This June 1974 film is of implosion testing of the Tektronix 4012 DVST (direct view storage tube) graphics terminal.

We believe the specification was to survive a 2 pound ball raised to an elevation to impart 5 lb-ft of energy, which it passed.

The second test, oddly complex impact with the pin and the weighted impact, successfully showed that no shrapnel escaped the product, even though the tube imploded. The glass response in slow motion is remarkable.

The next head-on impact appears to be much greater than the first, and the faceplate breaks. There weren't any large pieces that came forward and the force of the implosion properly drew debris inwards.

The most important aspect of the testing was that no significant glass or ceramic shrapnel leaves the plane of the faceplate.