July 25 – Last Leg To Stand On

Today’s factismal: The Solar Impulse II is on its last leg of an around-the-world flight.

All too often we forget that the future is happening now but it started long ago. For one example of that, I point you to the Solar Impulse II. This amazing aircraft is designed to take off, fly, and land using nothing but the solar power it harvests with the solar cells on its wings. Though it will never be able to carry anything other than two pilots and a very minimal cargo, the airplane will demonstrate that we have only begun to tap into what can be accomplished.

And what can be accomplished? Lots! Right now, the solar powered airplane is on the last leg of its around-the-world flight that started on March 9, 2015. It has already set several records, including longest flight by a solar-powered airplane (4,819 nmi from Japan to Hawai’i) and the longest non-stop solo flight without refueling (Japan to Hawai’i again). More importantly, it has shown that we can do a lot more with solar power and other alternative energy sources. When it touches down in Abu Dhabi next month, this plane will become the first solar powered plane to circumnavigate the globe.

The Solar Impulse in flight (Image courtesy Solar Impulse)

The HB-SIA in flight
(Image courtesy Solar Impulse)

But where and when did this airplane start? (Other than last March in Abu Dhabi.) Perhaps we should point our fingers at Elmer Johnson, who was awarded US patent 3,089,670 for a solar-powered aircraft on May 14, 1963. But Elmer points his finger at others (including one gentleman who wanted to build a solar-powered flying saucer). And, if we follow the line of patents far enough back, we’ll find ourselves looking at a certain patent clerk by the name of Albert Einstein who first deduced how solar power cells work back in 1915.

If you’d like to spend some time looking forward, then why not check out the Solar Impulse?

October 18 – Winner By A Landslide

One of the amazing things about science is how often things at one scale apply at another as well. For example, you can measure the way that a cup of lye reacts with a cup of water and know how much heat will be produced if you use a ton of lye and a ton of water instead. Or you can simulate an earthquake using a piece of spaghetti and that will teach you something about how the San Andreas behaves. Or, as Peter and Mary are about to discover, you can use a pile of rice to discover why the Earth is round.


The images on the television were both frightening and fascinating. There had been a heavy rainfall in California and the runoff was rapidly eroding the base of a cliff, causing parts of the cliff to collapse in large chunks that splashed mud and mayhem when they fell. That would have been fascinating enough but on top of the cliff were several multi-million dollar mansions that were following the formerly stable cliff on its downward plunge.

“Wow!” said Peter as he watched a particularly large chunk of a swimming pool fall twenty stories into the surf below. “That was amazing!”

“Yes,” agreed Mary. “I’m glad that they got all of the people out. But what about their stuff?”

“I guess they’ve got insurance,” Peter replied. “But why did they build on the cliff?”

“Probably for the view. But what I want to know is why isn’t the cliff still still standing?” Mary puzzled. “It was doing OK before the rain, so why fall now?”

“I dunno. Who could we ask?” Peter wondered.

“Well, Mr. Medes is on vacation this week, so we can’t ask him,” Mary said. “And your mom is an astronomer, so she wouldn’t know. That just leave my dad. But he’s an engineer. He probably won’t know either.”

“Well, there’s only one way to find out,” Peter said. “Let’s go ask him!”

With that the two young scientists left the den where they had been watching television and sought out Mary’s father. Since it was Saturday, the first place they checked was the kitchen; in addition to being a popular engineering professor at the local university, he was also an amateur gourmet chef who liked to make special meals on weekends. Sure enough, he was in front of the stove, cooking raw rice in oil and fragrant spices.

“Oh, boy!” Mary exclaimed. “Costless Rican Rice again?”

“You betcha!” her father replied. “I wanted to use up the last of that roast chicken and we had enough vegetables to make this interesting. Peter, would you like to stay for dinner?”

“I’ll ask my mom,” Peter said as his belly rumbled in response to the smell of the cooking. Mary’s father laughed at the sound.

“It sounds as if your stomach has already decided the answer will be ‘yes'”, he said as he stirred the rice. “So what may I do to help you two? Or are you just drawn to the sight of a master turning leftovers into a meal fit for a king?”

“We had a question about cliffs,” Mary said. “Why do they fall down?”

“That is an excellent question!” Her father boomed in response. “And I’ll tell you the answer just as soon as I toss these odds and ends into the rice.”

With that, Mary’s father scrapped chunks of cooked chicken and vegetables that were left over from the previous week’s meals into the rice. Pouring in a carefully measured amount of water, he gave the mass a final stir and put a lid on top. He then turned the heat down and turned to his daughter and her friend.

“So you want to know why cliffs fall down,” he said. “Why do you ask?”

“Well, we saw these cliffs in California that were falling apart and dragging the houses that were on top of them into the mud,” Mary said. “But the cliffs were only about two hundred feet tall. We’ve got skyscrapers that are ten times as tall. So why do the skyscrapers stand up and the cliffs fall down?”

“It turns out that you have come to exactly the right person to answer that question,” her father replied. “Though Peter’s mother might have done just as well; this applies to her field as well.”

“It does?” Peter asked. “How?”

“You’ll see!” Mary’s father replied. “To start with, we’ll need a couple of plates, some toothpicks, and some uncooked rice.”

Mary quickly went to the pantry and grabbed the things that her father had listed off. Her father took the plates from her and placed on in front of each of the scientists. He then gave them each a toothpick and poured a cupful of rice onto each plate.

“In front of each of you is a pile of rice,” he said. “What I want you to do is to make the tallest cliff of rice that you can by scraping away the rice at the bottom of the pile with the toothpick. When you are done, what do you think the cliff will look like?”

“It will be just like a real cliff,” Peter confidently said. “It will go straight up.”

“I’m no so sure,” Mary countered. “I think it will be a lot slope-ier. It will probably lean over more.”

“Well, there’s only one way to find out,” her father said. “Start scraping!”

What do you think will happen? Try the experiment yourself!

The two started scraping at the base of their rice piles. But as soon as they would start to build up a small cliff, the bottom would slide out and a small cascade of rice would flow down, turning the vertical wall into a horizontal slope. After a few minutes of diligent scraping, Peter tossed down his toothpick in disgust.

“I give up!” he declared. “The rice won’t make a cliff! It is even worse than what we saw on TV!”

“Peter’s right,” Mary agreed. “You can’t make a tall cliff out of rice.”

“You are both right,” her father said. “You can’t make a tall cliff out of rice and you can’t make a skyscraper out of sand. And in both cases, the reason is the same.”

“It is?” Mary asked.

“Yes,” her father replied. “What is happening is that every stack of stuff is a balance of two things. There is gravity, which is pushing down on all the parts of it and there is cohesiveness which is trying to keep everything together. When gravity pushed on the center of a pile of rice or a cliff or a skyscraper, the force is straight down. That creates pressure on the grains of rice which gets bigger as you go deeper into the pile. The rice on top feels very little pressure while the rice at the bottom feels a lot. If the pressure on a grain of rice is about the same as the pressure on the grains around it, everything is stable and nothing moves. But if the pressure is lower on one side, then things naturally try to move in that direction. And when the difference in pressure is greater than the cohesiveness, then -”

“You get a landslide!” Mary exclaimed.

“That’s right!” her father agreed. “If you watched carefully during your experiment, then you probably saw that the rice-slides only happened on the side where you were scraping. That was because that was the only side where the pressure was changing.”

“Oh!” Peter said with a look of sudden understanding. “And that’s why the cliffs were falling. When the water eroded enough of the base, the pressure from the dirt piled up in the cliff was more than the strength of the stuff holding the cliff together and – pow! – we got a landslide!”

“That’s right. And that should also tell you why you can’t build a twenty story cliff of rice or a two hundred story cliff of sand,” Mary’s father said.

“Because rice isn’t as strong as sand and that’s not as strong as the steel in a skyscraper!” Mary said. “But why could Peter’s mother have told us this, too?”

“Because she works with planets,” her father replied. “And the one part of the definition of a planet that everyone agrees on is that they are round thanks to their own gravity.”

“I don’t get it,” Peter said.

“Imagine that you are building a cliff of sand,” Mary’s father said. “What happens if it gets too tall?”

“Some of it collapses,” Peter said.

“OK, now imagine that you’ve got a pile of sand as big as a planet,” Mary’s father said. “What happens to that cliff?”

“It will collapse,” Mary said.

“And if the cliffs that creates are too tall?”

“Then they will collapse too,” Peter said.

“And what happens if you keep doing that all around the planet-sized sand pile?” Mary father asked.

“I get it!” Mary said. “No matter where you look, the sand piles can only be so tall. And that means that everywhere you look, everything is about the same distance from the center of the planet. And that makes it -”

“Round!” Peter and Mary chorused together.

“That’s right,” Mary’s father said. “And now, if you two will clean up your budding planets and if Peter will call his mother, we can eat dinner.”

With that reminder, Peter’s stomach once more rumbled threateningly and all three laughed as they set the table for dinner.


September 15 – How Clever!

Today’s factismal: The word engineer comes from the Latin word ingenium which means “cleverness”.

If you want to start an argument at a science conference, as the folks there who the first scientist was. They’ll argue all day and night, complete with glossy photos covered with circles and arrows and with references on the back of each one, trying to decide if Pythagoras was a scientist or just a guy with a bean fetish. But if you ask a group of engineers who the first engineer was, you won’t get an argument. That’s because nobody knows; ever since there have been people, there have been engineers that built things to make the people more comfortable.

The outside of the coliseum at Pompeii (My camera)

The outside of the coliseum at Pompeii; a deceptively simple feat of engineering
(My camera)

The inside of the coliseum at Rome; witht eh wooden seats gone, you can see the involved engineering (My camera)

The inside of the coliseum at Rome; with the wooden seats gone, you can see the involved engineering
(My camera)

Engineers built the hanging gardens of Babylon. Engineers built the pyramids of Egypt. And engineers built the marvel that was Rome, from her majestic aqueducts to her ubiquitous roads to her incredible coliseums. And, in return for all that the engineers gave Rome, the Romans gave engineers a name: ingenium or “clever folks”. And those clever folks have kept giving us marvel after marvel.

Even when the engineering doesn't quite work, it is still miraculous (My camera)

Even when the engineering doesn’t quite work, it is still miraculous
(My camera)

Today is International Engineer Day. So be sure to look at the freeway you drive on or the house you live in or the plane flying overhead and give thanks that those clever folks are still at it. Of course, if you’d like to help create the next generation of clever folks, then there’s a citizen science program for that: Free Geek. These engineers are determined to help make certain that every aspiring engineer has the tools that she or he needs by refurbishing used computer equipment and donating it to low-income families. They started in Portland, Oregon, but have since spread to several other states. To donate or take part, head over to:

July 13 – Under Stress

Today’s factismal: Eugène Freyssinet, father of the modern highway, was born 135 years ago today.

If you’ve ever looked at a highway overpass being built, then you’ve probably wondered “what are those wires in the concrete and why are they there?” The wires sticking out of the concrete are called tension cables and are there to make the concrete stronger by squeezing it. And the engineer who first figured out why they should be there was named Eugène Freyssinet.

Without prestressed concrete, this is what our highways would look like (Image courtesy Pont du Gard)

Without prestressed concrete, this is what our highways would look like
(Image courtesy Pont du Gard)

Large bridges are nothing new. The Romans had aqueducts (large canals to carry water) that stood 160 ft high and stretched more than 1,000 ft. But their bridges were built from brick and mortar and literally required tons of material in order to keep from breaking apart from the sheer weight of the top sections. If you look at the Brooklyn Bridge, you can see how little had changed in the world of construction between the time of the Romans and the 1800s.

Tension wires sticking out of a prestressed concrete arch; without them, the arch would fall apart. (My camera)

Tension wires sticking out of a prestressed concrete arch; without them, the arch would fall apart.
(My camera)

The reason that large bridges (and buildings and monuments, for that matter) needed so much stone was because most things are very weak when they are being pulled apart (are in tension) but are much stronger when they are being squeezed together (in compression). To understand this, consider the difference between a small pile of sand that you can easily deform with a finger and the same pile of sand stuffed into a rubber balloon where it takes a lot more strength to change its shape.

Though a lot of people knew about this effect, it took Eugène Freyssinet to develop a way of applying it to the real world. He discovered that by stretching wires out and casting the concrete around them, he could prestress the concrete and make it much stronger. As a result, he was able to build bridges that were longer and stronger than anything that was ever done before.

The TWA Flight Center at JFK (Image courtesy Ton Stam)

The TWA Flight Center at JFK
(Image courtesy Ton Stam)

And his discovery wasn’t limited to bridges. If you’ve ever seen the TWA Flight Center at JFK airport, or the LAX airport, or the Sydney Opera House, then you have seen prestressed concrete at work.

If you’d like to explore more, or search through thousands of other science topics, then why not look over the National Science Data Library? It is a free website with education plans for teachers and fun facts for everyone else!

July 1 – Without A Paddle

Today’s factismal: The Great Mississippi Flood of 1927 covered an area larger than West Virginia

The mighty Mississippi is famous in song and story, and for good reason. At 2,340 miles long, it is the second longest river in the USA. With a drainage area of 1,150,000 sq mi, it covers nearly 40% of the USA. And with an average discharge of 593,000 cu ft/s, it moves enough water to completely cover Louisiana to a depth of ten feet in just one year!

A ferry crosses the Mississippi River in New Orleans (My camera)

A ferry crosses the Mississippi River in New Orleans
(My camera)

Of course, that drainage is all well and good when it works. But sometimes it fails and the water comes in faster than it can drain away. When that happens, we get a flood. And the worst flood in US history happened in 1927 when a series of strong rainstorms lingered through summer and into fall and winter. Every day, the Mississippi’s level rose more and people got more worried. On Christmas Day, the river finally over-topped its banks and the levees that had been put into place to prevent flooding. That quickly led to catastrophic flooding with the river breaking through the levee in more than 45 places. Before it was over, more than 27,000 sq mi of land would be flooded – an area the size of West Virginia!

The area covered by the Great Mississippi Flood of 1927 (Courtesy US Archives)

The area covered by the Great Mississippi Flood of 1927
(Courtesy US Archives)

The flood did more than $400 million in damage ($5.230 billion in 2013 dollars) and killed 246 people. It also changed the way that we treated the river. Up until that point, the belief had been that we could control flooding by constructing bigger and stronger levees; the Great Flood of 1927 showed that the effects were worse when those levees broke than it would have been if the levees had never been built. As a result, today the US Army Corps of Engineers and local flood agencies work to divert flood waters into temporary catchments and alternate rivers. Though this hasn’t prevented the Mississippi from flooding, it has reduced the damage done when it does flood.

Of course, the Mississippi isn’t the only river that floods. And naturally, there’s an app for that. Called FloCast (Flood Observations – Citizens As Scientists using Technology Project), the app was designed by the University of Okjlahoma to let you provide information on local stream conditions to scientists who are trying to discover where the next great flood will happen – and stop it.

June 27 – What a ride!

Today’s Factismal: The escalator was invented  in 1892 as an amusement park ride for Coney Island.

It isn’t just girls; all people just want to have fun. We like to go exotic places, and we like to eat strange foods, and, most of all, we like to ride thrilling rides. And in the late 1800s, Coney Island was the perfect place to do all three.

Coney Island had started as a typical seaside town, with fishing and shipping and not much else. But the hot New York summers meant that people in New York City wanted to go someplace cool to escape the dust and dirt of the city. So it flourished as a resort in the early part of the 1800s. Once a newfangled railroad was laid to the town, it became even more popular as people could ride an early train to the resort, lounge by the sea for a few hours and then go home to sleep in their own beds.

A relative of the great elephant built at Coney Island; this one is Lucy in Atlantic City (My camera)

A relative of the great elephant built at Coney Island; this one is Lucy in Atlantic City (My camera)

The influx of people hungry for adventure and flush with cash meant that there were plenty of locals looking for ways to provide the adventure in return for a little of the cash. In 1876, a carousel opened, delighting and dizzying passengers. In 1885, a lighthouse shaped like an elephant was built to give the day trippers a sense of whimsy in exchange for a nickle. And, in 1895, perhaps the most daring joyride of all opened: an inclined moving stairway (called an “inclined elevator”) that would take passengers up a 25 degree slope. This ride was immensely popular and soon led to the establishment of Steeplechase Park, the first of three Coney Island amusement parks.

A view of the original "inclined elevator" (Image courtesy IdeaFinder)

A view of the original “inclined elevator” (Image courtesy IdeaFinder)

The inclined elevator was the brainchild of Jesse W. Reno. A native of New York city, Reno had worked as a mining engineer before becoming an inventor. Perhaps the view he had of ores being moved up to silos by endless belts inspired his creation, or perhaps it was just a bolt from the blue. What is certain is that he was awarded patent # 25,076 on March 15, 1892 and built his first working model at the Old Iron Pier in 1895. The ride was a resounding success and soon attracted the attention of the Otis elevator company. They bought his invention, renamed it an escalator, and soon sold them to department stores across the country. Today, the descendents of Reno’s ever-ascending invention can be found in malls, stores, and airports across the globe.

But Reno isn’t the only inventor, and the search for a better ride continues today. If you’d like to help improve the modern thrill ride known as the car, then head on over to ChargeCar; they need information about your daily ride to help build a better electric car.

June 18 – Making Sparks

Today’s Factismal: The first modern battery was built in order to investigate frog’s legs.

If you’ve studied the history of science, then you know that nothing drives the discovery of new things like an argument between two scientists. Cope fought with Marsh and the result was an (almost literal) explosion of new dinosaur discoveries (including some that weren’t). Hawking fought with Presskill and the result was a deeper understanding of how black holes work (and a new encyclopedia for Presskill). Newton fought with Leibnitz and the result was a new type of math that would describe the universe and plague college freshmen forever after. And, around 1780, Galvani fought with Volta and the result was the discovery of how nerves work and how to create electricity.

As with most feuds, it started over something small but interesting. While Galvani was working with frog’s legs, trying to tease out the secret of the nerves, his assistant touched a frog’s leg with a scalpel – and it twitched! If your pork chop dinner jumped up and did the tango, you wouldn’t have been half as astonished as the two scientists were. They quickly tried an assortment of things to replicate the result and discovered that it only worked when the metal scalpel touched the frog’s leg; feathers, wooden sticks, and quill pens had no effect. Galvani declared that he had discovered “animal electricity” and sent the details out to the world.

Volta, who was a sometime colleague of Galvani’s, wasn’t convinced. He replicated the experiment and was able to make twitching frog’s legs of his own, but he didn’t think that the secret was in the animal; he thought that it was in the scalpel. If the electricity were in the animal (as Galvani supposed), then just about anything would have made it twitch. But if the electricity were being created by the metals, then only being touched by a metal thing would make it twitch. And in a series of experiments stretching over several months, that’s exactly what Volta proved: it was the two metals that made the electricity.

Look, ma! I made a battery!

Look, Ma! I made a battery!

But then Volta went one step further and made the world’s first modern wet cell battery. He kept the two metals but substituted paper soaked in salt water for the frog’s legs (the paper stacked better). By alternating layers of metal and slipping paper between the metal, Volta was able to generate a steady electric current. The modern lead-acid battery (found in most cars) was born.

If you’d like to build a “Voltaic pile” of your own, all you’ll need is five nickels, five pennies, some paper towels, a plate, and a bowl of salt water. First cut small circles out of the paper, just slightly smaller than a penny. Next, put a nickel down on the plate. Dip a paper circle into the salt water and then place it on top of the nickel. Top it with a penny, then dip another paper circle into the salt water and put it on top of the penny. Continue stacking the coins and paper until you’ve got a tower ten coins high. Your battery is now done! To see if it is working, you can try connecting it to a LED or ammeter with a pair of wires or simply touch the ends of the wires to your tongue; the bitter taste you get is caused by the flow of electricity across your tongue.

And the coolest thing about making that Voltaic pile is that it means you’ve made something on The National Day of Making. For more making ideas, go to: