Tempered and plate glass are manufactured to produce very different fracture patterns when they break.
The particular mechanisms of fracture are difficult to visualize between the two glass types.
Veryst constructed a test frame with a pendulum impact to compare the fracturing of tempered and plate glass using a high speed camera. Tempered glass is manufactured with a compressive stress on the two outer surfaces that both increase its strength and cause it to break into many small pieces when broken. Plate glass, lacking that compressive stress, will break both into larger pieces and at lower impact forces.