The Roman Empire's onager catapult used torsion twisting an object, in this case a restraining rope or spring, by applying torque—to build tension in the arm and generate a powerful swing. The onager catapult was a central siege engine for the Romans from the 4th century A.D. until the 6th century, capable of launching projectiles over 400 feet to breach castle doors and walls. Our design can't quite do that, but it's perfect for kids to build and use in games and experiments. Building this catapult takes precise measurements, skill with a drill, and an understanding of how the pieces work together to launch a projectile (so read the instructions first). It's a fun, hands-on lesson in mechanical energy and torsion science!
BUILD A CATAPULT
MAKE THE CATAPULT FRAME
Drill four/16-inch pilot holes through the 10-inch frame pieces, with the holes 134 inches from each of the four ends and centered vertically. Drill a pilot hole into the center of each end of the crossmembers [1].
Apply glue to the ends of one crossmember and near the pilot holes on the inside of the 10-inch frame pieces; screw the crossmember into place [2]. Repeat this step on the other end.
Drill 3/16-and 1/4-inch holes through the sides of the frame, 5 inches and 5 1/2 inches on center, respectively, from the front of the frame. Glue the footings to the bottom of the frame, flush with the sides and 1 inch on center from the ends [3].
Drill pilot holes into the center of the ends of the footings; screw the wheels into place [4].
INSTALL THE UPRIGHTS AND UPRIGHT SUPPORTS
Esta historia es de la edición May - June 2022 de Popular Mechanics.
Comience su prueba gratuita de Magzter GOLD de 7 días para acceder a miles de historias premium seleccionadas y a más de 9,000 revistas y periódicos.
Ya eres suscriptor ? Conectar
Esta historia es de la edición May - June 2022 de Popular Mechanics.
Comience su prueba gratuita de Magzter GOLD de 7 días para acceder a miles de historias premium seleccionadas y a más de 9,000 revistas y periódicos.
Ya eres suscriptor? Conectar
Whether We Live in a Simulation - scientist Melvin Vopson, PhD, studies this exact thing- the possibility that the universe might indeed be a digital facsimile. And he claims to have evidence.
In the 1999 film the Matrix, Neo discovers A truth to end all truths-the universe is a simulation. While this premise provides fantastic sci-fi fodder, the idea isn't quite as relegated to the fiction section as one might expect. . In fact, University of Portsmouth scientist Melvin Vopson, PhD, studies this exact thing- the possibility that the universe might indeed be a digital facsimile. And he claims to have evidence.
The Ancient Language of Easter Island - Today, humans inhabit- or have, at the very least, explored- pretty much every corner of the planet. But that immense proliferation of Homo sapiens across the globe was a slow process.
With the first humans leaving Africa between 60,000 and 120,000 years ago, the species slowly spread across the Earth over many millennia. And one of the last places these ancient humans made their way to was the southeastern Pacific island of Rapa Nui, known more broadly as Easter Island.Located 2,360 miles off the coast of Chile, Rapa Nui is one of the most isolated places in the world. Its native people, who are also named the Rapa Nui, first arrived on the island's shores between A.D. 1150 and 1280, and lived in isolation until the arrival of Dutch navigator Jacob Roggeveen in 1722.
Underwater UFOs - A retired U.S. Navy admiral believes that the government should look to the oceans to help solve a mystery in the skies.
A retired U.S. Navy admiral believes that the government should look to the oceans to help solve a mystery in the skies. Rear Admiral Timothy Gallaudet, former Oceanographer of the U.S. Navy, recently published a paper arguing that unidentified anomalous phenomena (UAP, more commonly referred to as UFO) and unidentified submersible objects (USO) are linked, and should be studied further.
Synching Up Our Circadian Rhythms - If you've ever done any kind of long-distance travel, or just woken up feeling under-rested thanks to daylight saving time, you know how important your circadian clock is.
If you've ever done any kind of long-distance travel, or just woken up feeling under-rested thanks to daylight saving time, you know how important your circadian clock is. Like many things in your body, your circadian rhythm is more complicated than it might seem on the surface. Rather than being entirely brain-based, it's actually controlled by a collection of several circadian clocks (central and peripheral) that all work together to keep your gears turning like a well-oiled machine.
SKINWALKER RANCH REVEALED
The 512-acre ranch has captivated real-estate tycoons, TV producers, and the U.S. government. What are they searching for?
Upgrade Your Living Room With This DIY - MID-CENTURY COFFEE TABLE
This project is easy to build and customize to fit your space.
CHASING AN ASTEROID
HOW NASA DEFIED INCREDIBLE ODDS TO GET ITS ASTEROIDHUNTING OSIRIS-REX MISSION OFF THE GROUND AND IN THE PROCESS UPENDED WHAT WE KNOW ABOUT OUR SOLAR SYSTEM.
INDISPENSABLE LESSONS FROM A POP MECH LEGEND
With people moving around so much these days, it's perfectly natural to wonder how an editor can just come along and stick like a barnacle to the hull of Popular Mechanics, lasting for 35 years.
SAVING THE SUGAR BUSH
A technological revolution has transformed the ancient tradition of sugar making-with big implications for local economies and ecosystems imperiled by climate change.
MANIPULATION AND MEDICAL ETHICS
The taking of cervical samples wasn't the only medical procedure of dubious consent in Lacks's story.