Negative Poisson Ratio — Why you can put a cork back in a wine bottle

Most materials, when squeezed at one end, bulge at the other.

Cork distributes the load and when compressed at one end narrows along its length.

That's why you can put it back in the bottle.

Don't believe me?

Try it in the privacy of your own home.

Scientists over the years have experimented with materials with this characteristic, termed a negative Poisson ratio after the French scientist who studied the phenomenon.

Such materials also get thicker when stretched (below).

The New York Times called one such substance "anti-rubber" when it was described in an article published in Science magazine.

Contrast that with the behavior of most materials such as that below

which become thinner when stretched.

Confused?

Read what University of Wisconsin materials scientist Rod Lakes, the creator of "anti-rubber," has to say about the subject on his website.