Primitive Technology / Intuitive Physics – Atlatl

Comment: Interest in the atlatl has been revived by the growing “primitive hunting technology community” which is related to the “off-grid” survival movement which embraces sustainable methods for procuring food without dependence on high-tech weapons.

As kids, most of us were briefly introduced to the atlatl in social studies class, as part of “Human Cultural History” – a thin survey about technical progress and foods, farming, the advent of cities and the titanic architecture of famous ancient empires.

The atlatl stuck out like a sore thumb: stone, wood and mud construction seemed to be pretty obvious steps for humans to “figure out”, but how did someone “come up with” the spear-launcher, which in my child mind appeared to be a much more sophisticated invention, and a leap into a future of human innovation. My father was an engineer, so  I was aware of the mathematics, tables, slide-rule calculations and testing and revision required for him to design mechanical gadgets and components; so how did “cave men” create weapons and tools, without these technical advantages? It’s a question that to this day produces varied explanations and arguments (many preposterous) that deal with the fundamental concept of “being and becoming” human.

Of course, I have my opinions, based in “visual thinking” as the capable manipulation of “intuitive physics” without formal math and theory-based brain processing.


Missouri Hunter Harvests 15-point Buck with Atlatl

Predating the bow and arrow, atlatls are one of the oldest primitive weapons still in use. The dart (a 4′-6′ projectile, much like an arrow) is placed on a launcher—the atlatl itself—that has a socket at the rear to temporarily hold the dart. The hunter propels the launcher forward and the dart flies like a spear. The atlatl allows the dart to be thrown much faster than what could be achieved by hand, and launched darts could go as fast as 100 miles per hour.



Contemporary atlatls by Jim Fisher

How Joints Use Leverage (And Why That’s Awesome) June 28, 2013 by chuck

atlatl: (link to Wikipedia)


Specifically, the handle in which the spear is cupped is an atlatl. Humans have been using devices like this for hunting and warfare for around 30,000 years. “Atlatl” is the Aztec terminology, but it has been called “amentum” by the Romans; “woomera” by Australian Aborigines, and  “ankule” by the Greeks.


Let’s be clear: it’s essentially a stick. But this stick, employed just so, dramatically increases the power and accuracy of a projectile. Modern versions made of carbon fiber and aluminum, can launch a spear 850 feet. By comparison, the record distance for the javelin throw is 321 feet.

Those extra 529 feet can be accounted for through the beauty and elegance of Sir Isaac Newton’s Laws of Motion. A  throwing spear has a metal or stone tip, shaped and sharpened to cut and pierce. This shaped point, by virtue of its material, is more massive (m) than the butt-end of the spear. Consequently, the same force (F) applied to both ends would cause the butt-end to accelerate (a) faster. F=ma, says Newton.

Picture this: a swing of the atlatl causes the butt-end of the spear to accelerate. The more-massive pointy end resists acceleration, building speed more slowly than the less-massive butt-end. With the back end moving faster than the front, the spear bows. (flexes to become an arc shape)

That bowing action (flex) converts the kinetic energy of the swing into potential energy stored in the tensile fibers of the spear’s shaft. At the last moment of contact between spear and spear thrower, the shaft unbows, (straightens) converting its stored, potential energy back to kinetic energy, and adding it to the overall acceleration of the spear.

It’s just a stick! How did humans 20,000 years before the invention of agriculture come up with such an ingenious little device?

Most of the joints in the body “exploit” the same principle of physics.

Did anyone happen to notice the Greek term for these spear throwers? Ankule. If you’re thinking that sounds suspiciously like ankle, you’re right, and it’s not an accident. Most of the force that accelerates your running stride is “free energy” due to simple physics (levers) – the arrangement of “bone sticks” that make up your skeleton.



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