Serrated blade
A serrated blade is a type of blade used on saws and on some knives or scissors. It is also known as a dentated, sawtooth, or toothed blade. Serrations give the blade's cutting edge less contact area than a smooth blade, which increases the applied pressure at each point of contact, and the points of contact are at a sharper angle to the material being cut. This causes a cutting action that involves many small splits in the surface of the material being cut, which cumulatively serve to cut the material along the line of the blade . It can also give more structural integrity to a thinner blade, like how a fan fold is stronger than flat paper. This is because the zig-zag pattern resists force from different angles, called the "moments of area". Cuts made with a serrated blade are typically less smooth and precise than cuts made with a smooth blade. Serrated blades can be more difficult to sharpen using a whetstone or rotary sharpener than a non-serrated, however, they can be easily sharpened with a diamond. Serrated blades tend to stay sharper longer than a similar straight edged blade. A serrated blade  has a faster cut but a plain edge has a cleaner cut. Some prefer a serrated blade on a pocket knife.