Images Dated 6th August 2003

Technician uses an isotope ratio mass spectrometer

MODEL RELEASED. Isotope ratio mass spectrometry. Technician observes the visual display unit of an isotope ratio mass spectrometer during the analysis of a sample. A mass spectrometer works by deflecting a beam of charged atoms in a vacuum by passing it through an electric or magnetic field. Each element has a different charge to mass ratio and so will be deflected by a different amount. This "spectrum" of ions can be detected electrically and analysed. The technique can be used to detect very low concentrations of chemicals and molecules in a sample

© TEK IMAGE/SCIENCE PHOTO LIBRARY

Thunberg spirea, SEM

Thunberg spirea (Spiraea thunbergii). Coloured scanning electron micrograph (SEM) of a flower of Thunberg spirea, a member of the rose family, found in China and Japan. The small (8 millimetre diameter) flowers have five petals. They appear on the branches in late winter to early spring before the new leaves appear. The flower contains the reproductive parts of the plant. The stamens, comprising filaments topped by pollen grain (male sex cell) producing anthers (pale green), surround the stigmas (orange). The stigma is the top of the carpel in which the ovules (female sex cells) are located. Magnification unknown

© SUSUMU NISHINAGA/SCIENCE PHOTO LIBRARY