Tying a smoke ring in a knot sounds impossible - but University of Chicago physicists have done something similar by creating a vortex knot for the first time, in a container of fluid.
Animals can focus their sense of smell in much the same way as humans focus their eyes, helping them detect predators and search out food.
There's a well-known experiment in which cornstarch is added to water, turning it into a rather odd substance known as oobleck.
Human beings - along with all jawed vertebrates on Earth - are descended from a fossil fish that looks a lot like today's sharks.
A change in the social position of a rhesus macaque can affect the expression of nearly 1,000 genes, perhaps partly explaining why poorer people tend to have worse health outcomes.
A new chemical analysis of lunar material collected by Apollo astronauts in the 1970s appears to disprove theories that the moon was created through a massive collision between Earth and a Mars-sized object 4.5 billion years ago.
Numbers above three are incomprehensible to people who don't speak a language that uses symbols for counting, say researchers at the University of Chicago.