to sum up the water panic

To summarize the bottled water vs. tap water vs. other water wars: this subject plays tricks with the impulsive nature of an everyday consumer. More so, it is related to intellectual dishonesty. It is enough to allude to the fact that tap water contains lead, present due to the soldered pipes, and a consumer is heading for the corner convenience store to stock up on a gallon of designer water. Though it is also enough to mention that a bottle of spring water was found to contain more than a minimal level of sodium, or, even more seriously alleged, a trace of pesticide, and the consumer is ready to rationalize that the good ol' tap water is the God's gift to humans.

• Tap water rules only when it contains lowest amounts of lead and other heavy metals, and the local water authority is certified by an independent lab to produce water having trace metals below EPA limits. It is also important to consider whether the chemical is regulated or non-regulated (see this link http://www.ewg.org/tapwater/findings.php) Other than that, tap water contains low-to-medium low levels of sodium and iron, which are basic necessities for any person.

• Bottled water is still a hands-down winner for areas contaminated with industrial pollutants or agricultural chemicals. Just because trace pesticide was found in bottled water out East, there is no reason to start a lemming run.

• also important to keep in mind: bottled companies often launch smear campaigns against each other (which sometimes backfire when they get out of control), causing a major skew in public perception.

• but the most important thing to remember for the upcoming summer - if you are planning to do any strenuous work that will cause you to lose electrolytes through seating and urination, you are better off drinking sports drinks.

There is a mathematical formula for perfect beer foam

CHICAGO (Reuters) - A mathematical formula can now predict how the frothy head on a beer changes over time, a finding that may have a wide range of commercial uses beyond pulling the perfect pint, U.S. researchers said on Wednesday.

The formula explains how the tiny bubbles that make up foam grow -- an explanation that could lead to the development of products such as metal shrink wrap.

The possibilities include "the heat treatment of metals or even controlling the head on a pint of beer," Robert MacPherson of Princeton University in New Jersey and David Srolovitz of Yeshiva University in New York report in the journal Nature.

Foam is made up of many tiny bubbles that scientists think of as cells with boundaries. The new formula calculates how these microstructures grow.

These tiny structures or grains are abundant in nature, making up the foam on a beach or the pebble in your shoe. They also can be found in man-made materials such as ceramics or metals.

"What the theory does is it tells you how the size of every single bubble will evolve in time," Srolovitz said in a telephone interview.

David Kinderlehrer, a mathematician at Carnegie Mellon University in Pittsburgh, said the finding will help materials scientists concoct a number of newfangled materials by rearranging the grains in various materials using computer simulation.

"It tells you how an individual grain grows by itself until something happens to it. That is very important for understanding how to process material," Kinderlehrer said in a telephone interview.

In metal, that means striking the right balance.

"The strength of a metal depends on grain size. As you make smaller and smaller grains, the metal gets stronger and stronger but it also gets more brittle," Srolovitz said.

"For a particular application you want the grain size that represents a compromise between as strong as you can get and as brittle as you can live with," Srolovitz said.

Kinderlehrer said new materials now under study are batteries that do not corrode and shrink-wrap metals that could be used to repair nuclear power plants -- without shutting them down.

"A lot of things we can only imagine," said Kinderlehrer, who wrote a commentary accompanying the study.