Miljevic,+Djordje


 * 1/21/10 Tattoo Ink:**

Tattoo ink can relate to Chemistry because the ink is a heterogeneous mixture made of minerals which together form the different pigments. For example, black ink has iron oxide or carbon in it, while white ink has titanium dioxide, zinc-oxide or lead carbonate in it. There is a new tattoo ink made by Freedom-2 that is easier to remove. This new pigment plus a material to help the skin better absorb the pigment are put into a translucent polymer bead. This bead/ink is applied to the skin, and because it absorbs easier, the person is exposed to less pigment. It only takes one laser treatment for the polymer bead to be safely broken down so the pigment can be reabsorbed into the body, making the tattoo disappear.

George, Good job! You write well. 5 stars. MW


 * 1/22/10 Distillation of Crude Oil:**

Crude Oil can relate to Chemistry because it needs to be separated into different compounds. The way this is done is by distillation. The 5 different fractions in crude oil have different boiling points, so different temperatures will produce different separated substances. Crude oil, a homogeneous mixture, straight from the ground is useless to people unless it is refined. The oil industry uses factories to distill crude oil on a large scale. They connect crude oil pipelines to huge heating towers which heat from 300 degrees Celsius at the bottom all the way to 85 degrees Celsius at the top. This way they collect all the different substances in crude oil, which are separated by different boiling points pipes along the towers.

George, Well done! 5 big stars.


 * 10/27/10** **Redefining the Kilogram:**

Redefining the kilogram didn't seem like a big deal to me but, to scientists it is crucial to the way they measure mass. I didn't know that there were two constant values that determined the exact mass or weight of a kilogram. One was Planck's constant which deals with mass, the equation being frequency=maProxy-Connection: keep-alive Cache-Control: max-age=0 *(speed of light) ^2. The other was Avogadro's constant which is the number of atoms in 12g of 12C (one mole). Scientists want to change Avogadro's constant to Avogadro's number, which would help students better understand moles and how they relate to mass. So in relation to chemistry, redefining the kilogram, a measurement of mass, could also help me better understand another measurement of mass, the mole.

Djordje, Good point!! 5 stars. MW


 * 2/25/10 Where do Chemical Elements Come From:**

The chemical elements article relates to chemistry because it shows where chemistry's roots, the elements, came from. The amazing supernova explosion creates many key elements like hydrogen, helium, carbon, oxygen, manganese and iron, which is the heaviest and is in the nucleus of the star. The star can also create elements heavier than iron by absorbing neutrons before explosion or over time with a "slow" phase and with a "rapid" phase, which absorbs neutrons during the explosion. The death of a star is a sacrifice but it releases precious elements needed to create new life.

Djordje, Interesting comment. Life could not have occurred without sacrifice. Very philosophical! 5 super stars! MW


 * 3/11/10 Mole Day:**

Mole day relates to chemistry because it is Avogadro’s number. It interesting how the measurement of the mole evolved. In 1811 it was just a hypothesis by Avogadro, in 1827 Robert brown related it Brownian motion, in 1860 Cannizarro developed his weights base on 1/16th of an oxygen atom. Millikan had an oil experiment that improved the accuracy in the early 1900’s but not until 1958 that it was found that the mole is 6.02*10^23. Without this progressive accuracy of the mole, we couldn’t really calculate how many atoms are in an element accurately, as well as calculating the amount of each subatomic particle in a mole of atoms. We wouldn’t be able to get molar masses to calculate how much of an element it would take to react with something else either. Above all, Chemistry measurements would extremely confusing without the mole.

Djordje, Wow!!! Excellent post! Very scientific. 5 molerrific stars.


 * 4/07/10 Dust Explosions:**

Dust explosions relate to chemistry because they are very deadly chemical combustions/reactions. The smaller the dust particles the less energy it takes for them to combust. This is because smaller particles have a higher surface area to weight ratio, which gives flames a larger area to “catch” on. It takes very little to set off a dust explosion off, only a 1/8 inch coating of dust and a small spark or electrical current are required. One small explosion lifts the dust from the ground and this lets flames from one explosion catch onto the risen dust in the air creating a chain reaction of explosions, somewhat like a chain reaction car crash.

Djordje, Good analogy! 5 stars! MW


 * 4/26/10 Helium Balloons and Sulfur Hexafluoride:**

In the article, I knew three things prior to reading it, but I also learned three things while reading it. I knew that sulfur hexafluoride was the stuff you used to make your voice lower because Mr. Williams mentioned it in one of his lectures about compounds. I knew that that helium balloons decrease in size over time and that a balloon filled with air would maintain its size longer because of my experiences. I learned that a sulfur hexafluoride balloon would grow in size because the particles of air rush into holes faster than it can escape. I learned that because sulfur hexafluoride’s polar bonds are symmetrical, the bonds cancel out and create nonpolar molecules. I learned that when breathing in sulfur hexafluoride, you are not actually breathing in oxygen, which then suffocates your blood with carbon dioxide.

Djordje, That bit about SF6 being symmetrical is a key idea! Well done. 5 helios! MW


 * 5/7/10 Motion Detectors:**

In the article, I knew three things prior to reading it, but I also learned three things while reading it. I knew light detectors detect objects that pass through the space of the beam blocking the light and thus setting it off. I knew sound detectors sent out wave pulses that monitor sound patterns going off if the pattern changes. I knew infrared motion detectors gave off infrared signals monitoring infrared radiation around it going off if a change of heat quickly occurs. I did not know that a photo sensor greatly depends on light’s capacity to push around electrons. I did not know this push was “photo electric current”; meaning when light hits an object it causes electrons to eject. I did not know that high intensity low frequency waves could not move these electrons but low intensity high frequency beams could.

Djordje, Good call. Yes the frequency effect is pretty cool! 5 stars! MW