Belgian scientists have put a different kind of fizz into physics. They have studied that fleeting mystery of the foaming tankard — the antibubble. Antibubbles move down the glass instead of up.

If a bubble is a thin film of liquid in air that encloses a pocket of air, an antibubble is a thin film of air made inside a liquid, enclosing a pocket of liquid.

Antibubbles can be made by pouring a liquid containing a surfactant into yet more liquid containing a surfactant. The rate at which the liquid is poured is critical. Antibubbles cannot be made in pure water, pure alcohol or pure oil.

But they can be made in beer, which contains a protein that acts as a surfactant. They repeated the phenomenon in a glass of Belgian beer, thus confirming, according to the Institute of Physics in London. — The Guardian

Fossil teeth

Six fossil teeth found in an Ethiopian desert and dated at about 5.2 million years may be from a previously unknown type of pre-human primate that was among the first to evolve from the common ancestor of humans and apes, a study suggests.

The teeth have distinctive features that are thought to have existed among the first hominids to emerge after the ape and human lineages evolved apart some six to eight million years ago, researchers said.

A canine tooth in the assembly closely resembles teeth found in apes.

The researchers say that the canine teeth were arranged so that they were sharpened against the lower premolars.

This characteristic is common in both ancient and modern apes, they said. — AP