome the partial vacuum. This would actually tend to make the soda even flatter.

Sorry, Wally.

Thanks for all of the other good ideas and keep up the good work!

Stephen Monn

Saint James School

History text is mistaken

To the editor:

One year ago I wrote to Washington County Superintendent of Schools, Herman Bartlett, offering to present Maryland frontier history to area students through living history interpretations. Although this letter has never been addressed by Bartlett personally, a reply was written by Ellen Hayes.

She informed me that Washington County history is taught in the third grade but the county does not have a specific text to assist with the instruction of this unit. Maryland history is taught to fourth graders by using two textbooks. One of those is "Our Maryland" by Jane Egan and Jeanne McGinnis, 1987.

I cautioned Hayes about the 1987 edition of this book, stating that the frontier section has many mistakes, but I heard no more from her.

The purpose of this letter is to caution parents that, if their children are being taught with this 1987 edition of "Our Maryland," the book contains 13 mistakes in five pages in the section entitled "Life on the Moving Frontier." The mistakes consist of wrong people, wrong places, wrong events and wrong dates. A later (1995) revision has been corrected, but I don't know if all students have access to this copy.

Raleigh Boaze


Visa believes in Year Zero

To the editor:

At the risk of being called poorly educated, even though I've been through college, I herewith submit my comments on the proper time to start the next millennium. I agree with William Baker's English lesson that he gave us Sunday, Jan. 17. But I have a problem with his math.

He says there is no year Zero. I disagree. Nothing ever begins one year old, not even centuries or millenniums. No people either. When a baby is born, he is not one year old. He is at zero age. Yes, he is in his first year, working on it. But he doesn't celebrate his first birthday until he has lived one full year, and that year is behind him. He then will work on his second.

If that kid lives until he is 1999, he will have 1999 years behind him and will then be in his 2000th year, working on it. When he arrives at 2000, he will have 2000 years behind him, and so celebrates his 2000th birthday, the end of a millennium. Note all those zeros.

Yes, there are many so-called authorities who agree with Baker; many others agree with me. But a few very important people in the financial world also agree with me. Both my charge cards, Visa and Master Card, tell me my cards will expire in year 00. No, not in 01, but in 00. No Zero year? Are my charge cards in some kind of never-never-land limbo? No, they are just working on the first year of the new millennium!

Louise Weller


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