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Archive for January, 2008

Straws

Well, it’s been an…interesting weekend.  While trying to be productive, I began researching the LifeStraw® because my partner and I clearly need a new debate case.  Basically, the LifeStraw® is a sort of cheap purification tool that removes microorganisms responsible for causing water bourne illnesses (like diarrhea, the 2nd leading cause of death in Sub-Saharan Africa!) from dirty water when you ‘suck’ it through the straw. 

LifeStraw

And that, folks, is the background info on this week’s blog entry, straws!  So, when you’re drinking with a straw, you’re not actually ‘sucking’ in the water/soda/juice/mysterious liquid.  You’re really removing the air inside the straw, making the air pressure in that space lower than 101.325 kPa.  The water column near the bottom of the straw experiences a pressure imbalance (higher pressure on drink and lower pressure in mouth) that provides an upward force, pushing the liquid up the straw and past a horrifying set of teeth.  Just kidding about the last part. ; )

drinking-straw.jpg

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After arriving back in Oahu Sunday evening, I had a restful sleep for the first time in two weeks.  Naturally, I didn’t wake up until Monday afternoon (16 hours of sleep!) and I probably could have slept until Tuesday morning if I didn’t have homework to do…

Anyways, I really didn’t feel like doing anything strenuous today so I decided to…paint my nails!  Rather random but I’ve been wanting to try out that Del Sol nail polish I got as a Christmas present for a while.  The color’s called ‘Ruby Slipper’ since it’s a shimmery silver indoors but turns into a pinkish red color outdoors.  Interesting yes?

So I did some research (not on Sub-Saharan Africa for a change) and discovered that Del Sol has its own special Spectrachrome® color-changing crystal.  As we kind of learned in eight grade science, the color we perceive an object to be depends on the spectrum of light leaving its surface.   Humans can see colors when the wavelength of the electromagnetic radiation is from about 380 -740 nanometers.

Upon irradiation by ultraviolet waves (sunlight), the Spectrachrome® crystal undergoes an activation shift called a “molecular excitation transition” that makes the color of the dye suddenly visible.  It probably does something to the wavelength of the electromagnetic radiation…

ruby-slipper.jpg…I need more sleep. ~_^

Happy Third Quarter!

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Zeus

Remember a long, long time ago when I wrote a teensy little bit about lightning?  Of course you don’t.

But seeing that we’re now studying electric charge, I will in fact expand on that ancient post.  Electrons flow from negatively charged objects to positively charged ones and lightning is an example of this.  Lightning transfers a very large amount of charge from a cloud to another cloud or to the ground. 

During this, the overall charge of the system is kept constant even though the cloud itself is now electrically neutral.   A bolt of lightning contains about 23C of charge and heats nearby air to about 10,000°C.  With all that technical stuff aside, lightning is just awesome to see. 

I know I had a better mini-video of lightning somewhere…the one below is horrible since it was taken with a cell phone camera. :/  You can’t even see anything unless you don’t blink for half a minute and stare with your nose pressed up against the screen…so I suggest you don’t try at all.

Instead, I shall supply you with a lovely picture off the web!

lightning.jpg

Happy sleepless exams/debate week!  At least you have an unlikely chance of being struck down by Zeus. : )

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Thermometers!

Since we’re now studying heat and temperature, the thermometer is the perfect object to examine.  Thermometers are of course used for measuring temperature.   This is possible because two objects placed in contact with each other will eventually reach a common temperature.

thermometer!

The old glass thermometers most of us are familiar with are usually filled with mercury.  Mercury expands with rising temperatures and contracts with cooling temperatures. Changes in temperature will cause proportional changes in the expansion/contraction of mercury, which allows us to “read” the temperature off of the little tube with reference points and numbers.  ^ ^

In daily life in the U.S., you’ll probably find yourself expressing the temperature in °F.  Besides the Fahrenheit system, there are also the Celsius and Kelvin scales, much more commonly used in the rest of the world.  Luckily, conversions between the systems are quite simple with the following equations. 

TK = TC + 273.15

TC = (5/9)(TF − 32)

Tonight’s forcasted temperature in my area was 73°F, which is approximately 22.3°C or 295.9K.

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