Ibarra,+Kelsey

__Helium Ballons__ In this article, it mentioned a buoyant force, which is just enough to lift .0028 pounds for every liter of air an object displaces. Surprisingly, this buoyant force actually causes people to weigh slightly less on the scale, because it's pushing upward. Our true weight would be about .2 pounds more if we were in an area without any air or gas of any kind that could be "pushing" us up. In addition, another important point that was mentioned was how a helium balloon is connected to buoyant forces. Because a helium balloon weighs only about .067 pounds, the buoyant force pushing upward, which is about .2 pounds, makes a negative weight of -0.133. This process is what makes the balloon float in the air. This fact is so interesting to me because i've probably seen thousands of helium balloons, and never realized the real reason that causes these balloons to even float in the first place. Moreover, buoyant forces come from the amount of pressure exerted from gas molecules. Because less pressure is exerted as you go higher up in elevation, there are more forces acting on the bottom of an object than on the top, which ultimately leads to a stronger force pushing upward, known as a buoyant force. I think this point is the most important because it explains many little things that go on in life, such as the process of helium balloons floating.

Kelsey, I agree that buoyant force does seem to be small yet important! Good job! 5 stars. MW

__Sugar, an unusual explosive__ In 2008, the walls of the Imperial Sugar Company were blown. A huge explosion occurred, killing 13 people and injuring 40. But what was found the most bizarre, is that the main cause of this explosion was a simple substance that people consume everyday in society: sugar. I never knew that sugar had such capabilities as to start such a big fire. I've always heard about explosions because of a shortage in a electrical unit, or because of a bomb, but never because of sugar. One other chemical reaction that I was interested by was the browning of apples. I eat apples every day, and so of course I've witnessed how the apple's surface turned brown after being cut for a period of time. However, it never realized that this simple change was considered a chemical reaction, resulting from the oxygen interacting with the surface molecules of the apple's skin. To add on, I was shocked that the U.S. Chemical Safety and Hazard Investigation Board reported in 2006 that dust explosions are being taken as a serious hazard. That is frightening because there is dust that accumulates on everything that we come in contact with in society, and it actually can be very dangerous. Furthermore, in class, we talked about combustion as being a common chemical reaction. We also even burned sugar with the burner and saw how it reacted in a lab, so it was easy to understand when they talked about the reactants and products formed by the explosion at the Imperial Sugar Company.

Kelsey, Well done! I like the fact you mentioned the apple connection! 5 stars! MW

__Where do Chemical Elements Come From?__ Chemical elements come from supernova explosions, where chemicals combine, forming ions and molecules. However, hydrogen is an exception; it comes from the Big Bang explosion.

Kelsey, Good job! 5 stars. MW

__Motion Detectors__ I always understood the general idea of motion detectors, which is that it senses a form of energy. I also knew that some motion detectors worked off of light beams, like my garage door. The second technique of sensors monitoring the reflection pattern was also familiar to me because I have used several items with this such as automatic doors that are in practically every store. However, the one technique of motion detectors that I was never aware of, was the monitoring of infrared radiation. I didn't realize that one human being could give off enough infrared radiation, from being warm-blooded, that would signal to a motion detector of one's prescense. Furthermore, it was interesting to read that although a human's body temperature is 37.0 degrees Celcius, their actual skin temperature is only 33.9 degrees Celcius. I never noticed any temperature change! Moreover, the articles described rattlesnakes as being able to detect infrared light, which is beneficial when seeking prey that can not see them. It's so fascinating that a creature so small can have capabilities, such as what was just mentioned, that many other creatures don't have.

Kelsey, Looks good! 37 degrees is your core temperature. Your skin is cooler since it's exposed to lower temperatures - at least you hope! 5 stars. MW

__Crude Oil__ I never realized how much crude oil was used in many everyday things. I always knew that gasoline to fuel your car was made from crude oil, but i never realized things such as asphalt on the ground also originated form this crude oil. In addition, I found it extremely interesting the complex process that is used, especially by the industrial business, to separate parts of the crude oil for its purposes through distillation. Furthermore, the movie explained that the oil enters the tube at 330 degrees Celsius, and then some parts of the oil can cool off to as low as around 80 degrees Celsius. I think it's so shocking how dramatically these oils can change temperatures just based off of their boiling points, which can ultimately determine the oil's purpose for materials used in society. I thought that fact to be one of the most interesting parts of the video.

Kelsey, You are a talented writer! A very good summary that picks out some very important points. 5 big stars! MW __Mentos and Coke__ The Mentos and Coke article definitely interested me because I have seen this reaction many times on several TV shows, and I was always puzzled by what caused this "explosion" of Coke to happen once Mentos was added. The article made it sounds like although most people believe the reaction has to do with the ingredients, in all reality, it has to do with the rough surface of the Mentos, which causes the molecular motion to increase. First off, it appears as though there's more that meets the eye because I always assumed Mentos were a tiny, smooth piece of candy. Secondly, I was surprised that something as simple as a rough surface of an object, can cause something as huge as the reaction the Diet Coke has when coming in contact with the Mentos.

Kelsey, Good post! I think I should get some Mentos and look at them under a microscope! 5 stars. MW

__Redefining the Kilogram__ First off, I was interested in learning that there is an International System of Units that is used to define measurements that I use everyday. I always took for granted that these units, such as the kilogram, were just that way! Also, I was shocked to read that the kilogram is the last of the SI base units to still be based off of a physical artifact. I would have thought that scientist would not want to use a physical artifact because these sorts of things can change based off of a manufacturer. Last but not least, I was surprised that the international prototype for the kilogram has lost size overtime. I believe this is the MVP because it is important that the kilogram measurement is accurate since it is used by so many people in our everyday lives.

Kelsey, Nice summary! you have a pleasant writing style. 5 stars! MW