These days any weather report worth its salt will include the UV index number. I think we all understand the practicality of it. The higher the number, the higher risk of sunburn. But personally, that superficial understanding doesn’t satisfy my curiosity.

I also get to brag a little, as the UV Index in a Canadian invention, circa 1992. Many other countries picked up on the idea. It’s now been taken over and standardized by the World Health Organization.

We’re talking about ultraviolet radiation here, which got a mention last week regarding its spot on the spectrum of electromagnetic waves. There are three types of UV radiation, conveniently called UVA, UVB, and UVC depending on the wavelength. Each one affects us differently.

UVA: These are the longest waves, and thus can more easily pass through stuff. As such, nearly 99% of all UV radiation that gets through the ozone layer is UVA. UVA causes immediate tanning, and long term wrinkling and skin aging.

UVB: While making up only 2% of ultraviolet radiation reaching earth, this is the bad guy. The cause of skin cancer! Last year I wrote about how a sunburn modifies your genes!

UVC: Our ozone layer pretty much completely blocks UVC radiation from reaching us. Let’s hear it for the ozone, ladies and gentlemen!

Now, the UV index is a rating of how much UV radiation is hitting the earth on a given day.It’s calculated based on a number of factors specific to your area.

1. Sun height – Midday in mid-summer would have the sun looking straight down on you, meaning the least amount of atmosphere between you.
2. Latitude - Your position on the globe affects the angle of the sun.
3. Cloud cover – Well that seems obvious!
4. Altitude – The higher you are, the less atmosphere to protect you. Being 1000 meters above sea level equals a UV increase of about 10%.
5. Ozone – The ozone fluctuates, so it can be absorbing more or less UV on any given day.
6. Ground reflection – Depending on the colour and surface, you could be getting UV bounce-back. Snow will reflect 80% of UV waves.

At night, in the dark, the UV index would be zero. While there’s no upper limit to the scale, 10 would be “extreme”… blue sky, mid summer, sun directly overhead.

I’ll wrap up with a note about sunscreen. Specifically that big SPF number on the bottle. You may know it means Sun Protection Factor. That number is determined with a simple lab test.

They round up some pasty looking people and test how long it takes for their bare skin to burn under a controlled dose of UV light. Then they apply the sunscreen to another patch of skin, and measure the time to burn again. If the original burn happened in 3 minutes, and the sunscreened burn took an hour, that means the natural skin protection increased by a factor of 20. (3 minutes x 20 = 60 minutes) Thus, it gets labeled as Sun Protection Factor 20.

• Source: Ultraviolet Radiation – World Health Organization
• Source: Ultraviolet Index – Wikipedia

P.S. The illustration above was inspired by the random words found in robot-proof captcha security things. (where they ask you to decipher a blurry word… in my case “climate iseight”) Captcha Art is kind of an in thing to do these days. The drawing then reminded me I’ve been wanting to do a story on the UV index for a while.

Related Facts

• FACT: the so-called global warming crisis is a lot of hot air
• Superman, hamburgers, and the Coriolis effect
• Name That Cloud

In 1638 Galileo Galilei, who is called the Father of Science, published the Square-Cube Law. Frankly, it’s not particularly clever as scientific discoveries go. It’s an observation that big things are bigger than small things. However, the particular way in which objects scale does create a few interesting implications.

I’m going to explain the concept using Jell-o. Alright, so imagine a perfect cube of that fruity lime-flavoured gelatin dessert sitting on a plate. Let’s say the cube is 1 inch in all directions. But, seeing as how there’s always room for Jell-o, you say you want “twice as much”. So, you would be expecting a cube that is two inches tall. Twice as much, right?

Not so! It may be twice as tall, and twice as wide, but the other measurements of size have more than doubled. The surface area has been squared, and the volume has been cubed. (hence Square-Cube Law) So, going by the volume, you actually have eight times more Jell-o in a 2-inch-sized serving as you do in a 1-inch-sized serving. A serving 4 inches across would contain 64 times as much Jell-o!

This exponential growth puts a hard limit on how big your Jell-o serving can get before it overwhelms the structural integrity of gelatin. As the volume increases, so does the weight of all that Jell-o pushing down on the bottom-most layer. (the mass is growing faster than the footprint, so the pressure increases) If you visualize this growing cube on your dinner table, you can picture it begin to bulge and eventually crush itself into a gooey mess.

This same law puts a limit on the size of land animals. It explains why ants can walk around on spindly little legs while lifting 50 times their body weight, compared to elephants with their tree-trunk sized feet who would strain to lift a quarter of their mass.

It also affects more than the size of animals. Elephants are practically naked (compared to most other fuzzy-haired mammals) because they have significantly more inside (volume) relative to their outside (surface area) and have a much harder time cooling down their body temperatures. Maximizing the surface area for cooling also explains the big floppy ears and wrinkly skin, which can expel more heat than a smooth surface.

It also explains why the Nazis failed when trying to build a massive tank, and why our giant friend Robert Wadlow needed leg braces to walk. Oh, and why an elephant might die if it could only jump, while a mouse could safely fall off a building. And lastly, if not to beat a dead horse, it explains why Goliath probably wasn’t ten feet tall.

• Source: Galileo’s Square-Cube Law – DinosaurTheory.com – which is just the introduction to the rather curious problem that huge dinosaurs seem to contradict the law. I’m not done reading the whole theory on that website, but so far it’s quite interesting!

Related Facts

• The Shape of the Universe (part 1): the Hypersphere
• What is Light made of?
• The Wide World of Electromagnetic Wavelengths

Last week I was writing about Goliath, the giant of biblical renown. The earliest records mark his height at 6 and a half feet, while later stories (including the Old Testament bible) report him being just shy of ten feet tall.

I had commented that the average height was shorter then, so being over 6 feet might very well be gigantic, relatively speaking. Well, now I’m doing the follow-up to that. Just how tall have humans been throughout history?

As it turns out, the answer is remarkably un-dramatic. Currently, the average height of men worldwide measures in at 5 feet, 9 inches. Turn the clock back 1000 years and the average height then was… [suspenseful organ sound] …5 feet, 8 inches. So in the last 1000 years we’ve grown an inch? Not quite. In around the 1600′s when our health and sanitation hadn’t yet caught up to the size of growing cities, human height was averaging 5 feet, 5 inches.

So we’re looking at a general fluctuation of maybe 5 inches per millennium. Not too exciting. Now let’s talk about some notable exceptions!

The tallest man… ever! Robert Wadlow was measured at 8 feet, 11 inches. He died in 1940, at the age of 22. Being ridiculously tall does seem to affect your lifespan. The average age of people over 8 feet is 43 years. (not counting two gentlemen still towering among us) Biologically, the human body runs into a lot of problems at that size, which seems to cast some doubt on Goliath pushing 10 feet and still being an able-bodied warrior.

Now, I find it rather amusing that there is a speck of physical evidence in support of the biblical height claim… but it comes from our ape ancestors. The Gigantopitecus blacki is an ancient species of ape discovered in southern China. All that has been found is a jaw bone and a few teeth, but they are huge! Some very smart people have been working on this, and by comparing the size of the jaw to its nearest related species the whole ape is speculated to be 10 feet tall. It’s a real-life sasquatch!

There are plenty of other stories of giants. Many claim “hearing about” giant skeletons found around the world, but in every case… every single case… the bones were either A) secreted away by some un-named government organization, or B) mysteriously lost. And for science, frankly, that just won’t do.

• Source: Historically Tall – The Height Site
• Source: Gigantopithecus blacki

Related Facts

• Year At The Museum
• Was Ivan the Terrible really just misunderstood?
• The Suspiciously Sweet Justice of Aspartame

After losing a little belly this summer, I’ve become more aware of my belt. It’s about an inch and a half wide, made with fairly thick “genuine” leather, and a heavy steel buckle. I would estimate it to hold over 200 pounds without any trouble. The phrase “swatting flies with a sledgehammer” comes to mind. Why on earth do I need such a heavy-duty strap for the rather pedestrian duty of cinching my trousers in a bit?

I wanted to figure out how this over-qualified leather belt came to be accepted as the right tool for the job.

From the bronze age right through to the start of the 20th century, belts were almost exclusively tied to military uniforms. While they sometimes came into function as a strap to hold a sword’s scabbard, they were very often employed strictly for fashion. In modern history, from the Crimean war through to Word War II, tight form fitting belts were used as part of the uniform design to emphasize broad shoulders and protruding chests to look more intimidating. (many officers in the Crimean war were said to wear corsets to further shape their figure)

In the civilian world, belts were rarely seen. Suspenders (also known as braces) were the popular choice for keeping your dignity in place. Even cowboys liked their suspenders until Hollywood came along. The whole idea of the large shiny belt buckle first appeared in movies before taking it’s place in real life cowboy culture.

Belts came into favour when “the boys” came home from the war and brought that piece of the uniform with them. Combined with a lowering of the fashionable waistline, the belt took its place on top of the “pants-keeper-upper” podium.

So, it seems there’s absolutely no good reason why I’m wearing such a clunky belt for a job that could be easily accomplished with a length of yarn.

Bonus fact: In my research I also learned about the origin of the questionably fashionable trend of having your pants almost falling off, hanging halfway down your bum, called “sagging”. Turns out, that little fad came from the prison scene where inmates weren’t allowed to have belts for safety reasons. Of course, we all know prison inmates are just the sort of folks we all want to emulate, so it became a hot look.

• Source: Belt – Wikipedia

Related Facts

• FACT: the necktie was inspired by 17th century Croatian soldiers
• FACT: modern hair spray was made possible by the US Army
• How Clowns Use Eggs to Trademark Their Face

I like to think I’m really in tune with my readers, and I know, without you even having to ask, what you really want to learn. You’re probably thinking, “Hey Ryan, if we all get together on this we could probably bring back some words that have been lost to time.”

Well, dear reader, you’re absolutely right. Here’s some dusty old gems to work into your everyday conversation.

Chittyfaced – A gaunt, slim face that might be associated with not getting enough to eat. “You’re positively chittyfaced, my dear! Here, have a meat pie.”

The word derives from a ballad about the monster named Chichevache. (in Olde English, chiche = starving, vache = cow) You see, Chichevache’s diet consisted solely of “patient housewives”, and as such he was constantly starving due to lack of available food.

Rigadoon – A lively dance, particularly referring to the feet. The Scottish variation was Rig-adown-daisy which referred to a dance that, if done in a field, would trample the daisies. “Hold me closer tiny rigadooner.”

This may have been corrupted from the name Rigaud, who might have invented the dance, combined with the Italian donzella for dance.

Further research reveals that in the 1980s there was a line of puppets, no doubt inspired by the Cabbage Patch Kids, called the Rigadoon Gang

Inveigle - To be hoodwinked or blinded, in terms of deception. “Bullwinkle was inveigled by Natasha’s sensual charms.”

The in is not a prefix here (there is no plain viegle) because this is an anglicized French word, aveugler, with the same meaning. It was written as far back as 1547.

So there you go, add a little Olde English flavour to your emails this week.

• Source: “Folk-etymology” on Google Books – circa 1882

Related Facts

• Year At The Museum
• Who put the polka in the polka dot?
• Try not to enjoy eating fish too much… or else!

Yesterday as I was writing an overview of Electromagnetic waves (which manifest as radio, heat, light, and more depending on the wavelength) but I left myself with the question of what “stuff” makes up these waves. As I discovered, I can give you two different answers that are, apparently, both correct.

Now, just a quick catch-up for those who missed yesterday’s class: Visible light is but a very small section of the electromagnetic spectrum. The different colours of the rainbow are created by a difference in the wavelength of the electromagnetic wave. Violet is the shortest, while red is the longest wave. These very same electromagnetic waves can get longer to become invisible heat (infrared), or radio waves. On the other side, shorter waves turn into ultraviolet radiation, x-rays, or gamma-rays. It’s all the same stuff, physically, so now I’m trying to figure out what that stuff is.

The original answer defines light strictly as a wave. The wave is created as an electric field interacts with a magnetic field. The wave can travel endlessly through this electro-magnetic field, which exists throughout the universe.

You’re not the only one who thinks that does a pretty poor job of explaining anything. Einstein, Planck and other scientists felt so unfulfilled by that answer that they formulated the whole concept of quantum theory. In that light is not a wave, but rather particles full of energy called photons that can travel at the speed of light. A burning fire would then be emitting photon particles in every direction, and the energy contained in a photon would replace the defining wavelength as the means of determining whether each photon would be the visible orange glow, or the infrared heat.

It’s still not a solid answer to what is the stuff of light, since photon particles have no mass. There’s nothing there, other than “energy”, which could take us on a similarly confusing path to figure out just what energy is. I’ll pass on that one, thanks.

To add insult to injury, there’s a little thing called wave-particle duality, that shows by experimentation (meaning it’s not just some crazy idea, it can be observed) that light is both a wave and a particle. Not that sometimes it’s a wave and sometimes it’s a particle, but in fact that light is both a wave and a particle simultaneously.

At this point, I’m going to simultaneously throw my hands up and give in. It seems I’m not quite ready to understand what light (or any electromagnetic wave) really is in a tactile sense that I can wrap my head around.

To offer a little comfort, I did find this quote from Richard Feynman, who was always very good at explaining things to everyday folks like us:

“We choose to examine a phenomenon which is impossible, absolutely impossible, to explain in any classical way, and which has in it the heart of quantum mechanics.” – Prof. Richard Feynman

• Source: What Is Light? – ThinkQuest
• Regarding wave-particle duality, here’s a good animation explaining the oddness of the “dual slit experiment” (YouTube video)

Related Facts

• The Wide World of Electromagnetic Wavelengths
• The Shape of the Universe (part 2): Infinity and Beyond
• The Shape of the Universe (part 1): the Hypersphere

Question: What do the following things have in common?

• Hearing an ad for “Armor Hot Dogs” played over the radio.
• Cooking some hot dogs in the microwave oven.
• Roasting hot dogs over a campfire.
• Seeing mustard stains on your shirt from that hot dog you ate.
• Tanning on the beach after going to the hot dog stand.

The answer: They are all the result of Electromagnetic Waves! (oh, were you distracted by the hot dog references?)

Radio waves, Microwaves, Infrared waves (what we feel as heat), Visible Light waves, Ultraviolet waves… plus the mysterious X-ray waves, and Gamma-ray waves. Each and every one is an electromagnetic wave. Though each can do very different things, the only difference between them is the wavelength.

So what is wavelength? Really it’s about as simple as it sounds; it’s the length of a wave. If you think of ocean waves there are high spots (peaks) and low spots (valleys). If you measure from peak to peak you would have the entire length of one wave.

Some example wavelengths:

• AM Radio Station ~ 300 meters
• FM Radio Station ~ 3 meters
• Microwave oven ~ 1 foot
• Radar ~ 5 centimeters
• Body heat ~ 10 micrometres (micrometre = 1 millionth of a meter)
• The colour blue ~ 0.5 micrometres
• Sunburn inducing Ultraviolet ~ 30 nanometres (nanometre = 1 billionth of a meter)
• Gamma rays at the far end of the spectrum go beyond 0.003 nanometres across.

In the same way that a mountain and the beach are made of the same thing, sometimes size does matter.

Now hold on just a minute, buster! I have a question. Waves don’t really exist as a physical thing. It’s just a method of movement. I understand a wave of moving water, but what is a wave of electromagnetism? I mean, what “stuff” is moving?

Well, all electromagnetic waves move at the speed of light. The fact is, they are light. Or more accurately, light is them. So to answer what is an electromagnetic wave, you have to answer what is light?

That’s such an interesting question that I’m going to save it for next time.

• Source: NASA explains Electromagnetic Waves to Kids (or anybody else who wants a basic understanding)

Related Facts

• What is Light made of?
• The Shape of the Universe (part 2): Infinity and Beyond
• The Shape of the Universe (part 1): the Hypersphere