Linburg,+Jebidiah

The article I read was about how the rocket boys created homemade rocket propellants in the movie October Sky. I learned how easy it is to create rocket fuel from homemade materials. Many of the chemicals are either found in most homes or available cheap online. In order to prevent explosions I will probably stick with safer propellants such as compressed air and store-bought rocket engines. Overall I thought it was very interesting.

Jeb, Wise choice. Elaborate on the types of chemicals you are referring to. I wonder if store-bought rocket engines were available at that time? MW

Distillation of crude oil
I was surprised that Oil can be distilled like water and alcohol. I always thought it was filtered and chemicals were added to the mix to make gasoline. How is getting a flame that close to pertoleum products not dangerous? I also learned that diesel, gasoline, and other oil based products boil off of the crude at different temperatures. Once again I thought different chemicals were added. Jebidiah, Oil fires and refinery fires do happen and they are terrifying. Good thoughts! 5 stars! MW

Redefining the kilogram
I think that the kilogram should have the current physical standard converted to a chemical standard. Then scientists should maintain the physical mass so it stays consistent to the chemical standard. The physical representation should be the official measure and the chemical standard would maintain that physical standard. I honestly don't understand why scientists freak out over a few micrograms of decay on a such widely copied standard such as the kilogram. I did learn that every other standard of measure was based on a scientific constant.

Jebidiah, A few micrograms could make a big difference is something like a computer chip. 5 stars. MW

**Where do** elements come from
I learned that all elements are formed in stars. I thought before that elements could combine in space at high speeds. I also learned that iron is the most stable element. I never realized that a neutron was an electron and a proton. It makes sense that a neutral particle would be half positive and half negative. I still wonder how scientists can fuse elements together in a lab. I can't imagine thaProxy-Connection: keep-alive Cache-Control: max-age=0 oxy-Connection: keep-alive Cache-Control: max-age=0 20the large hadron collider is as powerful as a star. I also learned that radioactive elements can 'gain' protons and electrons by losing neutrons.

Jeb,

Looks good. A bit late though. 4 stars. MW

Mole day
I learned that Avagadro didn't invent Avagadro's number. Another scientist created the actual number and he got the credit. How did they count it anyway? I couldn't find that on the mole day site. 6.02*10^23 is way too large to actually count even with a computer. Even for the fastest computer in the world it would take 2 years+ to count that high. Atoms are also too small to count with any accuracy. It is a good idea to be able to count that high quickly, but it seems that counting that high would be laden with error.

Jeb, I think it's an extrapolation from a smaller number but am not really sure how it was determined. 5 stars. MW

Dust Explosions
I learned that almost any substance that is combustible when a solid is explosive as a powder. Many dust explosions have occurred when the proper stoichiometric ratio of dust and air is achieved any small spark could set it off. The first small explosion stirs up more dust creating an even bigger explosion. The explosion often travels throughout the entire plant. As with other explosions, dust explosions are very dangerous. Many injuries and deaths occur from dust explosions every year. I think that companies should do routine cleaning of dust in order to prevent explosions.

Jeb, It's amazing how many things can be extremely flammable when mixed in the right proportion with oxygen. 5 stars. MW

Sulfur Hexaflouride
I learned a lot from this article about gases in balloons. I learned that SF6 in a balloon will actually grow in size rather than shrink. I also learned that when breathing in helium or sulfur hexaflouride your body doesn't make you gasp for air. I always thought that gasping for air was because of a lack of oxygen not an abundance of CO2. SF6 is also a very stable molecule, something else this article taught me. I really enjoyed this article and learned a lot.

Jeb, OK, but what did you already know? This is a bit late also. 3 stars. MW

Motion Detectors
This article makes me remember my electronics class where we had to build IR navigating robots. We had to figure all of this out on our own in order for the robots to work. In the class there was a representation of all three methods. Therefore I already knew the three detection methods, that glass isn't transparent for infrared light, and that different uses need different methods. I learned about the "steel ball" analogy. That helped me to understand energy in light. I also learned that Mr. Hertz was the first person to study the electromagnetic spectrum. The last thing I learned was that a bright light doesn't necessarily mean more energy.

Jeb, Cool beans! 5 stars. MW