### February 29 – Happy Birthday, Leaplings!

Posted on February 29, 2016

There are probably roughly one-fourth as many leaplings – people who have a February 29th birthday – as there are people with any other specific birthday (such as April 26 or October 10). That's because leaplings are born on Leap Day – February 29 – and there is only one Leap Day per every four or so years.

The reason I say “or so” is because a few “every four years” years are not leap years. The rule is complicated:
• If a year can be even divided by 4, it's a leap year.
• UNLESS it can also be evenly divided by 100, in which case it is not a leap year.
• UNLESS it can also be evenly divided by 400, in which case it is back to being a leap year!

The reason for all these complications is that leap days are added to the calendar so that the calendar keeps time with the Sun. And it takes the Earth 365 days, 5 hours, 48 minutes, and 45 seconds to circle once around the Sun...So instead of giving us a nice clean 365 days a year, or a still-pretty-clean 365.25 days in a year, we have 365.242189 days per year!

You may remember that the year 2000 was a leap year, but the years 1800 and 1900 were not.

ANYWAY...

Four years ago I wrote about Leap Day, and here we finally are again. This time, I thought I would celebrate a few people born on this rarest of days...

Vance Haynes, Jr. is an archeologist and a geologist. He revolutionized his field, which is geoarchaeology – also known as archaeological geology. He helped figure out the timeline of human migration into and through North America, and he helped maintain scientific access to important human skeletal remains.

Even though he was born on this day way back in 1928, Haynes is still active in the School of Anthropology at the University of Arizona! (He turns 88 today – hooray!)

Seymour Papert is a mathematician, a computer scientist, and an educator. He is one of the pioneers of A.I. (artificial intelligence), and best of all, he and a co-inventor created the Logo programming language.

Logo is a programming language that helps kids learn how to program. Papert created a small robot called the Logo Turtle. Kids could give it a list of movements to make – including “Pen up” and “Pen down,” and they could use the turtle to draw designs.

And not just simple designs, either! Using Logo is a great way to learn about recursion. It is recursion that makes fractals possible!

 Recursion is when you repeatedly call on a routine.In the example above, all the turtle is doing is drawingboxes. But in between each box, the turtle just turns a littlebit so that the next box is slightly offset from the last.And when you do that over and over and over again, theresult is surprisingly pretty!The example below is a different routine that is called onover and over - with a different, even more complex, result.

Like Haynes, Papert was born on this date in 1928. He was born in South Africa,
got his PhD in England, and has lived in the U.S. since 1963.

Tim Powers is a science fiction writer (like me! – but way more successful!). He was born in Buffalo, NY (near where my husband was born!) and now lives in San Bernardino County, Southern California (like my husband and me!), and he sometimes teaches in the Orange County High School of the Arts and Chapman University (my daughter's alma mater!).

Powers and a few of his pals started the steampunk literary movement (which has spilled out into fashion and design and style). Steampunk is a kind of alternative history fiction in which steam power remains the most important form of energy. Steampunk is generally inspired by Victorian times.

Powers was born on this date in 1952.

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### February 28 – National Science Day in India

Posted on February 28, 2016

One of India's most recognized and respected scientists is C.V. Raman.

I like referring to him as “C.V.” because his full name is Chandrasekhara Venkata Raman. Which is a lot to type.

On the other hand, like Charles Darwin and Albert Einstein, at least spell check know's Raman's full name and didn't allow me to accidentally type something like Chardrasekhara or Chandrasakhara or....whatever else my flying fingers blundered out.

And since 1929, Raman's full name ALSO included “Sir,” because he was knighted by Britain.

So, why am I bringing up Sir Chandrasekhara Venkata Raman today? Just because he was an Indian scientist and today is National Science Day in India?

Actually, it is because of Raman that today was chosen to celebrate and promote science in India – because today is the anniversary of his most important, Nobel-Prize-worthy discovery: the Raman effect.

So...what's the Raman effect?

Simply stated, the Raman effect is the inelastic scattering of light.

You probably know that visible light is a form of electromagnetic radiation, along with infrared, microwaves, X-rays, radio waves, and ultra-violet light. All electromagnetic radiation travels in little “packets” called photons.

I bet you have heard that, on a clear day, the sky looks blue because of scattering. But what is being scattered by what?

Air is not empty space – it's full of lots of different particles and molecules, most of which are invisible to us. When light from the Sun hits particles or molecules, some of the photons's paths are disrupted, and the various photons scatter about randomly. And blue photons have the tiniest wavelengths of all visible light, so they tend to get scattered more than green or yellow photons, and especially more than orange or red photons.

This is called Raleigh scattering, or elastic scattering. The photons that scatter shoot off on other, random paths, but they don't change their frequency and wavelength. In other words, a photon of blue light stays a photon of blue light.

In 1923, a physicist predicted that a few photons would scatter in another way. They would scatter by excitation – in other words, they would change frequency and wavelength, either gaining or losing energy. A photon of blue light might become a photon of red, or vice versa.

 In the diagram above, the incoming Sun's light is yellow,as is the Raleigh-scattered light. The two pink arrows show the Raman-scattered light.In the diagram above, the green laser shines through a crystal.Some of the light is scattered. Most of the scattered light isstill green (Raleigh - elastic), but a bit of it is now pink (Raman - inelastic).

On this date in 1928, Raman and K. S. Krishnan discovered the predicted behavior. Only about one photon in 10 million changes wavelength as it scatters, but they were able to observe it as light passed through a liquid.

(Actually, two Soviet scientists discovered this same sort of scattering as light traveled through crystals about a week before Raman and Krishnan's discovery! The reason that the “effect” is named after Raman – and the reason that Raman and Krishnan share a Nobel Prize for the discovery – is that the Indian scientists published their findings before the Russian scientists did.)

In 1928, the Raman effect seemed important to scientists, especially those in the field of spectroscopy (the study of light that has been emitted from, reflected from, or shone through a gas, liquid, or solid). But I don't know that the Raman effect had much...um...effect on the rest of us. However, these days there are a lot of utilities in many different fields. Here's a practical one: a Raman scanner is a hand held device used to detect drugs, explosives, hazardous chemicals, gases, and so forth. It is used by narcotics squads, airport security, forensic detectives, and security experts.

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### February 27 – Happy Birthday, Constantines

Posted on February 27, 2016

On this date in 272, Constantine was born. He became a Roman emperor and “the Great” was added to his name at some point...

About a millennium and a half later, on this date in 1711, Constantine Mavrocordatos was born. He later became a prince and ruler within the Ottoman Empire.

Constantine the Great rose through the Roman military based on his own abilities, but his army-officer father became a “deputy emperor” – a sort of vice-emperor, or junior emperor, which confusingly was known as a “Caesar,” second in command to the senior emperor, known as an “Augustus.” At the time there were at four men with the power of leading the enormous Roman Empire: an Augustus and a Caesar in the West and an Augustus and a Caesar in the East.

Later, his father was raised up to being the Augustus of the West, and when his father died, Constantine was acclaimed as emperor (Augustus) by his army.

The transfer of power was not super peaceful. There was a series of civil wars and the various Caesars and Augusti fought among each other. Constantine led his army to victory after victory, and by the year 324, he became the one emperor of both the Western and Eastern Roman Empires.

Here are some things Constantine is famous for:

• He built a new imperial fortress at Byzantium, in what is now Turkey, and then renamed the city after himself: Constantinople. (This city is now named Istanbul.) Constantinople became the capital of the Roman Empire for more than a thousand years (although we now call this empire the Eastern Roman Empire or the Byzantine Empire).

•  Even though Constantine rose to power largely"through the sword" - some see his poweras coming "from the cross."
He was the first Roman emperor to claim to be converted to Christianity, and he legalized the religion throughout the empire. He called the First Council of Nicaea, which is an important part of the history of Christianity—and some Christians still honor Constantine as a saint.

• Constantine separated civil and military authority. That is a split that most modern democracies and republics use. For example, the elected president and governors and mayors rule civil life, and police and civil judges enforce civil laws – but admirals and four- and five-star generals rule the military, and there are separate military police and military courts for enforcing military laws.

• Constantine not only ruled a unified Roman Empire, he also enlarged it. He attacked some of the tribes on the frontiers of the empire, including lands that had been considered a part of the Roman Empire but had been abandoned by earlier emperors – and he won pretty much every campaign. Constantine had reorganized his army into mobile field units and garrison soldiers; this reorganization probably accounts for some of Constantine's success.

• Paragon of virtue and military hero? Or monstrous tyrant who ruled harshly? Different groups have portrayed Constantine differently. Modern historians generally take a middle ground.

Constantine Mavrocordatos was a Greek noble who was born in Constantinople and who ruled as Prince of Wallachia and as Prince of Moldavia. He didn't rule for one long period of time – I guess things were not so peaceful in the Ottoman Empire, in the 1700s. Instead, his reign over Wallachia went something like this:

• 1730 (just part of the year)
• 1731 – 1733
• 1735 – 1741
• 1744 – 1748
• 1756 – 1758
• 1761 – 1763

And his rule over Moldavia was during some of his “off” times:

• 1733 – 1735
• 1741 – 1743
• 1748 – 1749
• 1769

If you're like me, you have no idea where Wallachia was; it was located in what is now Romania.

If you're like me, you will wonder if Moldavia is the same thing as modern Moldova; actually, the western half of historical Moldavia is a part of Romania, the eastern side is the Republic of Moldova, and some northern and southeastern chunks are now parts of Ukraine.

What Constantine the Great and Constantine Mavrocordatos have in common, besides for their name and birthday, is the city of Constantinople. So here is a photo essay of Byzantium / Constantinople / Istanbul:

 Istanbul is a modern city, but you canstill see some of the ancient walls and gatesin places.

 Many of the Christian churches were convertedinto Muslim mosques, although many Christianchurches and some Jewish synagogues can befound in the city.

 Modern markets combine old and new.
 And a REALLY modern hotel is largelyunder the sea!

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### February 26 – Tell a Fairy Tale Day

Posted on February 26, 2016

Once upon a time, people told stories orally, and the stories passed down from parents to children to grandchildren...and on and on. Of course, you know how it is – favorite stories tend to be retold the same way each time (most kids complain if you change things up!), but of course errors and changes do creep in, and stories evolve.

Some of the stories were oral histories that tended to become more magical and fantastic through the retellings. Some of them were tales of warning – don't talk to strangers, for they might be big and bad! – and some of them were myths and legends that had no basis in facts or real-life dangers at all.

Many of the tales told for generations were collected and published in the 1800s and the early 1900s by a variety of people, most famously the German Brothers Grimm. Andrew Lang published fairy tales from around the world, and author Hans Christian Andersen wrote his own (kinder, warmer) stories.

Today is a great day to try to tell a favorite fairy tale from memory. Be sure to use inflection and emotion to give the story life. Use repetition. There is a reason that magical things tend to come in threes, because little listeners love the engagement of knowing at least something of what to expect. Also, repeated phrases help kids participate as they chant along with the story teller.

Of course, it's also a good day to read fairy tales or even to watch fairy tales on videos or DVDs.

Here are some more great ideas for Tell a Fairy Tale Day!

 My favorite story about a literal fairy is "Poppy: The Adventures of a Fairy," by Anne Perez-Guerra.
 One of my favorite Hans Christian Andersen fairy talesis "The Emperor's New Clothes."
 One of my favorite stories collected by Andrew Langwas "The Twelve Months."
Here's to a happily-ever-after kind of day!

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