Evolved To Wonder

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Teach Me Chemistry - Lesson 4

We saw at the end of the last lesson that protons and neutrons each weigh approximately one atomic mass unit (amu, unit “u”), while electrons in comparison weigh only 1/2000th of that.  Formally, an amu is defined as the exactly 1/12 the mass of carbon-12.  Let’s look at how atomic number, mass number, and the numbers of the subatomic particles  are related.  

X represents the element’s chemical symbol found in the periodic table, while A is the atomic mass and Z is the atomic number (also sometimes known as the proton number). For instance, represents the element carbon - “C” in the periodic table - which has 6 protons and a mass of 12 amu.

Because we know that protons and neutrons are the only subatomic particles that count towards the atomic mass and each has a mass of one amu, we can calculate that the number of neutrons in this atom is 6.

A - Z = # neutrons
12 - 6 = 6

It’s “Wannabe” for the record

I am not generally one of those people who gets flashes of inspiration in the middle of the night or in their dreams or things like that.  Even when I’m obsessive about an idea for an experiment or a writing project I’m just not the notebook on the nightstand type.  However, this morning I woke up about an hour before my alarm rang.  Usually this would be because Callie is standing on my face yammering, but today the only thought in my head was how I forgot to include a necessary transgene in one of my upcoming crosses.  I have no idea what prompted that, although I’m grateful to my subconscious for bringing it to my attention.  Why could it not have done so a week ago so I didn’t waste all this time?  . . . I don’t know.  I do know that I went back to sleep for an hour and then woke up with a Spice Girls song in my head, which has remained there all day.  Which just proves that in my case flashes of intellect in the early morning are an exception to the rule.

One of my undergraduates is giving his first lab meeting on Thursday.  I am way more nervous than he is.  It stems from not feeling comfortable with the analysis myself; I have so little background in behavior.   In fact that’s part of the reason I asked our PI for a lab meeting in the first place, to discuss the issues I feel that we’re having in getting the most meaning out of the data.  But PI is excited to see the results, and thus undergraduate and I are going to have a pre-meeting meeting at my insistence to make sure that at least his presentation is organized and clear even if everything in it is meaningless.

On Saturday a colleague from whom I needed technical advice came to my lab with his three year old daughter.  She used my highlighters to color on all of the paper in the recycle pile and then decorated them with all the colored lab tape.  I guess I should just be thankful she didn’t decide it would be fun to pull out all the cotton balls to set free the little bugs.

Teach Me Chemistry - Lesson 3

Right about now in any intro chemistry course, you could you could be forgiven if you thought you dozed off and sleepwalked into the history class next door.  Most books choose to introduce the fundamental subatomic particles by putting them in the context of their discoveries.

I.  Early Chemistry

For example, In 1774, Antoine Lavoisier proposed the following:

It is always true that the total mass of substances formed by a chemical reaction is the same as the total mass as the reactants before the reaction happened.  In other words, matter can neither be created nor destroyed in a chemical reaction.  This is the Law of Conservation of Matter. It means that in any chemical reaction, if you can find a way to measure exactly how much of every reactant you start with, and exactly how much of every product you end up with, you would find the masses of each group added all together would be the same.

If AB + DC –>  AC + BD, then Mass (AB + DC) = Mass (AC + BD)

In approximately 1805 Joseph Proust described an initial version of what we now know as the Law of Definite Proportions:  All samples of a compound have the same composition - that is, they have the same proportion of elements by mass.

For example, let’s think of one everybody knows, H₂O.  Every water molecule has a ratio of 2 hydrogens to one oxygen.  If we were to, say, add an extra oxygen to the molecule to make it H₂O₂, we would now have hydrogen peroxide - which you can use to bleach your hair or clean out your earwax, but you wouldn’t want to drink or swim in.  Hereby we see that if we change the ratio of atoms in the compound, we change the identity of the compound.  Sometimes dramatically.

This may be predictable, but…

I’m gonna give a thumbs down to Bobby Jindal.  Last night he said:

“[The economic stimulus package] includes $300 million to buy new cars for the government, $8 billion for high-speed rail projects, such as a ‘magnetic levitation’ line from Las Vegas to Disneyland, and $140 million for something called ‘volcano monitoring.’ Instead of monitoring volcanoes, what Congress should be monitoring is the eruption of spending in Washington, D.C.”

Thank you Governor Jindal for reminding me how obnoxious anti-science sentiment can be.  You know, I do understand that it might on the surface seem like those aren’t the first projects we should pick to stimulate the economy, but I feel like he hasn’t thought about it for more than 4 seconds or so.  I mean, aren’t high speed rail lines a GOOD thing?  They’re energy efficient, aren’t they?  Better than flying or driving?  And people need to be employed to build them?

“Something called volcano monitoring”?  Is it. . like. . . hard to understand what that means? And wouldn’t we. . . like to know. . . if a volcano is about to erupt?