On August 20th, 2017 we learned about

Ancient Romans special regard for eating jar-raised rodents

For all of the foodie-themed photos people share today, the world somehow lacks gratuitous shots of dormice being served for lunch. This seems like a missed opportunity, because edible dormice were one of the original foods to brag about, with scholars and elites writing down details about how the rodents were served in lieu of selfies and filtered photos. Like the particular interests of gourmands today, this interest wasn’t because edible dormice were a staple of the ancient Roman diet, or because they were necessarily that much tastier than any other roasted mammal. Serving up dormice was a way for hosts to dazzle their guests without making a huge investment in the process.

From pot to plate

A serving of edible dormouse (Glis glis) might include honey, poppy-seeds, pepper and bits of pork. The layered flavors alone would have been impressive to a Roman audience, as more modest meals would have been heavy on salted meat or fish, as the salt was a critical preservative for less-than-fresh foods. Dormice, on the other hand, didn’t need the space or resources a pig did, and they could be raised in a villa without much fuss. The animal was placed in a ceramic pot called a gliarium, where it was fed and watered until it was ready to be eaten. With small air holes and just enough room to move around, a dormouse didn’t have much to do besides sleep and fatten up.

Once it was time to eat, the fact that dormice weren’t actually difficult to raise didn’t seem to matter much. They were apparently valued enough that supplying them could be a profitable enterprise, but not really enough to amount to more than an appetizer. Like exotic foods of today, people made notes about eating a dormouse, particularly its size as testament to the host’s wealth, but their relative scarcity clearly helped make them more intriguing than your average squirrel or rat.

Dormice in decline

Dormice aren’t on many menus anymore, but their may still be in trouble. Hazel dormice (Muscardinus avellanarius) in England are in decline, with populations dropping 70 percent in 20 years. As their absence on Instagram proves, this decline isn’t due people making them into fancy appetizers again, but larger environmental problems. Habitat loss, climate change and local woodland management are all suspected to play a role in shrinking dormouse populations in England.

Source: Dormice, ostrich meat and fresh fish: the surprising foods eaten in ancient Rome by Emma Mason, History Extra

On August 16th, 2017 we learned about

Reasons we regard Route 66 as a historic roadway

This summer, my third-grader went on a road trip with her grandmother and cousin to the Grand Canyon. During the hours of driving, the kids saw more and more signs not for the Grand Canyon, Petrified Forest or Meteor Crater, but for some mysterious entity known as Historic Route 66. It seemed to be all around them, with stretches of roadways and stores all claiming some kind of connection to whatever this 66 thing was. Hearing it was the name of a road helped a little bit, but with no yellow bricks, roadside bells or anything relating to 66, the significance of Route 66 is easy to miss, especially today.

A very particular path

The first major roadway to stretch across the continental United States was the Lincoln Highway. The road opened in 1913, enabling a relatively quick drive from Times Square in New York City to Lincoln Park in San Francisco. One road was obviously not going to be enough to satisfy the growing car and truck traffic in the United States, and legislation was introduced in 1916 to build comprehensive highway system across the country. It took ten years for those plans to come to fruition, and in 1926 Route 66 opened as one of the first new roads to allow more convenient travel from the Midwest to the west coast.

The convenience of Route 66 was a carefully nuanced balance though. On one hand, by heading southwest from Chicago across largely flat territory, cargo trucks had an easier route to California than the sometimes snowy Lincoln Highway could provide. On the other hand, the road was purposely not a straight shot to the Pacific Ocean. Planners wanted the road to meander a bit, allowing it to link hundreds of small communities that had no other major roadways to get to bigger cities. Farmers thus had an easier time transporting their goods, boosting many small economies all along the route.

From “The Mother Road” to roadside attractions

Route 66 took on some unintended significance early on as well. Laborers were employed during the Great Depression to help pave sections of road. The Dust Bowl in Oklahoma sent as many as 210,000 people to California, many of which traveled on Route 66. This significance was memorialized in John Steinbeck’s The Grapes of Wrath, marking Route 66 as “The Mother Road” in people’s minds even if they’d never driven on it themselves. Finally, as World War II loomed on the horizon, Dwight D. Eisenhower was impressed with the utility of this kind of reliable infrastructure from a military perspective, an idea he would eventually carry with him to the White House.

After World War II, Route 66 was reborn again. Instead of a necessary path for commerce, migration or commerce, tourists started flocking to the American southwest. Nat King Cole’s rendition of “Route 66” was nearly an ad jingle for tourism throughout the Chicago to Los Angeles corridor, and many businesses started directly catering to these travelers’ interests. Motels grew out of auto camps, diners and gas stations proliferated, and many odd roadside attractions were designed to catch people’s eye as much as the natural landscape could. Many of these sights are still around, now with some historical significance layered on top of their already striking appearances.

Facing the four-lane future

As my third-grader found out though, its possible to miss some of this if you don’t know what you’re looking for. This is partly due to the inevitable physical decline of the actual roadway along Route 66, spurred by it’s obsolescence as an arterial route. In 1956, then President Eisenhower signed the Federal Aid Highway Act, kicking off construction of a huge network of major highways. Unlike the meandering path of Route 66, highways like I-40 were somewhat modeled after Germany’s autobahn so that travel could be safe and efficient at higher speeds. Rather than stop in each town along the way, highways now let people zip from one destination to the next with minimal interactions along the way.

It took some time, but in 1970 four-lane roads finally allowed travelers to “skip” any portion of the original Route 66. Nobody is about to argue that Route 66 can compete on the grounds of efficiency, but there are efforts to preserve the experience, particularly the post-war tourism, as a cultural milestone in America.

Source: The History of Route 66, National Historic Route 66

On July 26th, 2017 we learned about

Learning about train wheels through the lens of Thomas the Tank engine

We all pretty much “get” wheels, right? From the time we’re babies, we see wheeled objects rolling around us on a regular basis, and it’s not long before the functionality of a wheel and axle can be taken for granted as just another part of almost every vehicle out there. So when my four-year-old recently looked up from his heap of toy trains and wooden track to ask about a particular wheel on a particular train, I had to admit that I really didn’t have an answer. The train in question is known to Thomas the Tank Engine fans as “Emily,” and she stands out among her peers with an oversized wheel each side of her boiler, rather than the more common set of small wheels under the locomotive. Fortunately, behind the expressive faces and somewhat snarky attitudes found on Thomas characters, there is some factual basis for many of the engines, and in this case Emily’s giant wheel does indeed have an explanation.

Which wheels provide power?

To make sense of how this character’s design connects with real life engineering, it’s helpful to embrace your inner four-year-old and familiarize yourself with how train wheels work. Locomotives generally have a battery of wheels, but like a two-wheel drive car, only a few wheels are actually being driven by the engine, appropriately called the driving wheels. The other wheels are there to distribute the weight of the locomotive, and stabilize it as it moves down the track. Wheels in front of the drive wheels are the “leading truck” and those behind the drive wheels are the “trailing truck.” Drive wheels could then be coupled together with the coupling rods you often see on the outside of train wheels, joining them together to share and distribute the power from the engine.

Emily’s enormous wheel

So where does that leave our giant mystery wheel on Emily? Emily appears to be based on a class of steam locomotive called a Great Northern Railway (GNR) No. 1 Stirling Single. The important bit of all that is the “Single,” as it refers to the single, gigantic drive wheel on the side of the locomotive, which received all the power from the engine via a large piston on the outside of the wheel. This design was put into service in 1870, and was a way to balance concerns about speed versus stress on the axle. The record-holding 96-inch wheel could move the train along at a good speed while not needing to rotate as fast as a small wheel would. The catch is that a large drive wheel is slower to accelerate, and only goes fast once it’s had time to get moving. These factors made for a train well-suited for express trips between York and London, generally traveling around 50 miles per hour.

Gordon goes faster

At this point, Thomas the Tank Engine fans might be pointing out that Emily is not in charge of the express trains, as that’s Gordon’s job. Conveniently, Gordon is also based on a real locomotive, the London and North Eastern Railway Gresley A1. These locomotives were first built in 1922, and had six drive wheels to get them moving. They were heavy but powerful, and engineering improvements would eventually get them up to 108 miles per hour over short distances. It’s not clear on my son’s toys, but the drive wheels on this locomotive were all 72 inches in diameter, making them only slightly smaller than what was found on a Stirling Single. The wheels just have a harder time standing out when proportioned on a 70-foot-long locomotive.

Thomas’ torque

While Thomas himself was never referred to as being especially huge or fast, it’s worth noting the utility of this cheeky little engine as well. Thomas was based on the London, Brighton and South Coast Railway’s A1 Class locomotive, often referred to as “Terriers.” These tank engines were often used to shunt cars around freight yards, and had excellent acceleration thanks to their six smaller drive wheels. When not using their torque to push other cars, they were used on branch lines since they could get up to speed quickly between stations, completing routes on tight timetables, just like in the children’s books.

The accuracy of these trains isn’t an accident, as The Railway Series was created by a family of train enthusiasts. Wibert Vere Awdry worked primarily as a clergyman, but he also worked for years on England’s Steam Railway Heritage. Christopher Awdry, the son who Wilbert invented Thomas for, also worked with trains, volunteering on the Talyllyn Railway in Whales between writing more Thomas stories. I don’t recall any stories about Emily winning long-distance races, but clearly there was an appreciation for engineering got these engines moving.

Source: Steam Engine Wheel Arrangements, H2G2

On July 13th, 2017 we learned about

Searching for the start of teeter-totters, tilt boards and seesaws

My four-year-old is currently a big fan of the seesaw. Or is it the teetter-totter? The tilt board? There are many names for this piece of playground equipment, all of which refer to what’s essentially a lever. Levers as machines let us do a lot of otherwise difficult work, although in the case of most playgrounds, the perfectly symmetrical arrangement of a seesaw actually makes things a bit tricky for a large adult and a small child. I do extra work to avoid launching my child thanks to our equal distance from the fulcrum, although there’s a chance that bit of physics is what got seesaws started in the first place.

Korean catapult

With something as fundamental as a lever, it’s not easy to pin down the first time anyone decided they were fun to sit on. One line of thinking connects modern seesaws to 널뛰기, or neolttwigi, a device from Korea that dates back at least a few hundred years. A neolttwigi is like a low seesaw intended to launch someone in the air. One person jumps onto the empty side to boost their playmate straight up. The story is that this device was first developed so that young women could boost each other high enough to see over the walls surrounding their homes, although since then acrobatics and props like jump-ropes have been added to the mix.

Teetering, tilting and trembling

The various names for a seesaw may hold clues as well. Americans supposedly prefer the term “teeter-totter,” although those terms existed separately before being brought to the playground. Teeter is related to titter, which probably comes from an Old Norse word titra, which meant “to shake, shiver, totter or tremble,” which seems fairly appropriate. However, those definitions are fairly broad, which doesn’t help describe the exact device in question. French terms like balançoire only mean to balance, although the theory that seesaw is a bastardization of ci-ça (see-saw), which means “this-that” is at least more playful.

Syncing saws

The most specific connections are based around the name seesaw and how it intersects with hard labor. Before engines sped everything up, sawyers were people who sawed logs and trees. For bigger jobs, two men would hold handles on either side of a large saw, lunging back and forth in an even rhythm to efficiently cut through the wood. Another variation was the pit-saw, where one sawyer was elevated above the other, sawing down at an angle. In either case, the work went better if the back-and-forth motion remained in sync, and so sawyers would sing or chant to coordinate their movement.

These songs introduced the term “see-saw” not for a specific meaning as much for rhythm. They turn up in print in the 1630s with phrases like “see-saw-sack a down” and eventually “See Saw, sacaradown, / Which is the way to London town?” in 1685. Playing on levers probably predates these chants, but the name seesaw made it to the playground by 1704. Kids may have been pretending to be sawyers, chanting along as they rocked up-and-down. While we’re not as familiar with two-man saws today, at the time it was probably a very descriptive term, especially compared to “equidistant class one lever.”

Source: See-saw by Michael Quinion, World Wide Words

On June 28th, 2017 we learned about

A brief history of ships sharing statements by hoisting and waving signal flags

Even though we like to romantically think of the ocean as a serene, relaxing place, it’s actually pretty noisy. Between the wind and waves, anyone talking on the deck of a ship is competing with around 85 decibels of splashing and spraying, which is close to the equivalent of a standing 100 feet away from a 45-mile-per-hour diesel locomotive. You could probably raise your voice enough to talk to someone next to you, but since Ancient Greece people have been trying to come up with ways to communicate between different ships at sea. This was often to coordinate military action, but today includes a variety of statements that might need sharing over moderate distances when speaking isn’t an option.

Hoisting preset signals

Sound can travel pretty far through the air, but from the deck of a ship it can’t really compete with light. To compromise, ancient naval commanders would hoist special flags above their ships that signaled to others that it was time to come over and speak face to face. This obviously has some scheduling limitations, and so people tried putting more information into the flags themselves. Different colors, shapes and positioning was used to build up a vocabulary of commands that could be posted so that other ships could view them from larger distances, whenever their view was clear.

Eventually the details of reading these flags evolved into more elaborate codes, complete with numbers, letters and ways to make substitutions if your available flags didn’t include two copies of a certain signal. Using what amounted to three sets of flags, a ship could basically broadcast around 1,000 different signals. In many systems, any message that didn’t have a dedicated flag combination could just be spelled out, letter by letter. There have been many revisions of these systems, some peaking at 70,000 possible signals, but today things have been simplified a bit. The current International Maritime signal-flag vocabulary can still use combinations of flags, but many of the most commonly used messages can be shared as a single flag for convenience. These include important messages like “I have a doctor on board,” or “I am taking on or discharging explosives.”

Sharing with semaphore

Like all forms of technology, there’s never been a single standard for flag-based communication. In the seventeenth century, Robert Hooke started designing the precursor to semaphore flags, which didn’t actually involve the ocean at all. Semaphore towers were tall buildings set as far as 150 miles apart, each with a pivoting crossbar on top. Each end of the crossbar was fitted with an extension that could be arranged to make the entire shape resemble, a line, an “S”, an “L”, or more. Arranging the angles of these bars allowed for 196 distinct positions, each corresponding to a character that could be seen from a great distance. The system allowed for thousands of signals to be sent faster than a horse could deliver a message.

The towers were successful for many years, even delaying the initial adoption of telegraph wires in France. However, they found a more permanent home on board ships, where the crossbars and beams could be replaced by a human holding two red and yellow flags. By adopting different poses with one’s arms, a message could be sent fairly quickly, although it needed to be seen at the right moment, since nobody wanted to be standing on deck waving flags all day long.

Flags, lights and voices

Flags still have their place on ships today, but they do face a lot of competition. Flashing lights signaling Morse code were one earlier alternative to flags, with the big advantage of being visible at night, and maybe even in poor weather conditions like rain. From a military standpoint, radio transmissions are superior to all of the above, since flags and light beacons are not only visible to your own crews, but to nearby enemies as well. Codes could be used to make things more opaque, but being able to communicate directly with your voice is now a much faster, detailed way to say “hi” when out on the water.

Source: Signaling at Sea by Joseph McMillan, Sea Flags

On June 15th, 2017 we learned about

The 19th century reasoning for why your young students stay home all summer

I can still remember the feeling of excitement and relief as a school year ended. Classrooms were dismantled, work was taken home, and schedules and obligations started to fray in a delightful warm-up to summer vacation. I have to remind myself of these feelings, because as I witness my daughter wrap up second grade, things feel very different from my perspective. How is my kid this old already? What will happen with her friendships over the summer? What’s she going to do all summer Why is summer vacation even a thing?!

Where and when class was in session

One of the long-standing myths about summer vacation in the United States is that it was borne out of the same agrarian thinking that gave us other antiquated mistakes, like elections being held on Tuesdays. Kids never needed summers off to go help on the farm, and in rural communities the school year was actually limited to summers and winters. That way, the whole family would be available when it counted— spring and fall. It was a shorter school year overall, but it theoretically got the job done, especially for folks planning sticking with farming as they grew up.

Kids in urban areas didn’t have this pressure, and so technically they could enjoy free childcare, er, education, 248 days a year. However, attendance wasn’t mandatory, and kids would miss random portions of the curriculum as result. Summertime added a bit of additional discomfort, thanks to the way cities trap and hold heat. In the 19th century, families with the means to travel would take the kids out of town to flee the heat, although overall attendance wasn’t much worse than other times of year. Still, the inconsistency led to some school years being reduced by arbitrary amounts.

Standardizing the two schedules

So what was the motivation for our current schedule? There was talk about giving urban students’ brains a rest, while also looking for a way to beef up supposedly weakened physiques. Rural kids supposedly needed to work their brains more regularly, setting up an arrangement where both schedules could meet in the middle. More concretely, there was a desire to standardize the school year, and so districts targeted 180 days of school, with a big break in the middle when school houses were hot. This was complemented by emerging eight-hour workdays that meant that leisure time around the family wasn’t going to be so hard to come by. Since then, summer vacation has been praised as a block of time that can be potentially unstructured, or just the opposite- a chance to take on entry-level jobs before really entering the workforce.

This schedule is of course, not universal. Other countries around the world often keep kids in school more regularly, with moderate breaks between each seasonal quarter. This is often praised by teachers, because a few months away from the classroom seems to cost kids educational progress. Without academic reinforcement, taking summer off often means that fall is spent refreshing students on the previous spring’s lessons.

Source: Agrarian roots? Think again. Debunking the myth of summer vacation’s origins by Saskia de Melker and Sam Weber, PBS Newshour

On June 13th, 2017 we learned about

The debates and designs that resulted in the humble rubber reflex hammer

Today, while waiting in the doctor’s office for a checkup, my second grader proudly announced that she recognized the reflex hammer sitting on the counter, and that she’d figured out how to replicate its function with both her hand and lunchbox. When the doctor actually tested my daughter’s patellar ligament, there was a little disappointment that the iconic rubber hammer wasn’t used, as the doctor struck her knee with the rubber edge of her stethoscope instead. The stethoscope was effective at triggering the reflex, maybe even better than a well aimed lunchbox, so how did these hammers end up in doctors’ toolkits in the first place?

Medical grade rubber hammers were originally designed to look for fluid built up in people’s chest cavities. After seeing innkeepers thump the side of wine casks to hear how full they were, Dr. Leopold Auenbrugger suggested hitting chests with a percussion hammer to see how hollow they sounded. The idea caught on, but the design was criticized and reworked from all corners. Potential replacements looked like everything from a battle axe to a magic wand. Rubber wasn’t locked down as a material either, as doctors considered whacking their patients with ebony, whale bone, brass, lead and velvety yarn.

Knocking knees for nerves

It wasn’t until 1875 that Drs. Heinrich Erb and Carl Friedrich Otto Westphal noticed what’s been fascinating my daughter— tapping a tendon or ligament can cause the associated muscles to automatically flex and relax. The patella ligament under your knee, for instance, sends a signal through your spine to your alpha motor neuron, which then activates your quadriceps in your thigh. This response is normally used by the body to automatically maintain posture and balance without worrying about it, but for doctors it’s a handy way to diagnose an array of possible maladies. When a knee is jerked more or less than expected, it can help reveal where in the body other symptoms might be stemming from.

The iconic triangular, rubber hammer you’re likely to see at the doctor’s office was developed by Dr. John Madison Taylor in 1888. The design hasn’t changed a lot since then, but it’s not the final iteration of reflex hammers at doctors’ disposal. If the nervous response of other parts of the body are to be tested, a variety of more specialized hammers are available, such as the Krauss hammer that was designed by Dr. William Christopher Krauss. Some have large round heads for knees, small balls for biceps, and thinner structures for stimulating the skin. Of course, if all else fails, a good thump from a thumb might still do the trick as well.

Source: Digital Schmigital: After 130 Years, Reflex Hammer Still Going Strong by Bret Stetka, KQED Future of You

On May 24th, 2017 we learned about

Air pressure’s power to halt horses and carry cardboard, without pulverizing people

At first, my kids referred to what they were seeing as a “trick,” like it was part of a magic show. It was actually a well-known, kitchen-science demonstration about air pressure, but it was new and wondrous to them in a way that elicited furrowed brows and excited disbelief. I was simply holding a cup full of water upside-down, with a piece of cardboard “floating” or “sticking” underneath it. My daughter was surprised at how much the cup of water weighed, because, somehow, neither it nor the cardboard was falling all over the kitchen. “It’s like a suction cup,” she finally ventured, although it would be a bit longer before she could explain why that idea made sense.

“Wait, would this work on the Moon? With no air?”

Even though my demonstration may not seem like magic anymore, it’s good to keep in mind that for huge swaths of recorded history, most people wouldn’t have been able to really explain why my cardboard wasn’t falling away from the inverted cup. The idea that atmospheric air pressure was even “a thing” wasn’t easily tested until it could be experimentally removed by comparing normal conditions to a vacuum. Since Aristotle, people accepted the idea that “nature abhors a vacuum” to mean that vacuums just couldn’t really exist. So when German scientist Otto von Guericke visited Holy Roman Emperor Ferdinand III in 1654 for a demonstration of his new invention, nobody in the audience had any way to predict what they were about to see.

Von Guericke arrived with a 20-inch, hollow, bisected sphere and his new vacuum pump. The two halves of the sphere were placed so they touched, but their point of contact was smooth, with just a bit of grease between them. If the intersection was an equator, the “poles” of the sphere had a valve to pump out air, plus hooks that would be used later. The pump was hooked up to pump all the air out of the sphere, at which point teams of horses were hooked up on either side to try and pull the two halves apart. They couldn’t do it.

“So, there was nothing inside, but…”

Not only had von Guericke demonstrated making a vacuum inside his copper sphere, he also showcased the power of the Earth’s atmosphere. The air on the outside of the sphere was pushing the two pieces together so hard it outmatched the strength of the pulling horses. If it had been supported vertically, the bottom half of the sphere would have stayed in place even with over 4,000 pounds hung underneath it- around the weight of an adult rhinoceros. The demonstration was understandably a sensation, and the sphere was even named a Magdeburg sphere, after von Guericke’s home town. And of course, it’s basically the same concept that was holding my cardboard against my cup.

“Carrying a car?”

All that said, it was still hard for my kids to accept that the invisible air that we basically ignore all day could somehow exert so much force. We don’t see it happening, and we don’t even feel it, which seems weird, considering it’s like we’re supporting a Honda Civic all day. We don’t feel the rhino-toting power of the air all the time because unlike the Magdeburg sphere, we normally have air molecules pushing us from all directions, and they balance each other out to a degree, unless it’s windy of course.

Secondly, organisms on Earth have had millions of years to adapt to living with the air pressure here. The 2,204 pounds of pressure you can ignore coming down on your head is balanced and accommodated by the internal pressure of the various fluids that make up your body. Your blood, muscles and lungs are all full of substances pushing outwards, and they’re tuned to expect external pressure from the air pushing back. Without the right amount of pressure pushing on our bodies, things get ugly pretty fast.

At this point, my second grader seemed like the pieces were fitting together. We talked about popping ears on airplanes, the feeling of water pressure under a pool, and watching bags of chips puff up at high altitudes where there’s less air pressure. Hopefully she stays content with the cardboard demonstration, although if not, at least further tests won’t require access to a team of horses.

Source: Storm in a Teacup: The Physics of Everyday Life by Helen Czerski, Transworld Publishers Limited, 2016, p.15

On May 23rd, 2017 we learned about

Making sense of gravity, mass and weight with Galileo and my second grader

From the moment we realize we have control of our own fingers, we start learning physics. What can we squeeze? What food pours, what food falls, and what food do our parents keep putting back on our plate? At some point, our brains establish a baseline set of expectations about how the world works so that we don’t need to test it each and every time. Those so-called bits of muscle memory that enable us to catch something without thinking, or being able to estimate where a thrown ball will land, are all thanks to the many observations we’ve made about how things move here on Earth. Of course, as Galileo famously demonstrated in the 16th century, those casual observations don’t always help build the clearest picture of what really happens, even for something as mundane as two balls falling to the ground. That said, it does all make sense when you put the pieces together, as my second-grade daughter found out.

Falling feathers

We started talking about the idea of dropping a feather and a ball, which apparently added too many variables to the thought experiment. When asked to predict which would hit the ground first, my daughter was still, muttering things like “oh, but then there’s…” and “but that…” and “that should….” As amusing as it was to watch her invent new ways to furrow her brow in contemplation, we tried moving out theoretical feather and ball to the moon, cutting the Earth’s air out of the equation. This seemed to nudge her in the right direction, and she knew that the air was going to affect the feather, but putting all the pieces together into a coherent sentence was still tough, especially as a kid who would often avoids answering rather than risk being wrong.

There is a history of dropping a feather on the Moon, but that wasn’t something Galileo was even considering. He was looking to test the idea that heavy things fall faster, which was just sort of the assumed truth in Western thought since Aristotle. A feather on Earth faces a lot of resistance from air pressure, which is what was tripping up my daughter. So we reframed the discussion to more closely match the experiment Galileo conducted at the Leaning Tower of Pisa (or rather, the Nieuwe Kerk in Delft). If two balls of the same volume, but different weights, are dropped, which hits the ground first?

Testing gravity, instead of guessing

This trips people up, because many people instinctively assume that a heavier object will fall faster. At this point, my daughter ran to the toy bin and did the test herself. The balls landed together with a single, synchronized “thunk.” Her eyes popped, but she wanted another test, and with better documentation. She grabbed our old digital camera and had me take a video of her dropping the balls, then played it back in slow motion (which I didn’t even know that camera could do.) We know Galileo was somewhat surprised when he saw this result, but we can only guess if he looked quite as elated in his moment of discovery as my second grader was.

The gears in her head were still kind of grinding on how this happened though, which is fine, as plenty of adults struggle with this too. Part of the confusion is that our expectations about heavy objects falling quickly isn’t exactly wrong. Weight is the effect of gravity on mass, and objects with more mass do have more weight, meaning more attraction to the Earth in this case. The part that trips us all up is that that mass also build inertia, and so the heavier ball actually needs more force from gravity to start moving in the first place. To put it another way, when you let go of the ball, the heavier ball resists gravity’s pull more than the lighter one. Galileo apparently added an unintentional twist to his experiment, where his hand’s grip added a small delay in the release of the heavier ball, but in the end gravity gravity still got both balls to the ground at the same time, and helped get our modern understanding of motion underway.

Source: Galileo's Experiment by John H. H. Lienhard, Engines of Our Ingenuity

On May 21st, 2017 we learned about

When sumptuary laws limited the wearing of silk, lace and purple in people’s wardrobes

Today, wearing flashy outfits may garner rolled eyes and snide comments about needing a visit from the “fashion police,” but nobody will really make you give up your new silk pantaloons or rhinestone encrusted jacket. Even a forgery of a top designer won’t be a risk to carry, even if it wasn’t legally produced. We should appreciate this luxury, as ostentatious, or simply ambitious, fashion choices were once illegal. Dating back to the ancient Romans, sumptuary laws aimed to control items people could buy, largely depending on who those people were.

Identity vs. income

Sumptuary laws varied a lot over the years, and supposedly benefited society by helping curb irresponsible spending by individuals as well as normalize the supply of rarer goods on the market. For instance, a poor peasant may have been banned from buying a horse when they could barely afford to feed themselves first. By the Elizabethan era, this form of paternalistic sumptuary law probably wasn’t enforced very often, partially for practicality’s sake.

Many more details exist around laws that were intended to maintain the stratification of economic classes, often surrounding one’s dress. For example, British sumptuary laws of the 14th century spelled out exactly what job titles and income levels were allowed to wear veils, velvet, satin, sable fur, gold and purple garments, etc. There was a great concern that people might dress “above their station,” which could destabilize power structures— if a merchant wore nicer clothes than a lord, it might make the lord seem less important. If the wife of a knight wore ermine, how could anyone tell her apart from actual nobility? This tension may seem silly, but in some cases reshaped societies— merchants in the Edo period of Japan amassed significant wealth, and with it influence in society, even though they were technically ranked below samurai and nobility in the social hierarchy.

The new standard of scholars

Some of these rules are indirectly observed today, reversing their original intent. While people graduating from colleges don black robes and colored hoods to mark their accomplishments, those robes were originally just the required garb of poor students. They started as a point of practicality and warmth, were then enforced as law to identify students, later continued at specific universities as a sort of student uniform, and are now worn only to mark a student’s ascension to higher learning. The extra stripes for PhDs on their arms, fancy tassels and other detailing would probably make the authors of Medieval sumptuary laws’ heads spin, but so would the fact that the average person can now wear any nearly any clothing they can get their hands on without fear of legal repercussions.

Source: Sumptuary Laws of the Middle Ages, Lords and Ladies.org