Abstract: A flat tweezer formed of a folded plastic material which can be opened to lay flat within the case. The tweezer may be formed from a plastic card with score lines defining the tweezer arms and a hinge coupling the arms.

Abstract: A means of refrigeration is provided for a diffusion cloud chamber, which effects the temperatures required for operation of the cloud chamber by heatsinking a Peltier thermoelectric element with a two-phase saturated substance at equilibrium and constant pressure. Use is made of the fact that a two phase saturated substance at equilibrium and constant pressure is thermodynamically fixed in temperature. By sinking a Peltier thermoelectric element to this substance, the entire temperature difference across the Peltier thermoelectric element is offset below the saturation temperature of the two-phase substance. A diffusion cloud chamber incorporating this refrigerator could utilize ice-water cooling rather than dry ice, and therefore be easily set up in any classroom.