Images Dated 29th November 2005

Butterfly proboscis, SEM

Butterfly proboscis. Coloured scanning electron micrograph (SEM) of the coiled tip of a proboscis of a swallowtail butterfly (Papilio sp.). The proboscis is an elongated hollow tube that is used to suck up nectar and other liquids. The spikes protruding from the coiled tip are sensilla, which are sensory organs that allow the butterfly to taste its food

© SUSUMU NISHINAGA/SCIENCE PHOTO LIBRARY

James Clark Maxwell with his demon

James Clark Maxwell and his demon, artwork. Maxwell (1831-1879) is best known for his laws of electromagnetism, which laid the foundations for modern physics. His "demon" was a thought experiment to question the Second Law of Thermodynamics: the entropy of a system tends to increase. This means that a hot region cannot draw heat from a colder region. Maxwell's demon is a being that can operate a door between a hot and cold gas, opening it to allow a fast-moving (hot) molecule to pass to the hot side, or a slow- moving one to pass to the cold side. This would violate the second law. However, as the demon requires energy to distinguish between fast and slow approaching molecules, and to operate the door, the entropy of the system increases anyway

© BILL SANDERSON/SCIENCE PHOTO LIBRARY

Sunflower pollen, SEM

Sunflower pollen grains. Coloured scanning electron micrograph (SEM) of pollen grains from the sunflower (Helianthus annuus). The grains have a spiked outer wall (exine), which may assist in their dispersal by improving their adherence to pollinating insects. The characteristic surface of pollen grains is used by botanists to recognise and classify plants. Each pollen grain contains a male gamete (reproductive cell) that is intended to fertilise an egg or ovule (female gamete), and initiate the formation of a seed for a new plant. Magnification: x2100 when printed at 10 centimetres tall

© SUSUMU NISHINAGA/SCIENCE PHOTO LIBRARY