ratio of word probabilities predicted from brain for knife and saw

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knife

saw

top 10 words in brain distribution (in article):
iron blade steel handle cut metal tool nail hammer hand
top 10 words in brain distribution (in article):
blade tooth steel cut material type hand modern tool edge
top 10 words in brain distribution (not in article):
head hair whip breast design size century sword bra rope
top 10 words in brain distribution (not in article):
tea iron century metal pearl design form handle shape head
times more probable under knife 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under saw
(words not in the model)
A knife'" is a handheld sharp-edged instrument consisting of a handle attached to a blade that is used for cutting. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools. History. The earliest knives were shaped by knapping (percussive flaking) of rock, particularly harder rocks such as obsidian and flint. During the Paleolithic era Homo habilis likely made similar tools out of wood, bone, and similar perishable materials that have not survived. As recent as five thousand years ago, as advances in metallurgy progressed, stone, wood, and bone blades were gradually succeeded by copper, bronze, iron, and eventually steel. The first metal (copper) knives were symmetrical double edged daggers, which copied the earlier flint daggers. In Europe the first single edged knives appeared during the middle bronze age. Modern knives may be made from many different materials such as alloy tool steels, carbon fiber, ceramics, and titanium. Materials and construction. Today, knives come in many forms but can be generally categorized between two broad types: fixed blade knives and folding, or pocket, knives. Modern knives consist of a "blade" (1'") and "handle" (2'"). The blade edge can be plain or serrated or a combination of both. The handle, used to grip and manipulate the blade safely, may include the "tang", a portion of the blade that extends into the handle. Knives are made with partial (extending part way into the handle) and full (extending the full length of the handle, often visible on top and bottom) tangs. The handle can also include a bolster, which is a piece of material used to balance the knife, usually brass or other metal, at the front of the handle where it meets the blade. The A saw is a tool that uses a hard blade or wire with an abrasive edge to cut through softer materials. The cutting edge of a saw is either a serrated blade or an abrasive. A saw may be worked by hand, or powered by steam, water, electric or other power. In a modern serrated saw, each tooth is bent to a precise angle called its "set". The set of the teeth is determined by the kind of cut the saw is intended to make. For example, a "rip saw" has a tooth set that is similar to the angle used on a chisel. The idea is to have the teeth rip or tear the material apart. Some teeth are usually splayed slightly to each side the blade, so that the cut width (kerf) is wider than the blade itself and the blade does not bind in the cut. The kerf of the blade is adjusted with a tool called a saw tooth setter. An abrasive saw uses an abrasive disc or band for cutting, rather than a serrated blade. According to Chinese tradition, the saw was invented by Lu Ban. In Greek mythology, Talos, the nephew of Daedalos, invented the saw. In fact, saws date back to prehistory, and likely evolved from Neolithic tools or bone tools. The early ancestors of man, in the Pleistocene era, likely first used a jaw bone of 5 bovid animals as a saw. Types of saw blades and the cuts they make. Blade teeth are of two general types: Tool steel or carbide. Carbide is harder and holds a sharp edge much longer. Materials used for saws. There are several materials used in saws, with each of its own specifications.