Dynamic mechanical analyser specimens. These pieces of polymer-based material are used by the dynamic mechanical analyser (DMA) as temperature reference specimens, against which test samples are compared. The DMA machine measures alterations in an object's mechanical properties due to changes in temperature. The properties affected include the object's dimensions, how it responds to stresses and whether it softens or deforms. One aspect that the DMA analyses is plate twist geometry, where it looks at how much a material warps when exposed to different temperatures. Photographed at the National Physical Laboratory in Teddington, UK. The DMA apparatus can be seen in H305/274.