Have you ever seen a t-shirt that changes colour when it is in direct sunlight? Or perhaps new colours become visible? Maybe you have some of those fancy prescription glasses that become tinted sunglasses as you step outside.

All that falls under the name Photochromism. Photo being light, and chromo being colour.

It’s a minutely complex chemical reaction that occurs in the presence of electromagnetic waves in the ultraviolet region of the spectrum. That is to say, UV light. When those UV waves hit the photochromatic substance, the chemical reaction occurs that causes a change in its ability to absorb visible light.

Now, here at LSNED I always try to take the hardcore science and boil it down to a casual explanation that makes sense. Just so you’re aware of my struggle, here’s the source material on this…

The conjugated system of the oxazine and another aromatic part of the molecule is separated by a sp³-hybridized “spiro” carbon. After irradiation with UV light, the bond between the spiro-carbon and the oxazine breaks, the ring opens, the spiro carbon achieves sp² hybridization and becomes planar, the aromatic group rotates, aligns its π-orbitals with the rest of the molecule, and a conjugated system forms with ability to absorb photons of visible light, and therefore appear colorful.

So, umm, to summarize, err… well… so every thing in the universe is made up of the same building blocks, as seen on the Periodic Table of the Elements. The difference between your eyeball and the computer screen you’re looking at is just a different arrangement of those basic parts. In the case of our colour-changing dye, the sunlight actually rearranges the physical bonds between the parts, and that teeny-tiny change makes for a dramatic and visible shift in the objects properties. Just like your eyeball, if the parts suddenly got scrambled, could end up being a potato dumpling.

When it comes to glasses that turn into sunglasses as you step outside, that chemical process is a little bit different. When they make the lenses, they add two special ingredients. Silver chloride and copper chloride. When that same UV light hits the silver chloride it oxidizes, or “rusts”. That throws the physical arrangement out of whack and leaves us with a pile of leftover electrons, which find new homes with silver ions to create new silver atoms that block some of the incoming light, making the glasses seem darker.

It might stay that way for a ling time, if not for the copper chloride that was also added into the lens. Like an atomic groundskeeper, the copper chloride not only keeps the stray chlorine from escaping the lens, but it reduces and re-sets the chemical change as soon as the UV light has faded away. The tinting process is reversed, and set to go again.

Personally, I find chemistry to be the most mysterious thing in the universe. I tend to have a logical grasp on the concepts of physics, but chemistry still seems like magic to me!

• Source: Photochromism – Wikipedia
• Source: Photo-oxidation – Photochromic Glass – University of Hawaii (if anyone should know sunglasses…)

Have you ever seen a photograph that makes the world look tiny? Even through you know it’s real, you can’t help but see it as a close-up of a miniature model train village in a retired-person’s basement. Have a look at this video of my city, Calgary, to see the illusion in action.

“Moving Calgary” video by Charlie Su. Watch on YouTube

Pretty neat, yeah? Charlie is not a retired man painting plastic people in his basement… not yet anyways… but a photographer who likes spending time on rooftops. All that footage is the real deal. So what makes it all look so cute and tiny?

That’s the diorama illusion, and it’s your brain playing tricks on you. Sometimes this illusion is mis-called the “tilt shift” effect, as a tilt-shift lens (a special moving lens for a camera) is one of the tools that can be used to create the illusion. However, most of the videos and photos you see with this illusion are created with digital effects. It’s surprisingly simple!

The key to the whole illusion is the blurry parts of the image. Watch the video closely. Notice how the edges of the screen are always blurry, and only a small area of the picture is in sharp focus. Photographers call this the depth of field. Whenever you look at something, any objects that are closer or farther from your eye will be slightly blurred. The further from your area of focus, the more blurred they are.

If you look out the window at things far away pretty much everything appears more or less in focus. You can see the whole landscape at once. Now, hold something up near your face and focus on that. Suddenly everything behind it becomes very blurry in your peripheral vision.

Your brain has a good understanding of the connection between blurriness of objects and their relative size and position to you. Far away, everything is in focus. Up close only small parts are in focus. It’s this understanding, or set of assumptions, that your brain has that is being forcefully manipulated to create the illusion.

When the edges of the photo or video are blurred just right, so that the area near the focus spot is blurred a little, and the outer edges are blurred a lot, it tricks your brain into thinking it’s looking at something very close-up.

Add that with the high angle of the photo, looking down from above, and it creates a very strong perception of being miniature. In the video the high-speed movement is just another layer of trickery, making the people look like scurrying ants.

Your brain means well, but it can always be manipulated.

• Source: Miniature Faking – Wikipedia
• Try it! A great tutorial on how to make your photos look tiny with PhotoShop.
• Try it the easy way. You can apply the blur automatically at TiltShiftMaker

I have a friend who teaches a grade six class. Yesterday she began explaining how the moonlight is really just light reflected from the sun, when the whole class erupted into a volcano of curiosity. She couldn’t keep up with all the great questions they were asking, and had them write them all down. She shared some of them with me, and I thought I’d take a stab at answering them.

“What are planets for?”

Well… planets aren’t really for anything at all. They have no purpose. No particular reason for floating around space. When we look at the barren desert of Mars, or the thick clouds of Venus it’s easy to consider our lovely little earth to be a paradise. I think it’s important to realize that there is nothing special about earth. It formed out of chaos and clouds of dust just as randomly as any other planet in our system.

As for why earth has such a lush ecosystem compared to Mars’ red dust… I suppose it’s a bit like baking a cake. When the ingredients are mixed just right, the cake will rise up light and fluffy. If the recipe is too far off, you end up with a dried out lump of floury gunk. If you were mixing cake ingredients in the same crazy way that the planets were formed, throwing them all around and seeing which bowls they landed in, you’d end up with way more lumps of gunk than you would delicious cakes. It doesn’t make that one cake special… it just happened to work out alright.

“How big exactly was the big bang if it is not a theory and it is real?”

The first thing to talk about here is what scientists mean when they call something a “theory”. Sir Isaac Newton discovered his “Theory of Gravity”, but if you drop a rock on your toe it sure does feel real! A theory is another way of saying “I’m pretty sure I know how this works”. Scientists always like to say they are “pretty sure” instead of saying “I absolutely 100% know this is true”. The reason they do that is because other scientists will always be discovering new things that might change our understanding of something. There is always room for improvement and refinement in science.

When it comes to the Big Bang, it’s always been a challenge for astronomers to see what happened so long ago… 13.7 billion years back! It’s a bit like trying to do a jigsaw puzzle when all the pieces have been hidden all over your city. First you have to find the pieces, then you need to fit them together… and all the while you don’t know what the puzzle is supposed to look like!

Now back to the question… how big was the Big Bang? Well, I suppose you could say it was the biggest thing ever. Everything everywhere… planets, stars, galaxies… was all compressed into one little ball and then it exploded. It exploded so big it spread all the pieces (including you and me) all over the universe, which is almost too big to even imagine. It had more energy than our sun and all the stars in the sky. HUGE energy! ALL energy at once!

“Big” doesn’t even begin to explain it.

“How did people get on Earth?”

This is a bit like asking how you got to the town in which you were born. You never really moved there. You just started there from your beginning. Maybe your parents moved to that town from somewhere else. Or maybe it was your grandparents that first arrived. To find out how humans got here we need to go way back. Way way back. All the way back to that Big Bang thing.

You see, you and I are made up of tiny parts, atoms, just like everything else. At one point all these atoms were part of that Big Bang. Hydrogen and helium atoms were thrown across the universe, and they started combining and mixing into more complex things like carbon and oxygen. If we fast forward about 10 billion years, the cloud of dust, made up of those same original atoms, begins forming into the ball we lovingly call Earth. Fast forward another 2 billion years and some of those atoms just so happened to “bake a cake” and rise up as the first single-celled organisms. A living thing on an otherwise dead rocky planet.

Jump ahead 4 billion years and those single cells have fought and clawed their way (or, at least once they grew claws) to grow into animals and plants. It’s always just a new way of arranging those atoms. Some of those animals became dinosaurs about 300 million years ago. Other animals became mammals somewhat like a mole. Those mammals kept adapting and changing over the millions of years until about 25 thousand years ago our ancestors popped up in the mix. Those early humans kept on growing, becoming smarter and stronger, until… well… here we are.

So we never got here. The stuff that we’re made of has always been here.

Stay tuned for more great questions next time.

• Thanks to: Ms. Hildebrandt’s Grade 6 class
  
• Source: Big Bang – Wikipedia
• Source: Timeline of evolutionary history of life – Wikipedia

Back about 2000 years ago, the Greek scientists were becoming fascinated with magnetism when they stumbled upon lodestones, a naturally occurring magnet.

Lodestone is a piece of magnetite, an iron oxide, which produces a strong magnetic field. Now, to be clear, not all magnetite is magnetic (it won’t stick to your fridge by itself) but being a type of iron, all magnetite is attracted to a magnet (technical word: it’s ferrimagnetic).

The creation of a lodestone (magnetized magnetite) is still a bit of a mystery, but the leading hypothesis is that the magnetic properties were picked up after being struck by lightning. It’s sort of a geological superhero origin story. This theory is supported by the fact that a lodestone has never been found very far from earth’s surface.

The word magnet originates from Magnesia, which was a region of Greece where these original lodestones were popping up.

Magnetite lodestones are one of only two minerals that have been found to be naturally magnetized on earth. Which begs the question; how do the real estate agents and plumbers manage to get their hands on so many lodestones?

Most of the magnets we encounter on a daily basis have been artificially magnetized. You can start with any ferromagnetic material. (most commonly ferrite, a ceramic compound containing iron oxides) The simplest way to turn that into a magnet would be to rub it against something that is already magnetized in the same direction many times. (it’s sort of like you are “combing” the electrons)

To manufacture the strongest magnets, the material must be heated above the Curie temperature, which varies depending on the material, putting it into a receptive state. It’s then subjected to a strong electromagnetic field. As it cools, the magnetism remains in the material. If it’s ever re-heated past that Curie temperature again, it could lose it’s magnetic strength. I learned this the hard way when trying to use a hot glue gun on rare-earth magnets.

Now, this is just the tip of the iceberg for the fascinating science behind magnets. There is a lot to think about next time you go to clip up your grocery list.

• Source: Magnet – Wikipedia
• Good Book: Magnetic Magic – from Klutz Press, I had this book as a kid and loved it. Comes with magnets and a steel book cover to keep them on.

A plane zips across the sky, leaving in its wake a long line of white cloud. There is a conspiracy theory that swears this is the government spraying the world with “mind-control agents” for nefarious means. A little bit of science reveals the truth.

The white line, called a condensation trail, or contrail, is made of nothing but cloud. They are no different than any other cloud in the sky. Just tiny droplets of water that float through the air. These contrails are created behind a jet plane as it literally rips through the sky.

The exhaust from a jet engine spews out a lot of hot air, along with water vapour, soot, and a few other chemicals. As the body and wing of the plane move through the air it creates a lot of turbulence in its wake, like a speedboat moving across a calm lake. As a result the cold air in the upper sky is violently churned with the engine exhaust. It’s this mix that often provides the right environment for clouds to form.

The cold air in the sky causes the warm water vapour to condense into droplets around the tiny particles of soot. If the air around the contrail is dry, it can suck up the moisture like a sponge fairly quickly, and the trail fades away. However, if the air is humid the contrail can be seen as a sharp line across the sky for hours as it slowly spreads out.

It’s actually the exact same process, though on a larger scale, as when you exhale on a clod day and can see your breath. That’s the warm humid air from your lungs condensing as it meets with the chilled outside air.

So that trail is not brain-numbing chemicals. It’s not smoke, or even pollution of any sort really. (Any jet exhaust seems insignificant compared to the number of cars on the road) It’s nothing but a harmless fluffy cloud. Although, there have been some studies asking questions about whether the additional blanket of clouds may be warming up our world.

Questions are good. Questions can be dangerous! Questions can sometimes make governments wish they were spraying mind-altering cocktails in the air.

• Source: Contrails – Cooperative Institute For Meteorological Satellite Studies, University of Wisconsin-Madison

The brightest star that we can see in the night sky has been named Sirius, an ancient Greek word for “glowing”. It’s one of the closest stars to earth, about 8.5 light years away, and we can look forward to it getting brighter for the next 60,000 years as it inches ever closer to us. When the conditions are right, this star can be seen even in daylight.

It was in 1844, however, when this bright pinpoint of light was determined to be a binary star. That means the light we see is, in fact, produced by a pair of burning gas balls so close together that it seems as one. Sirius A is a big bright star, while Sirius B is a tiny white dwarf, which is a late stage star that has nearly burnt out and collapsed into a super dense ball. A teaspoon of white dwarf star material would weigh about the same as a locomotive.

The two make up a binary star system because they orbit around each other at about the same distance as Uranus orbits around the Sun. That’s close enough to be tangled up in each others gravitational fields. Some binary stars are so close that they actually pull on the gas like the moon pulls on the ocean tides. Matter is ripped free of it’s gravitational bonds creating a stream of “star juice” between the two masses.

Thanks to Kepler’s Laws of Planetary Motion physicists have been able to look at the orbits of binary stars, which from our viewpoint is little more than a wobble, and reverse engineer the precise details of their mass and density. Combining that with a stars spectral signature, the peculiarities of the light it radiates, we’ve been able to learn a lot about the composition of stars twinkling from afar.

With improvements in both our telescopes and our understanding we’ve been able to determine that approximately 85 % of the stars in our own neighbourhood, the Milky Way galaxy, are binary pairs, or even larger multiple star systems. It seems our Sun is the odd one out, all by its lonesome.

Be nice to our Sun. After all, we’re made of the same stuff.

• Inspired By: Alan Dyer’s amazing book, STAR: From Birth to Black Hole
• Source: Astronomy 222 Lecture Notes – University of Oregon
• Source: Sirius – Wikipedia

Alas, it has been a while since I’ve written a new LSNED article. There are only 24 hours in a day, you know!

Twenty-four seems like an arbitrary number to choose for hours in a day. Consider that somebody along the way had to decide how long an hour was, and how many could squeeze into one day. So just where did the number come from?

It appears the Egyptians are the architects of our daily scheduling. In ancient times, their numbering system was based on 12, just as ours is based on 10. It is believed they learned to count using the joints of their fingers (three on each finger) making 12 the natural sized group. Frankly, that’s no more strange than how we now base everything on 10 because we have ten fingers/thumbs.

Any way you count it, the Egyptians loved their twelves, so they opted to decree there were twelve parts to the day, and twelve parts to the night. For a long time, these twelve parts would stretch and grow throughout the year as sunlight varies with the seasons. It was the Greek mathematician, Hipparchus, who first set about trying to standardize the time periods, but this was not widely practiced until the 4th century.

The word hour began as hore or hora, but the H has fallen silent since early Roman times.

If you’re hoping for more LSNED’s, I suggest you poke back into the archives with this article on clocks that let you smell the time. And next time you complain about not having enough hours in the day, at least know you know who to point your triple-jointed finger at. Yes indeed, we all… clock like an Egyptian.

• Source: Curious About Astronomy – Cornell University
• Source: Origin of the word Hour – Online Etymology Dictionary