The Explainer General
Where am I? This was a cruel question for sailors before John Harrison.
In 1707 a fleet of British warships mistook their location and sailed onto the rocky Scilly Islands. Two thousand men drowned. The Royal Navy offered a prize of £20,000 (3 to 4 million dollars in today’s money) for anyone who could provide a way for ships to find their position.
North and south latitude wasn’t the problem. Tables gave the positions of the sun, moon and stars above or below the equator. Navigators could use a sextant (it measures angles between the ocean horizon and a celestial body) to find a ship’s position north or south. But the only way of knowing your position on the spinning earth, east or west, is to know what time it is, within seconds, at the Royal Observatory at Greenwich, England—0° longitude.
Sailors needed a seagoing clock!
Clocks in the 1700’s were slow or fast by several minutes a week. Not good enough. And they measured seconds with a pendulum, which wouldn’t work on a rocking, rolling ship.
John Harrison was a fine carpenter who became fascinated by accurate timekeeping. He built big clocks for houses, barns and churches. Bit by bit he made them more accurate. He set out to win the longitude prize.
He invented ways for a clock to compensate for temperature, so they wouldn’t run slower when it got warmer. He invented a nearly frictionless escapement (the mechanism that “counts” the tick-tocks with the clock’s hands). He overcame the pendulum problem with pivoted “dumbells” that rocked back and forth with springs.
Harrison worked for five years to construct the large and beautiful Sea Clock #1. In 1736 Harrison and his clock took a trip on HMS Centurion to Lisbon, Portugal, and back. Harrison was terribly seasick. His clock was not. It was a great success.
But the Royal Navy wouldn’t award the prize. It dithered for the next 37 years. Harrison worked on, making his sea clocks smaller and more accurate. In 1761 he sent his son William on a trial run with Sea Watch #1 to Jamaica and back. The smaller clock worked beautifully. The Navy kept dithering.
Not until Harrison was 80 years old was part of the prize awarded to him. He died three years later but he knew that he had changed the world, solving one of our most important, most perplexing problems: where are we?
An important part of Jan Adkins' considerable output is books of non-fiction for young people, his special audience. He also writes humor and feature articles for several magazines. He has illustrated most of his books and contributes illustrations to dozens of mainstream magazines, especially on marine and technical subjects. Have a look at his Wooden Ship: The Building of a Wooden Sailing Vessel in 1870, a chronicle of a fictional whale ship describing and illustrating the details of her building from design to launching.
Jan Adkins is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.
MLA 8 Citation
Adkins, Jan. "Tick Tock: A Carpenter Solves an Ocean Riddle." Nonfiction Minute,
iNK Think Tank, 19 Mar. 2018, www.nonfictionminute.org/
David M. Schwartz
The amazing,engaging, math exponent
Pi Day takes place on March 14th this year, as it has every year since 1988 when this mathematical holiday was invented. Pi Day? Does that sound crazy? Sure it does. It’s irrational. Pi is the world’s most famous “irrational” number. Therefore, Pi Day is the world’s most irrational holiday!
Take a circle, any circle, and divide the circumference by the diameter. The quotient is the number called pi, represented by the Greek letter π. It is a little more than three. How much more? That is a question that people have been working on for centuries.
Pi is an incredibly useful number in mathematics, physics and engineering. It helps us understand things from the shape of an apple to the energy of stars. It helps us design things, from buildings to spaceships.
Pi is an irrational number. That means when you write it as a decimal, its digits do not just end (like 3.5) and they do not repeat in a pattern (like 0.3333…, where the 3s go on forever).
Here is a slice of pi: 3.141592653… The “dot-dot-dot” means the digits keep on going. How far? Is there a pattern?
With supercomputers, mathematicians have probed the mysteries of pi to over a trillion digits. The digits keep going. Infinitely. No pattern has ever been found. (Written in an ordinary font, a trillion digits of pi would go around the world 50 times.)
But the endless, patternless nature of pi enchants many minds and some people delight in memorizing the digits. A 69 year-old man named Akira Haraguchi recited 100,000 digits from memory in Tokyo in 2006. He shattered the previous record of Chao Lu from China, who had memorized merely 67,890 digits of pi after studying for four years.
Can you see a date in the first three digits: 3.14? It’s March 14th — Pi Day! This holiday is celebrated worldwide by students, teachers and math enthusiasts who enjoy pi-themed activities, clothing, jokes and food (namely pie).
This is an ordinary year as far as Pi Day is concerned, but in 2015, Pi Day was really special. After 3.14, the next two digits of pi are 15. So March 14, 2015, was not just any old Pi Day. It was the “Pi Day of the Century.” You’ll have to wait until March 14, 2115, for another Pi Day so sweet!
Happy Pi Day, everybody!
David Schwartz probes many mathematical mysteries in his books and school presentations given all over the world. He wrote this Nonfiction Minute while celebrating Pi Day at Tashkent International School in Uzbekistan. He is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.
MLA 8 Citation
Schwartz, David M. "Happy Pi Day." Nonfiction Minute, iNK Think Tank, 14 Mar.
David M. Schwartz
The amazing, engaging, math exponent
Imagine Earth as a button. I don’t mean you’re going to sew it onto your shirt. But imagine the planet Earth shrunk to the size of a button. (Of course Earth is not flat like a button but we’re giving our shrunken Earth the same diameter as a shirt button.)
Go ahead and draw a circle around a shirt button. Call it “Earth.” Suppose you wanted to draw Jupiter, the largest planet, at the same scale as this micro-Earth. That means you’re going to shrink it to the same fraction of its original size as our button-Earth. What size would little Jupiter be?
One way to find out would be to calculate how many times bigger the real Jupiter is than the real Earth. Earth’s diameter is about 8,000 miles (13,000 kilometers). Jupiter’s is about 88,000 miles (143,000 km). Divide the size of Jupiter by the size of Earth to see that Jupiter is about 11 times bigger.
So, since Jupiter’s diameter is 11 times that of Earth’s, put 11 buttons in a line to show the diameter of Jupiter. Then draw the circle that represents Jupiter. If you don’t have 11 buttons, just look at the picture. Did you think the Earth was a big place? Look at it compared with Jupiter!
But what about the sun? The sun’s diameter is about 865,000 miles (1,400,000 km). That means it’s almost 10 times bigger than Jupiter. Can you find a way to draw a circle 10 times the size of our Jupiter? We’ve drawn part of it for you, on the same scale as our button-sized Earth. On the picture, it’s labeled “our arc.” (An arc is part of a circle.) Looking at the arc, you can imagine the rest of the circle and compare the sun to Jupiter and Earth. A minute ago, you thought Jupiter was big. Now it looks shrimpy compared to the sun!
But is the sun really gigantic? Do some research to find out the size of a red giant star like the strangely named Betelguese (pronounced “beetle-juice.”) Figure out what it looks like compared to our sun, which is a medium-sized star. You may be amazed at the difference. And you thought the sun was big!
Is anything truly big? Is anything truly small? Or does that depend on what it’s being compared to?
Both images are by Marissa Moss, the illustrator of David M Schwartz's book, G is for Googol.
G is for Googol: A Math Alphabet Book is a wonder-filled romp through the world of mathematics.
For more information, click here.
David Schwartz is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.
Schwartz, David M. "If the Earth Were a Button." Nonfiction Minute, iNK Think
Tank, 16 Jan. 2018, www.nonfictionminute.org/the-nonfiction-minute/
Are you tougher than a tardigrade? I don’t think so.
These typically water-dwelling animals may be microscopic in size (barely half of a millimeter when fully grown!), but boy are they fierce. Sometimes called “water bears,” they’re anything but cuddly. Each of their eight legs is decked out with wicked claws. Some tardigrades have full body armor. Most have specialized "sucker" mouths to pierce the cells of plants and animals and suck out their nutrients, while others prefer to consume their tiny prey whole… and that prey might even be another tardigrade!
Aside from ending up as someone else’s dinner, though, tardigrades are practically indestructible. They can survive in just about any conditions and take on just about anything life has in store for them. Starvation? No worries there: Tardigrades can go without food for at least 10 years. What about water, you say? No problem. They’ll just suspend their life activities and wait until the drought is over. They can survive at pressures more than six times that of the deepest ocean trenches. And, you’d die from radiation poisoning long before a tardigrade would even notice. Scientists have even tried shooting them into outer space… and the tardigrades survived.
Because of their ability to live practically anywhere, these little guys are practically everywhere. Tardigrades can be found on top of Mount Everest and in boiling hot springs, in desert dunes and rainforest canopies, in freshwater lakes and salty oceans, on your roof, outside your front door… maybe even in your bed or on your dinner plate! There are billions and billions of tardigrades… and they’re always making more!
Fortunately, there’s no need to worry—tardigrades are completely harmless to humans. In fact, tardigrades may actually end up being our best friends someday. Because they can do so many things that other Earthly animals can’t, scientists are studying tardigrades to try to find solutions to all kinds of problems. Want to dry something out to preserve it, then rehydrate it later? Study how tardigrades do it. Wish we could safely reanimate something that has been frozen? Learn from the tardigrades. Need to protect cells from being damaged by radiation? Figure out why tardigrade cells can withstand it.
Who knows? Someday the tough tardigrades might teach us all kinds of handy tricks!
Tardigrades are short and plump, with four pairs of legs, each with four to eight claws also known as "disks." Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012)/Wikimedia Commons
An adult Milnesium tardigrade, an example of more than 1,000 species of the tiny animal. Bob Goldstein and Vicky Madden, UNC Chapel Hill/Wikimedia Common
This video shows a tardigrade in real time at 100X magnification. Dmitry Brant via Wikimedia Commons
Laurie Ann Thompson and coauthor Ammi-Joan Paquette begin a fascinating new series with Two Truths and a Lie, a book that presents some of the most crazy-but-true stories about the living world. Some of the stories are too crazy to be true—and readers are asked to separate facts from fakes! "A brief but savvy guide to responsible research methods adds further luster to this crowd pleaser.” —ALA Booklist (starred review)
MLA 8 Citation
Thompson, Laurie Ann. "Tardigrades Make the Grade." Nonfiction Minute, iNK Think
Tank, 21 Mar. 2018, www.nonfictionminute.org/the-nonfiction-minute/
Dorothy Hinshaw Patent
Nature’s Animal Ambassador
People are confused. They hear the terms “global warming” and “climate change” tossed about without much explanation. We all talk about the weather, but what does that word actually mean, and how does it relate to these other terms?
NASA defines global warming: “Global warming is the increase in Earth’s average surface temperature due to rising levels of greenhouse gases.” So global warming is a measurable statistic. Record the temperature at many sites on Earth for a given year, add them up, and divide to get an average. Rising levels of greenhouse gases are also well measured. The famous “Keeling curve” of atmospheric CO2 begun in Hawaii in 1957 is the best example.
Climate change is more complicated. Climate change is a long-term change in the Earth’s climate and includes measures of the atmosphere, oceans, land, cryosphere (snow and ice), wind, precipitation, deforestation, wildfire, and more, as well as temperature. So, climate change is a more inclusive measure of many factors changing the Earth system, which is very different from a single statistic like the rise in temperature from global warming.
Then there’s the weather. What, exactly is the weather? That term refers to what’s going on in the atmosphere at a particular time and place. It includes the air temperature, wind speed, humidity, and precipitation. Weather happens day to day, while global warming is shown by recording day-to-day temperatures over a long period of time. Climate change is a long-term process that can result in drastic changes in conditions on our planet.
To sum up: Weather refers to what’s happening in the atmosphere at a given time and place over the course of days to months.
Global warming refers to an upward trend in the average temperature over a period of years to decades.
Climate change is a long-term process that can be influenced by changes in the average temperature but includes many other factors.
To watch a brief but amazing video of the affect of global warming and climate change over the next 20 years, click here.
Dorothy's recent book The Call of the Osprey, has been chosen as a Best Science Trade Book for Students by the National Science Teachers Association. It covers research being done in Western Montana by scientists at the University of Montana. Starting in the late 1800's, Butte, MT, at the headwaters of the Clark Fork River, was the largest copper mine in the U.S. The major result of the mining was two-fold—the electrification of America and the largest Superfund cleanup site in the U.S. Call of the Osprey deals not only with current research but also with the history of Butte and the lives of the scientists involved in the research. Click here to find out more.
Dorothy Hinshaw Patent is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.
MLA 8 Citation
Patent, Dorothy Hinshaw. "Defining Weather, Global Warming, and Climate Change."
Nonfiction Minute, iNK Think Tank, 16 Apr. 2018,
For Vicki Cobb's BLOG (nonfiction book reviews, info on education, more), click here: Vicki's Blog
The NCSS-CBC Notable Social Studies Committee is pleased to inform you
that 30 People Who Changed the World has been selected for Notable Social Studies Trade Books for Young People 2018, a cooperative project of the National Council for the Social Studies (NCSS) & the Children’s Book Council