Category archives: Physics

The coffee-ring effect

The coffee-ring effect

MaterialsPhysics

By Mireia Altimira

Have you ever observed how a drop of coffee dries? As water evaporates, its suspended particles are deposited in a ring-like fashion in a phenomenon known as the coffee-ring effect. Obviously, this effect is undesirable in the numerous practical applications that require a uniform coating. However, the way to avoid it has remained unknown. The […]

Solid state physics could teach us how to quantize gravity: Horava’s theory

Solid state physics could teach us how to quantize gravity: Horava’s theory

CosmologyPhysicsQuantum physics

By Mario Herrero-Valea

One of hottest topics in theoretical physics today is, of course, quantum gravity. The fact that, almost a hundred years after the born of the quantum theory, we still not have a functional theory that describes gravity at a microscopic level has become one of the most attractive problems for the majority of physicists (even […]

Read it twice: heat transfer from a cooler body to a hotter body

Read it twice: heat transfer from a cooler body to a hotter body

Physics

By Francisco R. Villatoro

Without any conflict with the second law of thermodynamics, heat can flow from a cooler but constantly heated body to another thermally connected and constantly hotter body. This anomalous heat transfer has been demonstrated in a two-phase liquid-vapor system composed of a Rayleigh–Bénard convection (RBC) cell filled one-half with normal liquid helium and one-half with […]

Triassic lungs: Unidirectional flow in alligators’ breathing

Triassic lungs: Unidirectional flow in alligators’ breathing

BiologyEvolutionPhysics

By Mireia Altimira

The lungs of birds move air in only one direction during both inspiration and expiration through a set of tubular gas-exchanging bronchi called parabronchi. On the other hand, in the lungs of mammals and other vertebrates, air moves tidally into and out of terminal gas-exchange structures, called alveoli (Figure 1). The work carried out by […]

Laser spectrochemistry beyond Earth’s boundaries: Curiosity’s Chemcam

Laser spectrochemistry beyond Earth’s boundaries: Curiosity’s Chemcam

ChemistryPhysicsRobotics

By Paola Vega

It is well known that an accurate and energetic laser shot can melt, ionize and excite the material in which the light is focused, creating very bright plasmas after the interaction. Valuable information can be obtained from the light emitted by the plasma, such as the elemental composition of the material itself or the environment […]