IBM scientists have measured the distribution of electrical charges in tubes of carbon that measure less than 2 nanometers in diameter, 50,000 times thinner than a strand of human hair. This novel technique, which relies on the interactions between electrons and phonons, provides a detailed understanding of the electrical behavior of carbon nanotubes, a material that shows promise as a building block for much smaller, faster and lower power computer chips compared to today's conventional silicon transistors. Credit: IBM

IBM scientists have measured distribution of electrical charges in tubes of carbon that measure less than 2 nanometers in diameter, 50,000 times thinner than a strand of human hair. The technique provides a better understanding of the electrical behavior of carbon nanotubes, a material that could lead to smaller, faster and lower power computer chips.

Why Is The Ocean Salty?

Today’s ocean salt has ancient origins. As the earth formed, gases spewing from its interior released salt ions that reached the ocean via rainfall or land runoff.

Now, the ocean’s salinity is basically constant. “Ions aren’t being removed or supplied in an appreciable amount,” McKinley says. “The removal and sources that do exist are so small and the reservoir is so large that those ions just stay in the water.” For example, she says, “Each year, runoff from the land adds only 0.00005 percent of total ocean salts.”

In lakes, relatively rapid turnover of water and its dissolved salts keeps the water fresh – a water droplet and its ions will stay in Lake Superior for about 200 years, compared to roughly 100 to 200 million years in the ocean. “Even if you did have any accumulation of an ion in a lake, it would be washed out quickly,” McKinley explains.

Ocean salts, however, have no place to go. “The ions that were put there long ago have managed to stick around,” McKinley says. “There is geologic evidence that the saltiness of the water has been the way that it is for at least a billion years.”