Split the glass plate.

Grasp the ends of the glass near the dividing line with your hands. Using your wrist, apply gentle pressure along the scratch line to split the glass in half. With just your wrist pressing on the glass, the elbow joint does not need to move.

If the glass panel is curved in shape, you need to lightly bounce the glass and then apply gentle pressure from the back of the glass against the middle point of the scratch line.