Posted in Art, Science at 2:12 am by Administrator
Several years ago, on a hot humid summer day in Portland OR, me and a friend were at a grocery store, and the dry ice freezer caught my eye. Kind of an impulse buy, I have to admit, I asked the cashier for a pound. They wrapped it up in paper and sent me on my way. Once we got home we unwrapped it, and for a while we were not quite sure what we were going to do with it. As the dry ice sublimated I noticed that it would sink, and kind of hover along the table top. This got me wondering.
Sometimes it’s easy to forget how humiliatingly invalid our theories can prove to be, even if they do seem to explain what we observe with a certain amount of reliability. Not more than 300 years ago, the common consensus to explain combustion went something like this. Everything that is capable of burning, can do so because it has been endowed with a certain amount of an invisible, massless, colorless, odorless substance called Phlogiston. As the substance burns it releases it’s phlogiston into the air. Once that happens, the air becomes saturated with this phlogiston, and can hold no more, then there is sort of an equilibrium of phlogiston between the burning object and the air, then the object stops burning.
In my last quarter of the General Chemistry sequence we started examining something called beta-decay. It presented the possibility of essentially changing one atom into another, say start with silicon and end up with phosphorus.
This has to do with the interplay of what makes up all atoms, like everyone learned in high school, we have protons(+) and neutrons(0) in the nucleus, and a bunch of electrons(-) swarming around them. The number of protons in an atom determines the identity of the atom and are balanced by the number of electrons swarming around the atom. The neutron has no charge, so this does very little in the atom other than determine how heavy it is.
You can add and subtract neutrons from the nucleus without changing the identity of the atom. When you do this you get what are called isotopes. Each atom has a stable number of these neutrons, and when you find isotopes that are not stable, they stabilize by undergoing beta decay.
Nitrogen gas (N2) makes up about 80 percent of the chemical cocktail we call air. Its colorless, odorless, relatively unreactive, and emotionally distant. But it’s these very properties that make nitrogen itself so useful.
This will keep you awake at night. This guy in the 30s discovered that numbers that are taken from real things; heights of buildings in New York, number of people on the city bus, number of minutes it takes to get to work, the number house you have in a street address, all these numbers will most likely start with the number 1. The next most likely number that they will start with is 2. The next? That’s right 3. And the least likely number to start these seemingly random sequences from nature is the number 9. Read the rest of this entry »
So the other day my teacher was riffing about an idea she had for the perfect murder. She called it death by isotope effect, and it involved freezing deuterium oxide, and placing it in an alcoholic beverage. Now deuterium oxide, also known as heavy water, is simply H20 but instead of hydrogen nucleus containing only one proton, it contains a neutron as well, giving it double the weight without effecting the charge. Since the oxygen molecule is far heavier than both the hydrogens this ends up being only a 1/9th increase in weight over regular water but does lead to it’s name.
Her idea was that, although the heavy water ice cubes would sink in regular water, they would float in alcohol, so you would be able to slip them inconspicuously into someones drink and down goes the heavy water with all the booze. The heavy water would never show up in a toxicology report, and the crime would remain unsolved. (48 percent of murders each year in the US remain unsolved anyways, so this seems like being over cautious)
So what makes heavy water toxic? Well the added mass in the nucleus of the hydrogens makes for a slightly shorter, slightly stronger bond than the normal H20. Since biological processes depend heavily on this bond strength being the same as it has been for the last say 2 billion years, it makes cell divisions necessary in the building of certain proteins rather difficult. This eventually leads to tissue breakdown and death.
So why does the MSDS rate deutrium oxide as nonhazardous? Well the amount of deutrium oxide needed to actually make this biological change happen is quite large. Some estimates say that the isotope would need to make up half the water in the body. Being that we are about 60 percent water, I will need to ingest about 42 pounds of this stuff. Being that the going price of heavy water is about a dollar per gram, this puts the price of my execution at around 20 thousand dollars. And for the average person this would be quite an investment and I must say a little suspicious, perhaps even more suspicious than the old bloody knife in the dumpster, or better yet the melting murder weapon from that episode of Matlock, the knifecicle.
Several years ago, on a hot humid summer day in Portland OR, me and a friend were at a grocery store, and the dry ice freezer caught my eye. Kind of an impulse buy, I have to admit, I asked the cashier for a pound. They wrapped it up in paper and sent me on my way. Once we got home we unwrapped it, and for a while we were not quite sure what we were going to do with it. As the dry ice sublimated I noticed that it would sink, and kind of hover along the table top. This got me wondering.
In my last quarter of the General Chemistry sequence we started examining something called beta-decay. It presented the possibility of essentially changing one atom into another, say start with silicon and end up with phosphorus.
