Wednesday, April 21, 2010

Earth Day #2: Energy & Oil

Ok, so we mentioned that energy concerns, especially peak oil, are very important topics right now.  A fellow blogger, John L. Clark, has written an interesting piece that explains some of the interdependence of oil, population and consumption, and also has some ideas about what the average citizen can do to address these concerns.   

There's also a book that I'd like to recommend that gives a very good overview about sustainable energy.  It's called Sustainable Energy Without the Hot Air, by David MacKay.  I really like this, because it's got a lot of good information.  I'd recommend starting with the 10 page (pdf download) summary  and then go on to the main book, found here.

Don't be thrown off by the website. It's useful, because it helps the online reader navigate sections of the book, which doesn't have to be read sequentially. I'd recommend starting at Chapter 23, "Sustainable Fossil Fuels" because it talks about coal, which is the next consideration after oil.  Also, a Gt is a gigaton (2 billion pounds, or the curb weight of about 400,000 Hummers.)

Windmill, courtesy of Storm Crypt

Monday, April 19, 2010

Earth Day!

April 22, 2010 is Earth Day, and in honor of that, we're going to have some posts about the environment.  This is more of the application and effects of science rather than the research, so hopefully it will be a fun series. 

First, there's the history of Earth Day.  This was started about 40 years ago by Gaylord Nelson, a Senator from Wisconsin who wanted to call attention to environmental issues.  He believed that grass-roots activities like the ones used by Vietnam protesters provided excellent models that he could use. So in the fall of 1969 he announced that there would be a grass-roots demonstration in the upcoming spring.  During the winter, people called, wrote and sent telegrams about their concerns.  (Yes, the telegram, and no snickering. The world wide web was just California and Utah in '69, and email wasn't going to show up for another 2 years.)  It was a big success: the first Earth Day was on April 22, 1970, and was celebrated by about 20 million people in the US.

How do we use the Earth?

Monday, April 12, 2010

Citizen Scientists

There's an article in Nature magazine that talks about the problems with thinking of science education as only a classroom-based activity.  The big issue is that funding and policy initiatives tend to be limited to grade-level specific education.  This is important, but with the rise of the internet, there's a lot of good-quality, easily accessible content, which results in more people being self-taught about science, rather than from formal classroom study.

There are mixed feelings about this. On one hand, self-directed learning eliminates the big complaint about the classroom: in school you can't always learn what interests you, or learn things at the same time you'll need to use them.  So a Google search on how to build skateboard parks tends to be more interesting to people than sitting through an introductory Physics course, even though both involve the classic problems of inclined planes and sliding blocks.  Also, by using informal tools of education, people can learn about a topic at the time they need it, not just during a brief slice of their academic year.

However, one concern is that there's less attention to strengthening the informal learning communities.  While every child is (supposed to be) guaranteed a public education in the classroom, places that reinforce this learning, like museums, libraries, parks and activity centers are losing funding.  This may mean that self-directed learners only find their communities online, instead of with their neighbors.

Also, while there is a lot of content available to people, there are still questions about what is "good" content?  Who is a valid authority?  What makes a reliable study?  How is this information relevant or useful?  An example of this misunderstanding was when the advocacy of high-profile celebrities implicating the MMR vaccine to the rise in autism was influential in fostering negative public opinion towards vaccines in general.  So in spite of the dissent among researchers, and the fact that the original MMR-autism study was discredited, the rates of MMR vaccinations dropped in the past decade, leading to spikes in measles outbreaks and serious policy concerns

The Nature article has an even bigger question for informal learning: "how do people integrate the disparate pieces of knowledge they acquired at different times and places? And how can anyone assess the overall outcome?"  Their suggestions are to create more partnerships between regular people and community resources, or to pair schools with existing science and research centers. 

I think these are great ideas, and I'd also like to see policy initiatives that are actually geared to teach the non-student how to screen and use the huge amount of scientific literature that's so easily available.  We already do this with our diets by using the Food Pyramid, and it works very well. I think a great idea would be an easily-understood, highly-broadcast diagram that would show people the basics of science literacy:  how to read a chart, how to distinguish between sources, what's the math behind scientific studies, or how to read a journal.  What about you?  Where do you learn about science, and how would you improve it if you could?

Photo Credits:  Law_Keven, Flickr.

Friday, April 9, 2010

The Genome - Going from Letters to Words, Part 1

Let's start with a quick review of our earlier discussions on DNA/RNA.   We said that DNA is our master blueprint, and RNA is like a copy of those instructions that goes to the builders.  We briefly distinguished DNA from RNA by how their sugars are different:  DNA uses deoxyribose and RNA uses ribose. We also said that nucleotides are used to make both molecules, and we discussed how in both cases, the nucleotides are arranged in linear strands, like beads on a string.  We compared the DNA structure to a set of line dancers: one line holding hands with the left and right dancers, and standing opposite their partners.  In DNA there are connections between the two strands, which cause the winding and characteristic double helix form.

This is a picture like the last one we saw.  We can see that the A (adenine) always pairs to T (thymine) and the G (guanine) to C (cytosine).  It's like our line dancers are forced to always choose certain partners to dance with.  In DNA, this forced interaction is because of the bonding between facing pairs: these are the light dashes between the nucleotides.  These are hydrogen bonds between the electronegative (electron withdrawing) nitrogens and oxygens, and the hydrogens on their faced partners.  This is a much weaker kind of bonding than what happens between the side-by-side neighbors (about 1/10th the strength) but these bonds are strong enough to stabilize the structure.  Anytime a structure, how it's bent/shaped or it's position to another object is stabilized, it costs energy to have it not be that way. It's like taking the pacifier away from the baby -- there's a price to pay.  In general, Nature spends energy reluctantly: lower energy means something is more likely to occur. 

So now we have our dancers in two lines facing each other, like a bunch of middle-schoolers in 6th period gym.  For the sake of this example, the kids are named after each nucleotide (so we've got a room of kids, but just 4 names among them.)  Their teacher, Mr. Chargaff, puts them in Group 1 and Group 2, and tells each group to stand in line.  Then he tells them they have to pick partners from the opposite group, and the same partners each time.   What does he tell the substitute teacher to worry about?  What can she gloss over?

The Influence of Primary Structure
Chargraff's rules tell us that all we need to worry about is lining up one line of kids. Once we have that figured out, the position of the other children is automatically enforced.   So if the Group 1 kids are lined up as:

A, T, C, C, G, A; then their partners will line themselves up as
T, A, G, G, C, T, and vice versa.

If the Group 1 kids line up as C, T, C, C, A, A;
then their partners line up as  G, A, G, G, T,  T.

So we only need to get one group of kids organized, and the other kids do the work for us.  The genetic code works in a similar fashion: once we know the line up of one strand, the second strand is precisely defined.  RNA exploits this effect -- it's generally single stranded, which is all that's needed to make an accurate copy of the DNA master print.

So we have a line up of nucleotides.  Where does that get us?

How Robots are like Hamburgers