McNamara,+Lauren

__Motion Detectors__
I never really thought about how motion detectors worked before. I always thought it was just like a video camera that saw motion, but it is not. There are different kinds of motion detectors. i also always thought that the ones at the grocery store were like weight sensors because they have those little things on the ground in front of the door and when you step on them the door opens. The motion detector that I like the best is the light one because it actually makes sense to me. Like in all the movies where they have those lasers that if you touch them they burn you. I think it is kind of like that except the door opens and you don't die. 12/15/09

Lauren, Thanks for the laugh! I think some doors do have weight sensors. Anyway good job! MW

====I think that it is really interesting that you you can suffocate yourself by breathing in helium of sulfur hexaflouride. I think it is interesting that when you hold you breath you gasp for breath because of the build up of CO2 not because of the lack of oxygen in your blood. But I think that you would have to be really stupid to accidentally kill yourself that way - although you wouldn't really die because once you pass out you would start to breath again, and you would not die, unless you hit your head or something on the way down. I also think it is interesting that sulfur hexaflouride is inert (which means non reactive) when it is made of two highly reactive things, one of them being gunpowder. -12/4/09====

Lauren, sulfur is found in gunpowder but is not actually gunpowder! MW

__Dust Explosion and Stoichiometry__
====There was a fire because the sugar dust caught fire and made like a chain reaction. I found this very interesting because even if there is a little spark and the tiniest little smidgen of sugar dust (which is so small an amount you probably won't even notice it) then that dust will catch fire and because it is so light it burns quickly and then more smidProxProxy-Connection: keep-alive Cache-Control: max-age=0 Connection: keep-alive Cache-Control: max-age=0 ns of dust catch fire and there is a chain reaction. I wonder if like regular dust that like collects on furniture is explosive to. I think this is related to stoichiometry because of combustion and it's like a chemical reaction and oxygen is in excess. -11/3/09==== Lauren, Good post! I have never heard of a house exploding from dust. MW

__Mole Day!__
==== I learned a lot about Mole Day. I learned that there is a mole pledge and if there is no mole available (which there usually is not) then you're supposed to face the earth. I also learned that there is a Mole Day theme song about the Molar express. I learned that the mole is Avogadro's number. That it is 6.02 x 10^23. I learned that for a given molecule, one mole is a mass (in grams) whose number is equal to the atomic mass of the molecule. - 10/7/09  __Airline Security__==== ====Why would someone bring a bomb onto a plane? I know that people are evil and stuff, but that is just really, really stupid. They must know that they're going to get caught. The article says that they usually find 20 firearms a week. That's ridiculous. Don't the people know that if they bring a gun onto a plane they are going to get caught? And that if they get caught they are going to go to jail? They're just being stupid. If you're going to travel with a bomb, take a car.====

__Redefining the Kilogram__
====I found it interesting that the kilogram is the only measurment still defined by a physical artifact. None of the other sI units are. I wonder how they decided to leave the kilogram a physical artifact and why they decided to use platinum to make it. In 2005 they suggested we convert it like all the other ones because over time the kilogram has become less exact. I think that they should do this so that it can become exact like all the other measurements. I am confused as why they did not choose to do this. - 9/8/09====

__Why is Measurement Important to Me__
====If I was cooking and I messed up the measurement I would be very upset. I would be very upset because, I went through all the work to cook the food and then it didn’t turn out good I would be upset. For example if I were making cookies and used tablespoons of salt instead of teaspoons then the cookies would be do too salty and they wouldn’t taste very good. Another example would be if I were baking a cake and accidentally messed up the amount of sugar then it would either be too sweet or not sweet enough. - 8/31/09====

__Separation of Matter__
====I didn’t know that crude oil was a mixture or that it had hydrocarbons in it. I found it interesting that as a mixture crude oil is useless but then they use distillation to separate the hydrocarbons. Distillation is related to chemistry. I also found it interesting that they have to immerse the tube in hot water and not heat it with a flame at first because it would catch fire. But after they collect the first fraction it’s safe to heat with a flame. It's cool how they do this on a “mammoth scale”. - 8/28/09====

__Classifications of Matter__
====The first chart shows pictures of the differences between a heterogeneous mixture, a solution, an element, and a compound. It also shows how you can determine if they are a heterogeneous mixture, a solution, element, or a compound. I like this chart the best because it has pictures to help you understand better. I like the second chart because it shows you how to break them down into categories. For example you put them into the categories of mixtures or pure substances, and then you break it down further into homogeneous, heterogeneous, compounds, or elements. The third chart shows roughly the same thing.Proxy-Connection: keep-alive Cache-Control: max-age=0 0I like the fact that====