Postcards from the Planet

Many organisms - including barnacles and mussels - inhabit the rocky and sandy intertidal areas of the Pacific Ocean in the Northwest.

A study of the Pacific Ocean waters off the coast of Tatoosh Island (Washington State) measured water pH, salinity and temperature every half-hour for eight years. Results were dramatic and showed that the acidity was rising sharply, shown by a fast decline in ocean pH. The study also showed that the local organisms, particularly the Californian mussel, were quite sensitive to CO2 changes. You can read about it here: Marine Life faces ‘Acid Threat’.

Related Question: What is pH?

One pH definition is: “a logarithmic scale, from 1 to 14, used to describe the acidity or alkalinity of a solution.” Acid things taste tart or sour, like lemons. Alkaline (or basic) things are slippery, like soap. Blood in the human body should be close to 7.4 on the pH scale and is slightly basic. Dissolving carbon dioxide in water makes it more acidic. A pH level of less than 7 indicates an acidic solution while a pH greater than 7 indicates an alkaline solution. 7–which is neutral (neither acidic or basic) is the pH level of distilled water. pH stands for “potential Hydrogen.”

On a logarithmic scale, each increase of one unit–from five to six, for example–represents ten times greater or less. So something that has a pH of 1 is ten times more acidic that something with a pH of 2 (or ten times less basic).

Another logarithmic scale that is used in science is the Richter scale, used to measure the strength of earthquakes. On the Richter scale, an earthquake measuring 5 releases ten times the energy of an earthquakes measuring 4; an earthquake measuring 6 releases 100 (ten times ten) times the energy of an earthquake measuring 4.

The short version is: remember that the difference between a pH of 4 and a pH of 3 is much more than just one unit. So pH 3 is very much more acidic than pH 4, because it is on a logarithmic scale!

Dictionary Definition:

pH is the degree of acidity or alkalinity of a solution; it is the logarithm of the reciprocal of the hydrogen-ion concentration in gram equivalents per liter of solution (Ex: .0000001 gram atom of hydrogen ion per liter yields a numeric reciprocal of ten million, the log of ten million equals 7, therefore 7 is the pH): a pH of 7, the value for pure distilled water, is regarded as neutral; pH values from 7 to 0 indicate increasing acidity and from 7 to 14 indicate increasing alkalinity (from YourDictionary.com)

Scientists have been working for a long time on understanding the human brain. Fortunately, they’ve made a lot of progress using various imaging techniques. One problem has been how to study the human brain without hurting people — and one answer has been animal studies. Rats are popular for this — even though you might not think your brain has anything in common with a rat’s! Rats are mammals like us, and studying their brains has been very helpful for brain researchers. Now researchers are working on a 3D virtual atlas of the rat’s brain, so that scientists can put together everything they already know and guide future research. Hear about it here: New Program Maps Virtual Rat Brain In 3D : NPR.
Scientists plan to work on an atlas of the human brain as well. That will be fascinating and may lead to new insights about human biology and behavior. (But can they help me find my car keys?)