Wishful Coding

I’m starting a study group in Loenen (Gelderland), and you are invited. The primary focus of the group will be on programming and computer science.

After having been to several learning institutions, I found out it’s not something that works for me. I like to study at my own pace, whatever it is that I want to study.

However, I found that collaborating and peer learning make things a lot more fun. Therefore I want to organize a study group, to learn and create together.

Do you want to join? To work out the details, and to facilitate further discussion, I have created a wiki and a mailing list.

I sketched out a few things that’d work for me, but if you feel like “I want to join, but…”, speak up, nothing is set in stone.

You know these helium balloons? They float because helium is lighter, less dense then air. You know what is even lighter than air? No air at all!

I came across the idea on this website, where he notes

I haven’t done any math, but I assume this isn’t feasible at the present time.

I have done some math, or rather, asked Wolfram Alpha.

So, first of all, how heavy is a cubic meter of air anyaway?

Ok, so our balloon can weigh just over a kilo and still float. But what is the surface area of a balloon of that size?

Almost five square meter. So with one kilo of matter, we need to make a balloon of nearly 5 square meter surface area.

Aww, not looking good. If we use aluminum¹, we can make a shell of a tenth of a millimeter thick. This shell will have to resist 1 bar, which equals 10 newton per square centimeter.

I just picked this up from Wikipedia, but presumably this means the stress on the shell will be 3162 newton per square millimeter.

Now, remember that this is a vacuum, so while a pressurized balloon retains it shape because of the pressure, the biggest problem with our vacuum balloon is the buckling force.

The smallest dent, a gust of wind, or even gravity itself, will cause the balloon to implode. I asked my dad², and he asked his engineer, how to calculate this force. Third order magic.

I recently bought a Kindle, and I love it! It takes some effort to convert scanned PDF books, but other than that, you just email stuff to Amazon, and it gets delivered.

For long articles, I found that Instapaper has a ‘Read Later’ bookmarklet, that can be configured to send a digest to my Kindle.

The only hard part was Google Reader, so I thought I’d share that with you. Reader has a ‘Send To’ feature that can send articles to Kindle, but you have to go trough all the articles manually.

We’ll have to involve an extra step, called Instascriber. Instascriber lets you automatically send up to three feeds to Instapaper. Not enough for all my feeds, but luckily Reader has an RSS feed hidden deep down.

The broad approach is to collect your feeds in a public place in Google reader, so you can put the RSS feed in Instascriber, which submits them to Instapaper, which in turn emails them to Amazon, which then finally delivers the issue on my Kindle.

Finding a public RSS feed in Reader is a bit tricky. Information I found about public folders and tags seemed outdated, with the new interface. What you need to do is, go to ‘Browse for stuff’, and create a bundle there.

When you’re done, you need to figure out how to get the feed. I did this by clicking ‘Add a link’, to get to the public page. Depending on your browser, you might already see the RSS icon there. For FireFox, it can be found by pressing CMD+I and going to the ‘Feeds’ tab.

For reference, this is what my feed looks like http://www.google.com/reader/public/atom/user%2F09723460687514136094%2Fbundle%2Fkindle

From here on, it’s standard form-filling and do-as-you-are-told business.

First register at Instapaper, and set up Kindle delivery according to their instructions

Finally, register at Instascriber, enter the Reader feed, and enjoy reading!