An internet simulator

I’ve been working my way through’s CS Principles widgets and having a terrific time.  There has been some great thought and originality put into the design and implementation of the individual widget. 

I’ve worked my way down to the Internet Simulator.

If you’re interested, you’ll undoubtedly be advised to read the lesson plans first.  These not simple activities without some background and understanding but then the internet isn’t a simple thing to begin with!

This is a great simulator to gets hands on and learn about internet communications.

If you’re teaching the concepts, you’ll definitely want to add this to your toolkit.

A cipher widget

Another widget from takes you on the route to encrypting messages.  If you’re going to send a message, you need to do something a little sophisticated than what we did in elementary school which, if I recall, was as simple as moving each character in the message one ahead.  So, DOUG becomes EPVH.  Then, you’d pass the note along to a friend who would roll the characters back one to get the original message.  And, you’d also have rules like what to do when you use a Z or punctuation mark.

You’d be hard pressed to decrypt my message of the day.  “FBFVXGYXCFWOHAWKCEHINF”, I’ll bet.  But if you use the Vigenere Cipher Widget, it’s a piece of cake.

You need to provide a couple of things.

  • your message
  • your secret key

Then, let the widget do its thing.  

Using your secret key, it will take the original message and code it for you.

When you press the play button to make the magic happen, you can see the widget at work as it determines how to encrypt your message.  

Of course, the process can work in reverse as you take your encrypted message and decrypt it.  

Falling from this could be a great discussion about how you do banking and make online purchases safely.  Or even something as simple as sending an encrypted message to someone that they would later decrypt and read.  Of course, you don’t send the key and the text in the same message.

The best thing to happen?

After poking around for a little while, the inspired Computer Science student will want to write a routine of their own.  That always puts activities like this over the top.

A compression tutorial

Have you ever wondered how big things get sent across the internet so quickly?  I think that we all know that the answer is “compression”.  But, how does this compression work?  Does anyone remember the compression wars between ARC and ZIP?

Learning how is the goal in this tutorial from

Make sure that you watch the video first to get the most from the experience.  You’ll see the rationalization for why compression is used along with some real life examples.

The two big terms to learn and understand are “lossy” and “lossless”.  Do you know the difference?

Then, it’s off to the tutorial.  It’s an interesting and interactive concept.  You’re presented with some original text.

Now, the idea is to compress this information, starting at 240 bytes, by looking for patterns that could be repeated.  The patterns are replaced by symbols and you create a dictionary of the symbols.  That’s important because compression without a way to later decompress it is, well, pretty useless.

So, go looking for the patterns and the widget does the character substitution for you.

With these three substitutions, I was able to compress things by 33.75%.  If this text was to be sent, my 240 bytes is now 159.

The more compression, the better the speed.  Even after doing these screen grabs, I can see more ways to compress.

Sounds like a Computer Science classroom competition to me!

It’s a puzzle

Who doesn’t like a good puzzle?

Who hasn’t grown up and solved at least one jigsaw puzzle?  It’s a great rainy day activity.

Who hasn’t started to do a jigsaw puzzle only to find out that a piece or two has gone missing since the last time that you did the puzzle?

Take it all digital and enjoy the best.

Solving puzzles has such great thinking potential.  The puzzle, chosen properly, could reach into the mathematics classroom.  How about a little symmetry? 

Head on over to the Symmetry Puzzle section on the Math Is Fun website and pick one.

With the fall migration in progress, I chose the butterfly.

How many coffee tables does this digitally represent?

Now, to dispel the notion that I don’t actually work through the things that I write about on this blog…

I will admit to an OMG moment when the pieces started to move around after solving it.  I hadn’t had a chance to do a screen capture to prove that I had done it!

Have fun.

And, of course, poke around the rest of the website for many, many more engaging mathematics activities.

Another unique option

The past couple of days has seen me taking a look at a couple of mapping options.  To the list, I’d like to add a third – OpenStreetMap.

It’s considerably different from the other two which are managed by Google and Bing.  OpenStreetMap is created and built by the local community.  

Consequently, the community decides what gets added and, probably is more frequently updated as new locations become available.  Heck, just like Wikipedia, it could be edited by you and/or your students.  Details are available here.

I went back to Lasalle and started poking about.  What I found really intriguing here was the various mapping options available via the overlays.

It was kind of interesting to poke around and look at the cycling trails that have been built into the town’s infrastructure.

As for transportation, you can’t take a look around Essex County without checking out the uniqueness that is the Tunnel Bus from downtown Windsor to downtown Detroit.  It makes for interesting trips to Comerica Park, Ford Field, Cobo Hall, Greektown, and all of the other wonderful things to see in downtown Detroit.

Because the integrity is managed by the community, in theory, a chance in bus routes should be changed almost immediately.

One thing that I really enjoy with all three of the services are how clean the display is.  I think it’s important to recognize that there should be more than one tool in your mapping toolkit.  OpenStreetMap definitely is one to add.

Now and Then

I’m a big fan of Google Maps and, in particular, Street View.  I guess that I might be a very visual type of person because, when I want to go somewhere, I’d like to know a bit more than an address.  I’d like to know what the place looks like too.  That way, I know exactly when I get to my destination.  It’s also handy to check out the neighbourhood and see where the parking is as well.

It’s also intriguing to check out some personal history.

We were having a conversation recently about living in Toronto while going to the Faculty of Education.  I yearned for a look at the house where I stayed.  I still remember the address; after all, I had mail sent there for a year.  Off to Google Maps I went and I entered the address and then I dropped to Street View.  What turned up surprised me.

It was a new house or maybe even a small apartment building.  I certainly didn’t recognize it so I spun Street View around to see if could remember any of the landmarks.  In fact, there were quite a number of new buildings on that street but I distinctly remember the house right next door so I was sure that I was looking in the right spot.  I’m guessing my hosts had sold their house to a developer.

That’s not uncommon.  Ah, too bad I couldn’t have just one more look at the old place.

Not so quickly, Doug.  You can.

Street View has a history of all of the images that were ever taken of a particular spot!  I rolled back the clock and, sure enough, there was the old house.  Great memories of living in the apartment over the garage were the result.

How to do this?

I checked out some places locally that I knew had had some reconstruction and rebuilding.  Sure enough, they had some of the older images.

Just for fun, I checked out the Municipal Building in the town of Lasalle which has had a beautiful facelift in the past few years.  I drive by it regularly so I didn’t even need to know the address.  I just zoomed in and then dropped into Street View and adjusted so that I was close enough.

There’s the rough-ish address that I was at when I looked at the picture.  You’ll see that the Street View image was taken in June 2014.  To the left, though, there’s an icon that I’d describe as a clock with arrows circling it.  Click that.  That’s where the magic lies.

Full screen, you have the current image and a little thumbnail of the image appears in the fly out window.  Check out the bottom of the window for a little scrubber bar.  I slid it back to 2009.

Now, the angle is a bit different or maybe the building was moved a bit in its reconstruction.  You can drag things around and relive what was.

It’s a fantastic way to relive at least some of the ancient history anyway.

How about in your classroom?

    • Have you had a reconstruction of the school that the students could look back at?
    • What about all the places that you lived in when you went to university?  Are they still there?
    • If you work at a new school, what was there before the building was built?
    • How about your old house?  Do you remember that car parked in the driveway?

    The sky’s the limit when you start thinking personal history.

    Analysing writing

    If you read my post from yesterday, you would have seen this sentence.

    I also remember the big setups for television to start an activity with the knocking over of the first domino and then it cascades into knocking down the rest.  

    Those long in education will remember the endless activities of analysing sentence construction.  Quite frankly, I can’t remember the actual rules but do remember that it involved wavy lines, single lines, double lines, parentheses, and braces.  (although we called them round brackets and square brackets)  Then, there were arrows so that you could point various constructs to others.  

    It’s all just a blur to me now.  Maybe I should have paid more attention?  

    I never dreamed that I’d be so writing so much as I fidgeted in class.  I guess my English teachers were right after all.

    Recently, I played around with the FoxType website.

    A lot of memories came back!

    For example, the site will tear apart a sentence for you showing each of the component parts.

    There were lots of memories of the jargon of writing.  Prepositions, adverbs, subject, verbs, pronouns, … I was actually quite surprised and impressed with what I was able to remember.  There were new terms too like “Determiner” that I’d never used before.  However, the diagram above is quite nice in its explanation in context.

    That’s not the only feature.  I was curious to see how “Polite” my sentence was.  So, I gave it a shot.

    I guess I’m not as polite as I thought I was.  

    Or, maybe from a philosophical perspective, a blog isn’t meant to be polite.  At least, doug — off the record doesn’t pretend to be an objective research source.  It’s always written in the first person and always includes my opinions. 

    If you’re interested in language and writing, I’ll bet that you enjoy a wander through the website even though some of the features are still in beta.  

    It’s free for limited use and then there’s an option to pay what you think it’s worth.  As always, I’d love to hear your thoughts and thoughts in YOUR first person are always appreciated.