Fryeburg Academy Physics

Here’s another post of The Boston Globe’s feature The Big Picture, this time a series of photos of a recent eruption of the volcano Mount Redoubt in Alaska. #1 is now my desktop background. There are some great photos in here, I recommend you check them out.

Yes, it matters. I shared this with some classes, and I’m posting the entire recording here so that you may listen to the whole maddening conversation. I’m glad to hear that all of you recognized that changing the word behind a number can change the number a great deal, and I hope you maintain that level of common knowledge and sense in your travels through the world. 

The episode inspired a blog to keep track of everything that was happening, and you can read all the details here.

This is one of the more inventive methods I’ve seen for cheating on tests. I have to wonder if all the time that it would take to really pull it off might be better spent actually studying for the test? Take the lazy way out: it’s easier to study than it is to work up something this elaborate.

And by the way, I know this trick. If you’re dumb enough to try this on one of my tests, you deserve the zero you’ll get!

No, I’m not asking for donations for my quest to fly in zero gravity, I’m telling you how you can help professional astronomers catalog the night sky. Here’s the back story.

Almost all telescopes used these days for serious research are controlled by a computer. Everyone has a mental picture of astronomers with their eye to the lens of a big scope, but in reality they spend most of the telescope time sitting at a computer desk and monitoring the data. A digital camera system allows dozens or even hundreds of images to be captured during a period of observation and available within seconds. No waiting for that pesky film to develop as in days past. This is good and bad: it’s good because there’s a lot of new information out there, but it’s bad because it takes a long time for astronomers to sort through it all.

Enter the Galaxy Zoo project. The Sloan Digital Sky Survey produced images of roughly a million galaxies, which then needed to classified as spiral or elliptical, along with some other basic information. It’s not very difficualt and might only take 30 seconds to classify one galaxy, but the small team of astronomers estimated it would take them two years to get through everything. The Galaxy Zoo went online to enlist the help of average people with an interest in astronomy in classifying galaxies. In the first year, 150,000 different people made over 50 million classifications.

Registration is free, the training session takes about 5 minutes, and then you’re on you way to classifying galaxies. Do as many or as few as you like, for as long or short a time as you want; every little bit helps.

Here’s another chance for some extra credit for the fifth marking period. I have been maintaining a blog (which you obviously know if you are reading this), and it would be accurate to say that I’m disappointed by the general lack of participation, especially over the last two or three months. Granted the posts haven’t been as frequent as they should be, but there are plenty of good chances to comment on stuff already here.

One of the reasons I think I don’t get much traffic is that most students aren’t aware of the awesomeness that is RSS. Your task for this assignment is to figure out what RSS is, how to use a reader (there are a bunch of good free ones out there; Google Reader is my preference), and demonstrate how to use one with a screencast.

So what is a screencast? It’s a movie capture of what’s happening on your desktop. How do you make one? Well, that’s something else you’ll have to figure out (here’s a good place to start). You’ll need some software (free downloads are available) and an external microphone to record your voice.

So that’s your assignment: make a screencast with audio instructions on how to configure an RSS reader. Here are some questions that your screencast should answer.

1. What is RSS?
2. What kind of sites use RSS?
3. How can you tell if a website has an RSS feed?
4. What does the RSS feed itself look like?
5. What is an RSS reader?
6. How do you subscribe to an RSS feed using a reader?
7. What are some good sites (besides this one, of course) that you’ve found to put in your reader?

There is not a minimum length for your screencast, but it shouldn’t be much more than 5 minutes in length. Save your screencast as a video and upload it to YouTube, then email the link. In order to get credit I must receive the email by the end of the fifth marking period: 2:32 pm on Friday May 1. Any email received after this time will not be accepted, and any video that is not emailed to me will not be accepted. Videos that meet the requirements satisfactorily will be counted as two standard homework assignments (30 HW points total for Honors, 50 for AP). Please leave your videos on YouTube so we can all enjoy them!

Addition 3/29/09: here is a pdf file that gives an overview of screencasting. Might be useful!

Here’s an interesting diversion. Discussion of the future and the big scary question “What do I want to be when I grow up?” is something that is probably on your mind, or at least has crossed your mind in recent months. I expect that most of you will wrestle with thoughts on this subject in the near future, and you don’t need to answer it right away. Personally, I still haven’t decided what I want to be when I grow up*, and I know many people my age (and older) who fall into that category as well.

I recommend you take this personality test if you have a few minutes. It’s based on the Myers-Briggs Type Indicator; while this little test is not the full-blown official thing, it might give you some ideas about career fields that fit your personality. The results will be in the form of a four-letter code, which you can then use to see some recommended careers. Be sure to read the Wikipedia article about your type as well, and if you feel like sharing feel free to post a comment and tell us what your type is.

For the record, I’m ISTJ.

*Unfortunately, not growing up is not really an option. We all have to do it, no matter how much we really are Toys ‘R’ Us kids.

Ever had to write an equation on the computer? Microsoft Word has a built-in equation editor, but it’s not on the standard installation package, which means you need to install it from the disk to use it. Apple Pages is far superior to Word in most respects, but it doesn’t have the equation editor. If you’re making a website and need to incorporate an equation, how exactly do you do it?

I found this online editor which allows you to write the code for the equation in LaTex (a), and the website renders it as an image. The coding looks pretty nasty but it’s actually pretty straightforward, and with the editor buttons on the app you can probably figure it out. I’ve done the two equations for a perfectly elastic collision (with vbi = 0) as an example.

LaTex code: v_{af}=\frac{(m_a-m_b)}{(m_a+m_b)}v_{ai}
Generated graphic:

LaTex code: v_{af}=\frac{2m_a}{(m_a+m_b)}v_{ai}
Generated graphic:

If you are not aware of a huge amount of discussion in the last few years about climate change, fossil fuel alternatives, and renewable energy, I respectfully suggest that you’ve been living underground. It’s everywhere. 

The largest source of electricity in the United States comes from power plants burning coal, oil, and natural gas. Together these fossil fuels account for about 75% of the electricity in the US, and they also pump tons of greenhouse gases into the atmosphere. If something is to be done about climate change (and by the way it’s pretty well accepted in the scientific community that humans are responsible for the rising global temperatures), we must come up with a way of generating electricity that doesn’t pollute as heavily. 

My answer for this problem is nuclear. It’s not just because I like physics and there’s really cool physics in nuclear power, but because I think it is the most practical solution, especially over the next few decades. Let’s face it: hydro is limited geographically, and neither wind nor solar is reliable on a large enough scale to contribute significantly. Not to say they won’t be, but probably not in the next 20 years. 

There are probably some doubters out there, so here’s some interesting facts about nuclear power you may not have known. 

• A nuclear power plant has zero carbon emissions. Yes, zero. The only thing a nuclear plant releases is steam.
• A nuclear plant is almost completely automated, and the computers won’t let anything bad happen. Like a commercial airliner, the safety systems on a nuclear plant are doubly or triply redundant, which means if something fails there’s at least one layer of backup. 
• The reactor is contained in a concrete dome. Even if something bad were to happen to the reactor, the radiation would be completely contained in the dome and would not have any impact on the surrounding environment. 
• You get less background radiation if you live near a nuclear plant than if you live near a coal power plant. Turns out coal has some radioactive isotopes (in small levels) that are released into the atmosphere when it is burned. 
• The spent fuel, although it is highly radioactive, can be recycled, which cuts down on waste. Fuel that cannot be recycled can be stored safely in repositories such as the one proposed at Yucca Mountain in Nevada, but the political process has not allowed the facility to become operational.  
• Half of the fuel used in the US’ nuclear plants since 1989 has come from decommissioned nuclear weapons. That accounts for 10% of all the electricity generated in the US in the last 20 years. 

I’m pretty sure I showed this video to all my classes some time ago. It shows progressive images of the relative sizes of the planets and a few stars. I always enjoy watching it. 

I found this article this morning (thanks to Mr. Minnich for sending it my way) that has a little discourse on the video. It’s an entertaining read and it made me giggle. 

I love optical illusions. This little snippet from a Bill Nye video shows several of them, and I thought it might alleviate the boredom of vacation for a while. Enjoy!