In this lesson, selected segments from the PBS series The Human Spark are used to help students understand both the construction and context of some of the prehistoric tools which allowed early humans to survive and thrive. Particular attention is paid to the design and use of these early tools, the specific techniques used in their construction, and the reciprocal relationship between human technology and human evolution.
In the Introductory Activity, students will review the six simple machines and their role as the building blocks of most technologies. The Learning Activities will examine the progressively more sophisticated stone-age technologies of the hand-ax, the spear, and the atlatl assisted spear. The Culminating Activity asks students to brainstorm other tools and technologies which have affected the course of human development, and to conduct further research into them.
This lesson is best used as an introduction to a unit on the history of technology, or as a supplement to an anthropology or archaeology unit about Neanderthals and/or early humans.
Students will be able to:
- Describe the six simple machines and give examples of each
- Describe detailed construction techniques for several different prehistoric tools
- Distinguish between natural and man-made wear patterns on rocks.
- Discuss how certain tools and technology have advanced human development and may have affected human biological evolution
Three 45-minute class periods
If It Ain't Broke Video
To Make a Spear Video
Please note: The following two videos are found on the Human Spark website. They are NOT downloadable.
A website from the Center of Science and Industry featuring animatedinteractives about the nature and applications of simple machines.
For the teacher:
- A computer with internet access connected to a projector and speakers for classroom use.
Part I: Introductory Activity
1. Ask students how they would define “technology” in the most simple and general terms possible. (Accept all answers, but explain that anthropologists define technology as the use and knowledge of tools, techniques, and systems tosolve problems or otherwise serve some purpose.) Ask students how they would define a tool in the most simple and general terms possible. (Accept all answers, but explain that a simple working definition of a tool is that it is somesort of instrument used to perform or facilitate work.) According to thisdefinition, ask students if they think something as complex as a computer couldbe considered a tool. (Yes.) What about the software that runs on that computer? (Yes.)But what were the tools that made these tools, and what in turn were the tools used to make them? Where does it end? Ask students to come up with a list of 10 of the simplest tools they can think of. In other words, 10 of the most physically useful objects which they think cannot be broken down into even simpler useful objects. (Probable answers include a knife, a hammer, a screwdriver, etc.) Write all answers on a blackboard or whiteboard.
2. Log on to the “Simple Machines” website.Click on “The Essence Of Simple Machines” tab on the bottom left of the screen. The screen will show images of the six classic simple machines. Ask the class to identify and explain the basic function of each one, clicking on themachine’s link to get more information if necessary. (Pulley, inclined plane, lever, screw, wedge, and wheel.)
3. For each tool on their list of 10 simple tools, ask students if it is, or contains,one or more of the six simple machines. (E.g.a knife would be an example of a wedge; a hammer would be example of a lever.)
4. Explain that these simple machines do indeed constitute some of humanity’s earliest tools—developed and used long before they were named or recognized as the basic building blocks of future technologies. Tell students that in this lesson they will be taking a closer look at some specific instances of “stone age technology,” exploring how some of humanity’s earliest tools were created, what they were used for, and what further evolutions and advancements in humanity itself they may have sparked.
Part II: Learning Activity
1. Tell students that in this lesson they will be watching some segments from the PBS series The Human Spark, which explores different theories about what it is that makes humans unique among animals. Ask students what ideas they may have about what makes us unique? (Accept all answers.)Ask students if they think that making and using tools are traits unique tohumans? (Accept all answers.) Explain that while tool making and use was once considered uniquely human, more recent research has revealed that other species also make and use tools. Chimpanzees, for example, have been observed stripping sticks with their fingers and teeth so that they may more easily be inserted into ant and termite nests as probes to collect the edible inhabitants. Nevertheless, for no other species has tool making and use—on other words, technology—been such a central part of an evolutionary strategy as it has been for humans.
2. Tell students that they will now be looking at a video segment which examines the context and construction of one of humanities’ earliest tools—the hand ax. As they watch, ask students to watch for the reason why archaeologist John Shea believes the design of the hand ax changed so little for so long. Play If It Ain't Broke.
3. Review the focus question: why does archaeologist John Shea believe the design of the hand ax changed so little for so long? (The design of the hand ax was not under a “powerful pressure of natural selection” to evolve and improve; in other words, it wasn’t broke, so it wasn’t fixed!) Ask what natural selection is? (Charles Darwin’s principle of “survivalof the fittest.”) Explain that Shea is using an evolutionary term usuallyapplied to organisms and applying it instead to an organism’s inanimatecreation; the more “fit” a tool seems to serve its purpose, the less it isrefined or “evolves”, and the more it “survives” in its existing form.
4. Ask students how stone-age hand axes were made, based on Professor Shea’s demonstration. (A piece of rock is with another piece of rock, which chips pieces off, creating a sharp edge.)What kind of rock would work best for constructing hand axes in this manner? (Accept all answers, but point out that flint and certain other sedimentary rocks are ideal.) What are sedimentary rocks? (Sedimentary rocks are created by the geological compression over time of layer upon layer of sediments, generallyleft behind where there were once rivers or other bodies of water.) Why arethey ideal materials for creating tools? (Their sedimentary layers can easily be chipped or “flaked” away to produce a sharp edge.)
5. Tell students that besides being a good stone for making into blades, flintpossesses another extremely useful quality—what is it? (Flint, when struck with a rock containing iron, can generate sparks which can be kindled into flame.) Explain that this technique, known as “percussion firestarting,” is generally thought to have developed around 7,000 B.C.—much later than the stone hand axes seen in the previous clip. Recent archaeological discoveries, however, suggest that fire did indeed play a role in the creation of certain stone blades dating back at least 72,000 years ago. As they watch the next clip, have students pay attention to what “silcrete” is and what role fire played in its use as a rawmaterial for stone blades. Play Pyroengineering.
6. Review the previous question: what is silcrete? (Amaterial long thought to be ideal for making stone blades, many high-quality examples of which have been found by archaeologists). How was archaeologists’ actual experimental experience with silcrete problematizing this theory? (They themselves couldn’t make silcrete into good blades.) What was the archaeologists’ breakthrough in understanding how the high-quality silcrete blades were made? (They discovered silcrete encased in ash, suggesting that it had been heat-treated.) What happened when they heat-treated silcrete themselves during a barbeque? (It took on the same red color as the original silcrete blades they’d found, and when struck, flaked off sharp edges beautifully.)
7. Tell students that hardening by fire is also known as “tempering,” and that it is widely used in almost every type of manufacturing today, but that silcrete was perhaps its original use. Ask student how this type of “pyroengineering” might first have been discovered by early man? (Accept all answers, but point out that it may very well have been discovered accidentally when raw silcrete was heated in a cooking fire not unlike that made by Curtis Marean and his fellow archaeologists at their barbeque.) Remind students that silcrete blades have been found that date back over 72,000 years. Ask students how they think tempering would have been possible so many years before humans developed the ability to create fire? If necessary, offer this hint: how does fire occur naturally? (Flames started naturally by lighting strikes could, with care, be maintained more or less indefinitely.)
8. Point out how the case of silcrete is a good illustration of how much archaeological knowledge must be extrapolated from relatively mundane artifacts (e.g. an ash-encrusted rock) and confirmed through modern experimentation (e.g. the archaeologists’ barbeque.) When most of the prehistoric archeological record consists of various types of rock, even the subtlest differences can besignificant to the trained eye. Ask students how archaeologists can distinguishbetween pieces of flint which were simply broken naturally from pieces thatwere deliberately fashioned into axes by early humans? (Accept all answers, and tell students to think about this question as they watch the next clip.) Play Making Stone Tools is Sooo Millions of Years Ago.
9. Pause right after John Shea says to Alan Alda “Of course theydidn’t have guns yet.” Review the previous question: how can archaeologistsdistinguish between pieces of rock which were naturally broken from pieces thatwere deliberately fashioned into axes by early humans? (Rocks that are naturally fractured tend to be worn equally over their entire surface, and chipped in all directions, whereas artificially created ax heads show careful chipping only along the cutting edges, and always in one direction. Also, the environmental context in which rocks were found gives strong indication of whether they were made by humans.) Ask students what specific uses they think hand-axes had. Play "Making Stone Tools is Sooo Millions of Years Ago" through to the end.
10.Review the previous question: for what specific uses were hand-axes used? (They were multi-use tools, but depending on the nature of the edge they could be used for cutting or scraping.) Ask students to review the six classic simple machines. (Screw, inclined plane, pulley, wheel, lever, and wedge.) What kind of simple machine is a hand axe? (A wedge.)How does a wedge work? (It splits objects.)
11. Ask what would happen if you somehow attached a hand axe to a long stick or shaft? (You would have created a spear.) What are the advantages of a spear over a hand axe? (Greater range.) Ask if a spear is fundamentally a different type of simple machine than a hand axe. (No—a spearhead is a wedge exactly like a hand-axe; only the nature of the force behind it is different—i.e. the force of a thrust, or the force of momentum if thrown.) Ask students how they think early humans went about making spears. (Accept all answers.) Tell students to be watching in the next clip for the answer to this question. Play To Make a Spear.
12. Pause after Shea says “In a real one we’d have a lot of glue in there.” Review the previous question: how did early humans make multi-part spears? (A stone spearhead would be made in a mannersimilar to a hand ax, inserted into a groove cut in a wooden stick or shaft,held in place with pitch or some other type of glue, and secured by multiplewindings of animal sinew or plant fiber.) Explain that the spear, whenthrown, was one of the earliest examples of “projectile technology.” Ask whatthe very earliest example probably was? (Athrown rock.) Ask students what advantage projectile weapons had against the hand-held variety? (Greater range.) What are the benefits ofa weapon with greater range? (Accept all answers.) Have students pay particular attention to this question as they watch the remainder of the clip. Play To Make a Spearthrough to the end.
13. Review the previous question: what are the benefits of a weapon with greater range? (Larger, more dangerous prey like woolly mammoths could be hunted at a safer distance.) Ask students if in the last clip they observed Shea and Alda using another example of stone-age technology to give their spears even greater range? If necessary, go back and play the clip from the previous pause point. (They were using wooden “spear-throwers,” one end of which fit over the spear’s end with the other being held in the hand of the thrower.) Ask students how they think a spear-thrower works. (Accept all answers.) Tell students that the spear thrower used byShea and Alda—also known as an “atlatl”—has been developed by many primitivecultures around the world. Ask students if they think the atlatl is an exampleof another simple machine? (Yes—a lever.) Explain that an atlatl isspecifically a “third class lever,” which works by applying force between thefulcrum (the thrower’s shoulder) and the load (the spear or dart). By allowinga smaller movement on the fulcrum end of the lever to be magnified into alarger movement on the load end, an atlatl adds speed—and accordingly, distance—to the spear’s trajectory by effectively lengthening the thrower’s arm.
14. Ask students whether early humans hunted larger game animals individually or in groups? (In groups.) Why? (Because even the more advanced projectile technology of the atlatl-thrown spear wasn’t powerful enough for one person to kill a larger animal single-handedly.) Ask students why John Shea suggests in the clip that the nature of cooperative hunting was in itself also a major factor in humans’ evolutionary advancement. (The coordination and cooperation necessary for a group of early humans together required communication and planning, which in turn required language.)
15. Ask students which they think came first—primitive hunting implements or the language necessary to coordinate their use? (Accept all answers.) Point out that the likely answer to this “chicken and egg” dilemma is that thedevelopment of hunting tools and language was intertwined, with an advance inone leading to an advance in the other. Ask how else improvements in huntingmight have affected human evolution? (Acceptall answers.) Explain that, generally speaking, improvements in huntingallowed more and bigger game to be hunted, providing more meat in the diets of early humans; more meat, in turn, is believed to have contributed to a larger brainsize; a larger brain size, among other things, helped contribute to even moresophisticated tool technology and language use, and so on. Essentially, ourtools are extensions of ourselves—technologies that are both the artifacts ofour evolutionary development to date, and catalysts for future development.
Part III: Culminating Activity
1. Divide students into groups of 4-5. Allow 20-30 minutes for groups to brainstorm five other basic tools or technologies which they think may have contributed to human advancement. Instruct groups to keep their ideas as simple and elemental as possible (e.g. “the plow,” rather than “farming machinery”).
2. Have each group present their ideas to the rest of the class as you write down all ideas on the blackboard or whiteboard. Encourage questions and comments from the class. Can any tool or technology be reduced to a simpler, more basic element? Is the tool an example of a simple machine? Does it include multiple simple machines? What human advancement might it have helped facilitate?
3. After all groups have presented, have each student choose one of the tools or technologies listed on the black or whiteboard as the subject for a short research essay addressing the following questions:
- When was the tool or technology developed/invented?
- What need did it address?
- Who developed/invented it?
- What advance did it make possible?
- How has the tool or technology been developed, improved, or expanded beyond its originalincarnation?