Notifiblog: How Stuff Works Thursday!

​I've been so busy, I've been neglectful of Notifiblog. I can't really apologize: I've been busy working at the job someone's paying me to do.

Today's "caught my attention" article from www.howstuffworks.com is 10 Science Questions You Should Really Know How to Answer. Per tradition, Notifiblog looks at the three I like best. Due to limited time, I'm forced to quote direcly from the HSW answer people.

Why is the sky blue? "The reason the sky appears blue is because of an effect called scattering. Sunlight has to pass through the Earth's atmosphere, which is filled with gases and particles that act like the bumpers on a pinball machine, bouncing sunlight all over the place. But if you've ever held a prism in your hands, you know that sunlight actually is made up of a bunch of different colors, all of which have different wavelengths. Blue light has a relatively short wavelength, so it gets through the filter more easily than colors with longer wavelengths, and as a result are scattered more widely as they pass through the atmosphere. That's why the sky looks blue during the parts of the day when the Sun appears to be high in the sky (though it's actually the spot on the planet where you are standing that is moving, relative to the Sun).
"At sunrise and sunset, though, the sun's rays have to travel a longer distance to reach your position. That cancels out blue light's wavelength advantage and allows us to see the other colors better, which is why sunsets often appear red, orange or yellow."

Why are bubbles round? "Well, actually, bubbles are not always perfectly round all the time, as you probably have noticed if you've ever used one of those toy thingies to blow soap bubbles. But bubbles want to be spherical, and if you blow one that's more cigar-shaped initially, it struggles to reshape itself. That's because bubbles basically are thin layers of liquid whose molecules stick together because they are attracted to one another, a phenomenon called cohesion [source: USGS]. This creates what we think of as surface tension -- that is, a barrier that resists objects trying to move through it [source: USGS]. Inside the layer, air molecules that are trapped can't get out, even though they're pushing against the water. But that's not the only force acting on that layer. On the outside, more air is pushing inward at them. The most efficient way for the liquid layer to resist those forces is to assume the most compact shape, which happens to be a sphere, in terms of ratio of volume to surface area [source: Popular Science].

"Interestingly, scientists have figured out ways to make bubbles that aren't round, so they can study the geometry of the surfaces. They're able to create bubbles that are cubical and even rectangular, by suspending a thin layer of liquid on a wire frame that that is molded into the desired shape [source: NEWTON]."

 

How do magnets work? "'[Bleeping] magnets: How do they work?' That's the question that rappers Insane Clown Posse posed in their single "Miracles" a few years back, which led those snarkmeisters at "Saturday Night Live" to ridicule them unmercifully. And that was unfortunate, because it's a perfectly reasonable thing to ponder. A magnet is any object or material that has a magnetic field -- that is, a bunch of electrons flowing all around it in the same direction. Now, electrons -- like rappers from Detroit who wear clown masks, curse a lot, and drink Faygo Cola -- like to hook up in pairs, and iron has a lot of unpaired electrons that are all eager to get in on the action. So, objects that are solid iron or have a lot of iron in them -- nails, for example -- are going to be pulled towards a sufficiently powerful magnet. The substances and objects attracted to magnets are called ferromagnetic substances [source: University of Illinois].

"Humans have known about the phenomenon of magnetism for a long, long time. There are naturally occurring magnets, such as lodestone, but medieval travelers figured out how to rub steel compass needles against those stones so that they picked up electrons and became magnetized, which means that they developed their own magnetic fields. Those magnets weren't particularly durable, but in the 20th century, researchers developed new materials and charging devices that enabled them to make more powerful permanent magnets [source: Stupak]. You can actually create a type of magnet, called an electromagnet, from a piece of iron by wrapping an electrical wire around it and then connecting the ends to the poles of one of those big batteries with the clips on top [source: University of Illinois]."

 

Who knew? Now we do!