Nizinski,+Allison

I learned a lot about motion detectors from reading this article. I knew that a photo sensor senses light and that it how the photo sensor detects motion. Secondly, I knew that different materials have different thresholds, and so sensors can be made for just about any type of light. Thirdly, I knew that bats use echolocation to locate insects for a food source. I did not know that light is considered as electromagnetic radiation in the ultraviolet, visible, and infrared range. Secondly, I did not know that a high-intensity, low-frequency beam of light (ex. strong red light) would cause no electrons to be ejected from a given surface, and yet a low-intensity, high frequency beam (weak blue light) could send electrons flying. This article was very interesting. I understood the concept that ping pong balls could not shatter glass but a steel ball could shatter glass. I also didn't know that there are so many different types of motion detectors such as detectors that sense light, temperature, or using echos to sense objects and motion. I am glad that we read this article in chemistry because I would have never even thought about these interesting concepts.
 * Motion Detectors**

Well done historian! Well done! 5 stars. MW I knew that helium balloons rise because there mass is lighter than air (the balloons are less dense than air.) Secondly, I understood the concept that when dealing with an object, “there must be some greater acting in the opposite direction to make it accelerate upward. I knew this because gravity exerts its force. I knew this because gravity exerts its force on every object on earth. Thirdly, I also was aware of the buoyancy concept. Object float or are buoyant because the force acting on the object (normally gravity) is the exact weight of the air or water that is being displaced by the object. I did not know that when air is taken away, buoyant force is taken away as well. I did not know that the atmospheric pressure of Mount Everest is about 70% lower than it is at sea level. Thirdly, I was not aware that grams and kilograms are not units of force. I learned from the article that pounds are a unit of force. I knew that helium makes one’s voice higher and I remembered that Mr. Williams said that there was a gas that lowers one’s voice. Secondly, I knew that a balloon filled with helium gas tends to deflate more quickly than a balloon filled with air. Thirdly, I was aware that some people often tend to overdo helium breathing and it causes them to pass out. I did not know the name of the gas that lowers the voice after it is inhaled. I learned that this gas is called sulfur hexafluoride. Secondly, I did not know that breathing in helium causes suffocation. This is explains the lightheadedness that I myself have experienced after inhaling helium gas, I just never knew the scientific reason. Thirdly, I did not know that breathing in helium and/or sulfur hexafluoride could be toxic due to impurities in the tanks. The source of the tanks should always be taken into consideration before one breathes in helium or sulfur hexafluoride.
 * Helium Balloon Article**
 * Sulfur Hexafluoride**

Allie, Great job once again! You are eminently qualified for that historian position. I hope you get it! 5 helios! MW
 * Dust Explosion**

In the article “Plant Blast Rekindle Dust Debate,” a dust explosion occurred at a sugar plant. Apparently, the dust was combustible, which is why the dust explosion occurred. I was not previously aware of how dangerous dust explosions are or how they occur. All it takes is one tiny spark and an entire factory with tiny particles can become enflamed. This situation never crossed my mind in my entire life and I could not believe that many people died or became injured because of the dust explosion. I am beginning to understand the quote from Crowl that “a lot of solid material, when finely divided into a dust form, becomes highly explosive.” After reading that smaller particles have larger surface areas, this concept began to make sense because “less energy is needed to set the particle on fire, and it will burn faster.” I learned that as long as there are oxides (usually the oxygen (air) in the atmosphere), small particles, and a spark or something that could ignite the small particles, a dust explosion could occur. I never considered sugar as an explosive. I did some outside research and it appears that coal dust explosions often occur in mines, but sugar is not commonly associated with dust explosions. This article was extremely informative and fascinating. This article taught me a lot and it reminds me how much chemistry is used in daily life.

Wow! Allie this is great! You really got a lot out of this article and I love your writing style! 5 super stars!!! MW Mole Day

I read the article on Amadeo Avogadro, who is one of the founders of chemistry. According to the website, Avogadro’s law “simply states that at a fixed temperature and pressure, equal volumes of gases contain the same number of molecules.” I did not realize that Avogadro’s Law was not published until his death. Avogadro’s number is (rounded off) about 6.02 * 10^23. I am now starting to realize that many of the famous scientists based their hypotheses off of other scientists’ experimentation. In this case, Amadeo Avogadro relied on the lab work of Joseph Gay-Lussac and Avogadro never proved his hypothesis in his lifetime because he never did any completely accurate experiments. I found this article extremely fascinating. Avogadro was such a huge contributor to the science of chemistry. I learned a lot by reading the article about Amadeo Avogadro, from both a historic and a scientific standpoint. Although the concept of Avogadro’s law was unpopular and/or unaccepted by the majority of people, Avogadro has made such a huge impact on modern chemistry. His hypothesis and some of his work is still used today.

Allie, Once again you show your command of the written word! 5 moletastic stars!

Where Do Elements Come From? I learned after reading the article “Where Do Elements Come From?” that elements come from the stars. The article said that, “Inside the star were most of the first twenty-six elements.” The article also said that after the explosion of stars, other elements formed. When stars explode, nuclear fission and/or nucleosynthesis can occur which form certain elements. The elements that are present in our every day lives are from stars/star explosions. I learned that some of the elements from the stars/star explosions under special conditions descend to Earth where humans come in contact with many of the elements daily. When the stars explode, their collapse (referred to as a supernova) causes newly formed elements to form other elements. According to the article, stars are originally made up of hydrogen. The element hydrogen in a young star is the base for “all known elements.” I also learned about “beta decay” which takes place before a star explodes. I learned that a neutron can become a proton and a neutron. Beta decay causes a nucleus to become the nucleus of “the next element of the periodic table.” But, the “r” process which takes places during explosion “allows for the rapid capture of neutrons.” After reading this article, I feel like I have gained a lot of knowledge. I never knew, nor even thought about where the elements come from or originate. I am glad that I learned this fascinating piece of information because it helps me understand how important chemistry, the elements, and the periodic table are to every day life.

Allie, You are off to a fantastic start! Good writing! As I read your remaining post I continue to be awed by your grasp of these rather mysterious concepts! 5 supernova stars for you!!! MW

I was surprised to learn that one in every eight Americans has a tattoo. I was also surprised to learn that tattoo ink has not been chemically altered over the years. Thirdly, I learned that tattoo ink is long-lasting because the ink’s pigment is injected into the layer of skin called the dermis. To make certain colors of ink, different chemicals are used. For example, the color blue is sometimes composed of copper salts or cobalt oxides. For the color white, the chemicals: titanium dioxide, zinc oxide, or lead carbonate are sometimes used. A company by the name of Freedom-2 claims to have invented a removable tattoo ink. Supposedly, after one laser treatment, the pigment of the tattoo ink is reabsorbed into the body of the tattoo wearer. Other tattoo inks can take months to fade if accompanied by many laser treatments. So far, Freedom-2 has only come out with three removable inks. The colors are black, white, and gray. Freedom-2 plans to come out with a more extensive color palette in the future. This could revolutionize the tattoo industry and cause all tattoos to become removable.
 * Tattoo Ink**

Allison, Good job! 5 big stars! MW

After watching the You Tube video about crude oil, I learned that crude oil is useless as a mixture. To make crude oil useful, scientists use the process of distillation. To distill the crude oil, the crude oil is dropped into the bottom of a test tube and the test tube is gently heated by a hot water bath. At about 40 degrees Celsius, the crude oil condenses in the condenser. I found this very fascinating because I never knew about the distillation process. Secondly, I learned that crude oil is used in many items that I use in my daily life. Thirdly, I learned that the lower a molecule, the higher the boiling point. Logically that makes sense, but I guess that I never thought about the relations to chemistry that molecules boiling in water have before.
 * Crude Oil**

Allison, Good thoughts. Well written. 5 stars. MW

The kilogram is a SI Unit used to measure the mass of an object. It is facinating that their is an American standard kilogram that is used to base American measurements off of. But, I thought that it is distubing that the weight of the American standard kilogram can "drift" or change. If it is the standard unit for measuring all of the other kilograms against, the measurements could be inaccurate. According to the article, "the kilogram is the last of the SI base units that is still defined by a physical artifact." Some chemists hope to redefine the kilogram based on Avogadro's number (constant). Most materials that would be considered for the international kilogram could potentially change slightly. Apparently, redefining the kilogram would help chemistry students to better understand the mole concept and Avogadro's number. If redefining the kilogram will cause concepts to be easier to understand, I will support redefining the kilogram.
 * Redefining the Kilogram**

Allison, Good comment on Avogadro's number and the mole. These are tough concepts. 5 stars. MW