Snyder,+Justin

Mentos and Soda: I read the Coke and Mentos article. This really interested me because it is an experiment that I have done numerous times but I have never known why the soda erupts like a geyser. The article explained that the rough, pitted surface of mentos is the cause for the “geyser effect.” In the bottling plant, CO2 (carbon dioxide) is pumped into the bottles at very high pressure, so when the bottle is opened, the soda holds more CO2 than it is supposed to be able to hold. When the mentos are dropped into the soda, the rough surface irritates the CO2 causing the gas to bubble up, exposing more soda to the mentos and ultimately causing the whole thing to erupt completely.

Justin, Keep this one but read one from our list. MW

Lead Poisoning: I read the lead poisoning article and learned that some candies contain lead. Not all the candy in the world contains lead though, mainly only candy that comes from Mexico. Mexican candies use chilly powder (for what reason, i don't know) which contains lead. This is not form the soil but from the process that is used when the chilies are ground up into chilly powder. Sometimes the chilies aren't even washed. Sometimes lead finds its way into the chilies and then it gets ground up along with the chilies. The pots that the candies are stored in pots that are painted with lead paint. Depending on how long the candies stay in these containers, the candies can absorb some of the lead also. As if this weren't enough, the wrappers that the candies are wrapped in have lead in the lettering. These candies aren't sold everywhere though, mostly in the southwest (texas and new mexico).

Justin, OK. Full marks. MW

Crude oil: Crude oil is a mixture of different hydrocarbons. Together the mixture is useless, but separated, they have many different applications. Some hydrocarbons heat more quickly and evaporate more quickly. These are then collected and condensed as a separate part of the crude oil. The longer the molecule is, the higher the temperature must be to heat it up. The shorter molecule chains vaporize more quickly and are separated from the rest.

Justin, Good comment on molecule size. A bit short 71 words. MW

Redefining the Kilogram: After the enlightenment, when science was on the rise, the scientific community created standards so they could keep accurate measurements. The kilogram is the only base unit that isn't "perfect" because it is still defined by a physical object. To redefine the kilogram, they

And...? 1 star. MW

Where do elements come from?: All elements originate from stars, except for hydrogen, whick was created during the big bang. All the other elements were created out of hydrogen in the middle of stars. New and heavier elements are created because the intense heat and pressuer on the inside of a star forces hyrdogen atoms together creating helium. This process is repeated over and over again until it reaches Iron. This process, called the "s" process, stops because when the entire core of a sun becomes Iron, it can no longer tranform into anything else and collapses upon itself, creating a suoer nova. This spews billions of subatomic particles along with elements into the universe which then combine to form even greater elements. Another way elements can be created is by radioactive decay. When a certain element is unstable, it slowly decays until it becomes a different element. This element in turn captures other neutrons and starts the whole process over again. This is how elements are formed.

Justin, OK. Good article review. 5 stars.MW

Mole Day: Avogadro first started his career as a lawyer. He started to take private lessons in mathematics and physics and decided that he would make his career in natural sciences. He was actually a physics teacher but he experimented in physics and chemistry, basing all of his findings on mathematics. Unfortunately, his findings weren’t recognized for over fifty years. He also created the law known as Avogadro’s law. This law states, “At a fixed temperature and pressure, equal volumes of gases contain the same number of molecules.” This law was based off of the findings of Joseph Gay-Lussac who first discovered that all gases, when subjected to an equal rise in temperature, expand by the same amount.

Justin, Good scientific post! 5 stars. MW

Dust explosion: The article was too small to read and it wouldn't zoom in. 4/11/10 I was able to read this article this morning on a school computer so i will now do the entry. Over the past three decades, more and more dust explosions have been occurring. These can be triggered from even the faintest spark and can roll through a factory and decimate everything in its path. Most people so not think that dust or something as harmless as sugar can be explosive, but they would be wrong. The smaller the particle, the more surface area there is and the easier it is to ignite. Also, the smaller particles require less energy to combust. It is this that can destroy an entire factory in minutes. Just half an inch of dust on the floor can be stirred up by an initial disruption that sends all the dust into the air which mixes with oxygen and becomes highly explosive. Many people have died because of these fires, and there is an ongoing debate over what will be done to prevent another such calamity from happening.

Justin, Good comment on surface area. I think people are very aware of this now! 5 stars. MW

Helium Balloons and Sulfur Hexaflouride: This article was very interesting and I could relate to it which made it easier to read. I have sucked in helium several times in my life, including in chemistry class, if you remember, and have always wondered if there was a gas that sould do the opposite and make your voice lower. This article told me what it was a also a little bit about it. Three things that I knew before I read the article were that helium mande your voice higher (duh), I also knew that in excess it could be harmful because of the lack of oxygen. I also knew that if you suck in helium too much, you could pass out (happened to my dad). Some things that I didn't know were that there actually was a gas that made your voice deeper and also that it was called sulfur hexaflouride. I didn't know that harm could come of any contaminants in the helium or sulfur hexaflouride and make you sick. I never really thought about it not being all helium. The last thing that I didn't know was that instead of deflating over time like a helium balloon, a balloon filled with sulfur hexaflouride will actually increase in size because air flows into the balloon faster than the sulfur hexaflouride can trickle out. It is my belief that Mr. Williams should bring some sulfur hexaflouride into class and let us try it out. :)

Justin, It would be cool but the stuff (SF6) is just so darn expensive!! Good post 5 helios stars! MW

Motion Detectors: This article was a little confusing in some parts, but I think I got the gist of it. There are three different types of motion detectors: one that has a beam pointed at a photo sensor, one that uses radio waves to sense if anything is moving, and one that is heat sensative using infrared radiation. The first one is a simple enough mechanism in which a beam of light (infrared usually) which is pointed at a photo sensor. When this beam is broken, by someone walking past or something, then the light goes on. The second one is slightly more complicated. It sends out radio waves that map where everything is. The waves travel out and then bounce of everything and return to the sensor, like the method of echo location that bats use, except with light instead of sound. When someone/something walks past, the radio waves bounce back differently signifying that there is something there, making the light turn on, or the door to open, etc. The third one is probably the most complicated because it senses body heat from animals of humans. This is the same kind of sight that rattle snakes use. When a warm bodied something comes close to the door, the light turns etc etc. What was confusing to me was the section about the photon-electron connection.

Justin, Interesting post but you didn't tell what you knew and what you learned. 4 stars. MW