Impact testing machine
Effectively like an IZOD test but with very small samples
Broken samples of acrylic, nylon, aluminium, zinc, extruded mild steel, quenched high-carbon steel, quenched and tempered high-carbon steel
There are two weights on the machine. The heavier one is removed for brittle materials
These are the collated results from a large number of students. The Zn is anomalous because it has a limited number of slip systems.