Thermal image targets

A target which simulates a thermal image, thus re-creating the thermal signature of, eg. a military tank, comprises a number of containers 2, each containing a super-cooled medium, eg. sodium acetatetrihydrate (CH3COONa3H2O),which can be triggered or nucleated, eg. by dropping into each container a small crystal of the salt in the solid phase, to rise to a phase transition temperature at which it emanates heat. Each container 2 also contains a plurality of capsules which are crushed or broken when a shell hits the container, the capsules containing chemicals which provide a hit indication. These chemicals may comprise a chemical pair which react to give chemiluminence or a pyrotechnic mixture, or chemicals which react to provide a strong exothermic reaction. The capsules may alternatively contain a single spontaneously flammable material. The target may be used in the training of military personnel in the use of infrared sights, or as decoy targets for use in a battle situation. <IMAGE>