Tool

• 1. Introduction

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  A tool is an object that extends an individual's ability to modify the surrounding environment or accomplish a particular task. That definition sounds simple, but the word hides a sprawling history. Stone artifacts date back to about 2.5 million years ago. A long screwdriver can pry a car's control arm from a ball joint. A telephone can interface between two people in conversation and between each user and a communication network. All three of these are tools, and the gap between them is the puzzle this documentary explores. What counts as a tool, where did the very first ones come from, and why do humans hold a place no other animal occupies? Along the way we will meet an Assyrian king who claims to have invented the water screw pump. We will meet octopuses that gather coconut shells, and a saying that insists all tools can be used as hammers. The story reaches from a hominin carving a carcass to the idea that our tools, in turn, shape us.

• 2. Defining The Object

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  Benjamin Beck published a widely used definition of tool use in 1981, and it has since been modified into a careful, technical sentence. It describes the external employment of an unattached or manipulable attached environmental object to alter the form, position, or condition of another object, another organism, or the user itself. The user must hold and directly manipulate the tool, and be responsible for orienting it properly. Briefer definitions exist alongside Beck's. One calls a tool an object carried or maintained for future use. Another frames it as the use of physical objects other than the animal's own body or appendages as a means to extend physical influence. A tool, in its proto-typical sense, is a solid hand-operated non-biological object with a single broad purpose. It lacks the multiple functions of machines or computers. That narrow image, the hand-operated single-purpose object, is the baseline against which every stranger case must be measured.

• 3. Deep In Prehistory

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  Australopithecus afarensis appears, in a 2010 study, to have eaten meat by carving animal carcasses with stone implements. That finding pushes the earliest known use of stone tools among hominins back to about 3.4 million years ago. Finds of actual tools date back at least 2.6 million years in Ethiopia, and one of the earliest distinguishable forms is the hand axe. Anthropologists treat tool use as an important step in the evolution of humankind. Because both humans and wild chimpanzees use tools extensively, the first routine use is widely assumed to predate the split between the two ape species. The earliest such tools were likely made of perishable sticks, or were unmodified stones impossible to tell apart from ordinary rocks. For a long time, weapons found in digs were the only early human tools studied and given importance. That has changed. Researchers now recognize tools for nutting, leatherworking, grain harvesting, and woodworking, including the category of flake stone tools. The old image of Man the hunter as the catalyst for change has been questioned too. Marks on bones at archaeological sites suggest pre-humans were often scavenging off other predators' carcasses rather than killing their own food.

• 4. Timeline Of Invention

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  Oldowan stone technology, scrapers used to butcher dead animals, appears around 2.5 million years ago. From there the inventory of human making expands in slow, staggered steps. Huts arrive about 2 million years ago, Acheulean hand axes about 1.6 million years ago, and the manipulation of fire possibly as early as 1.5 million years ago with Homo erectus. Boats follow at 900,000 years ago, cooking at 500,000, javelins at 400,000, and glue at 200,000. The bow and arrow emerges 70,000 to 60,000 years ago, with flutes and fishing nets both around 43,000 years ago. The later milestones cluster as societies settle. Brick was used for construction in the Middle East around 6000 BC, with agriculture, the plough, the wheel, and the gnomon all near 4000 BC. Writing systems arrive around 3500 BC, copper around 3200 BC, and bronze and salt around 2500 BC. Iron follows around 1500 BC, glass around 500 BC, and the stirrup in the first few centuries AD. Several of the six classic simple machines were invented in Mesopotamia. The wheel and axle first appeared with the potter's wheel in what is now Iraq during the 5th millennium BC, which led to the wheeled vehicle in the early 4th millennium BC.

• 5. The King And The Screw

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  The screw was the last of the simple machines to be invented, first appearing in Mesopotamia during the Neo-Assyrian period of 911 to 609 BC. Before it came the others. The lever drove the shadoof water-lifting device, the first crane machine, which appeared in Mesopotamia around 3000 BC and then in ancient Egyptian technology around 2000 BC. The earliest pulleys date to Mesopotamia in the early 2nd millennium BC. The Assyrian King Sennacherib, who ruled from 704 to 681 BC, claims to have invented automatic sluices. He also claims to have been the first to use water screw pumps weighing up to 30 tons, cast in two-part clay molds rather than by the lost wax process. The Jerwan Aqueduct, dated around 688 BC, was built with stone arches and lined with waterproof concrete. Water wheels and watermills appear later, in the ancient Near East in the 4th century BC, specifically in the Persian Empire before 350 BC across Mesopotamia and Persia. This use of water power was perhaps the first use of mechanical energy. The humble screwdriver, by contrast, was not invented until the late 15th century.

• 6. Tools That Make Tools

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  Machine tools occasioned a surge in producing new tools during the Industrial Revolution, and they trace their origins to the 18th-century instrument makers. Clock makers, watch makers, and scientific instrument makers developed them to batch-produce small mechanisms. Before machine tools, metal was worked by hand with hammers, files, scrapers, saws, and chisels, which kept the use of metal parts to a minimum. Pre-industrial machinery was built by a patchwork of crafters. Millwrights built water and windmills, carpenters made wooden framing, and smiths and turners made metal parts. Wooden components had a flaw. They changed dimensions with temperature and humidity, and their joints tended to rack, or work loose, over time. The demand for metal parts had a clear motive: precision. Precision allowed better working machinery, interchangeability of parts, and standardization of threaded fasteners such as machine screws, bolts, and nuts. Hand methods were laborious, costly, and imprecise, while machine tools enabled the economical production of interchangeable parts. The roster of machine tools runs long, from the broaching machine, drill press, and lathe to the milling machine, bandsaw, and grinding machines. Advocates of nanotechnology expect a similar surge as tools shrink to microscopic size.

• 7. Sorting By Function

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  Cutting and edge tools, like the knife, sickle, scythe, hatchet, and axe, are wedge-shaped implements that produce a shearing force along a narrow face. The edge must be harder than the material being cut, or the blade dulls. Even resilient tools need periodic sharpening, which removes deformation wear from the edge. Other categories sort the rest of the kit. Moving tools shift large and tiny items, many acting as levers that grant mechanical advantage; the hammer moves a nail, the maul moves a stake, and the screwdriver applies rotational force called torque. An anvil works in reverse, concentrating force by preventing a struck object from moving away. Further classes cover chemical change, like lighters and blowtorches, and guiding, measuring, and perception, like the ruler, glasses, square, microscope, and clock. Some tools defy a single box. An alarm-clock combines a measuring tool, the clock, with a perception tool, the alarm, and so falls outside every named category. The status of protective gear is debated, since items like gloves, safety glasses, ear defenders, and biohazard suits protect the worker rather than directly performing work. Tool substitution complicates the categories further. A car window roller could be replaced with pliers, and a Swiss Army knife stands as one of the earliest multi-tools, true to the saying that all tools can be used as hammers.

• 8. Beyond Human Hands

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  New Caledonian crows are among the only animals that create their own tools, manufacturing probes out of twigs, wood, and sometimes metal wire to catch or impale larvae. They are not alone in the broader phenomenon. Observation has confirmed tool use in monkeys, apes, elephants, several birds, and sea otters, though humans are now considered the only species that uses tools to make other tools. Chimpanzees have often been the subject of study, most famously by Jane Goodall, and Charles Darwin mentioned tool use in monkeys such as baboons in The Descent of Man. The range of animal tool use is striking. A group of dolphins in Shark Bay uses sea sponges to protect their beaks while foraging. Sea otters use rocks to dislodge abalone and break open shellfish, and carrion crows in Japan drop nuts in front of cars to crack them open. Octopuses use tools relatively frequently for invertebrates, gathering coconut shells for shelter or using rocks to create barriers. The word stretches further still, past the physical object. Vanessa Dye refers to tools of reflection for trainee teachers, quoting the French scientist Claude Bernard that we must change our ideas when they have served their purpose, as we change a blunt lancet. John M. Culkin captured the loop that this whole story circles back to when he said, we shape our tools and thereafter our tools shape us.