AROUND THE TURN OF THE 14TH CENTURY, ENGLAND’S KING EDWARD I led his soldiers north to battle Scottish rebels.
Eventually, he cornered his foes at Stirling Castle in central Scotland. Outside the castle walls, his English engineers built a phalanx of huge trebuchets. A trebuchet uses the force of gravity to fling projectiles. Its power comes from a counterweight—often a box that’s filled with stones or sand—connected to a lever arm. The other end of the arm is attached to a sling that holds a missile, such as a large rock. By raising the counterweight into the air with a pulley system and then letting it drop, the lever sends the boulder flying with great precision.
Denne historien er fra September - October 2016-utgaven av Popular Science.
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Denne historien er fra September - October 2016-utgaven av Popular Science.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
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They Might Be Giants
A photographer-and-ecologist team are on a mission to document the forests’ mightiest members.
Droplet Stoppers
Covid-19 made face masks a crucial part of every outfit, and we’re likely to don them in the future when we feel ill. Fortunately, there’s a style for every need.
Landing a Lifeline
For those whose livelihood depends on the ocean, a covid-spurred interruption in the seafood market might speed progress toward a more sustainable future—for them and for fish.
Headtrip – Your brain on video chat
Dating, Catching up with family, and going to happy hour are best in person.
Behind The Cover
Butterflies may seem delicate, but they are surprisingly tough.
Tales From the Field – A cold one on mars
Kellie Gerardi, bioastronautics researcher at the International Institute for Austronautical Science
The Needs Of The Few
Designing with the marginalized in mind can improve all of out lives.
Life On The Line
On the Western edge of Borneo, a novel conservation-minded health-care model could provide the world with a blueprint to stop next pandemic before it starts.
waste watchers
YOU CAN TURN FOOD SCRAPS INTO FERTILIZER IN ALMOST ANY CONTAINER. THESE BINS USE THEIR OWN METHODS TO ENCOURAGE THE PROCESS, BUT BOTH KEEP BUGS AND STINK AT BAY.
why can't i forget how to ride a bike?
LEARNING TO PEDAL IS NO EASY FEAT.
