Archive for the ‘Education’ Category

Tired of crabs, lizards, and actor masks?

The procedure to change the icon used in a Gridworld project is as follows:

Create the desired graphic as a 48×48 pixel GIF image.

Save the image in the same folder as the .class file for the bug or critter or actor.

For example, if you create a class called testcritter that extends critter using Eclipse and assuming the default location for the workspace, place the graphic in the bin folder located in …/project/workspace.

On a Windows 7 system the file location for a user named Bob would be:


Before you make another purchase online, can you trust that website with your credit card information?

Here are some things to look for:

  • Check your browser’s address bar. Don’t trust the site with your personal information if the web address doesn’t begin with https. Also look for a lock symbol on the address line.
  • Did you arrive at the site by clicking on a link someone sent you via email? Before you enter credit card info, check with the person who sent you the link to make sure it is legitimate.
  • Double check the web address in the address bar. Is it accurate?
  • Does the website display information that makes it more credible such as a physical address or logos of accountability sites like TRUSTe and BBBonline.

None of these, by itself, guarantees your protection from fraud but you can minimize the chances by doing due diligence.




Browsing through computer ads, I see a lot of home computer systems are equipped with a 1 Terabyte hard drive. If you’re like me, that really doesn’t mean much. I have no sense of how much space that is.

Here is a visual illustration. Glancing on my bookshelf, one of the thickest books I own is “War and Peace.” It is availabe as an electronic file on Project Gutenberg. The plain text is 3.1 MB (megabytes). There are 1024 megabytes in 1 gigabyte. So I can fit about 330 War and Peaces on a gigabyte. There are 1024 gigabytes in a terabyte.

So a 1 terabyte drive will hold 337,920 copies of War and Peace.

For a frame of reference, the Kindle store clains to have over 950,000 books most of which are not as big as War and Peace (plus Kindle files are smaller than plain text files). So if I bought every book in the Kindle store (assuming no pictures), I could fit them on three 1 terabyte drives.

Inkjet printers are cheap. They practically give them away. But do they? Here is my attempt to discover exactly what an inkjet printer costs to own and operate:

HP Officejet 4500 – $59.99 on Newegg.

Black ink (200 page yield) costs $13.99

Color ink (360 page yield) costs $24.99

Let’s say I print 2,000 pages for the year, I will buy 10 black cartridges regardless of how much color I print because black is used every page. (10 x $13.99 = $140)

If I use color sparingly but print photographs periodically, I will likely use at least three color cartridges (3 x $24.99 = $75).

Total ink cost for a conservative year of printing on a $50 printer – $215.

Now you know why the printer was so cheap. No, they’re not giving it away.

Java Bitwise Or

Posted: January 11, 2010 in AP Computer Science A
Tags: , , , , ,

Java Bitwise Or

System.out.print(15|32) returns 47

which is tricky because you assume that addition is taking place. But the following line

System.out.print(11|33) returns 43

This is not addition, it is called the bitwise Or. To illustrate:

Step 1: Convert the integers to binary lining up the digits in place value.

11 = 001011
33 = 100001

Step 2: Or the digits in corresponding place values (right to left or left to right doesn’t matter in the case of Or)

0 0 1 0 1 1
OR 1 0 0 0 0 1
Result 1 0 1 0 1 1

When using an Or, if both digits are 0 the result is 0. All other cases result in 1.

Step 3: Convert to decimal if necessary.

101011 = 43

Day 11:

Can you believe I made the nice list this year? I can prove it –  check out this video: Santa’s video

Greg’s Teacher deal of the day – Just in the Nick of time (get it? – Nick?). Finally, a netbook below $250 again. A netbook is a small notebook (not a book about nets). It has a low-voltage processor and a small screen. It’s handy for traveling, connecting to the Internet and using Office apps – what you use your computer for most of the time.

This one has the usual stuff: card reader, webcam, wireless, 1 gig of memory, 160gig hard drive. The downside is it has a 3 cell battery. That means it will last 2.5 hours between charges at best. Still, if you need to put a computer under the tree, this may be your best bet. I still think prices will come back down after Christmas if you can wait.

Lenovo netbook – $230 and free shipping at Newegg

Greg’s Teacher download of the day – You bought the computer and plugged it into the Internet with NO ANTIVIRUS? And now you’re calling me because you could build a bicycle faster than the thing boots up. (Why is it that when people describe how slow their computer is they feel the need to list all the things they can accomplish before it boots up?)

Here’s my secret to getting the bugs out and it won’t cost you anything but some time.

Download and install Avast. Answer yes to the option to scan at restart. Once it has dealt with your viruses and malware, uninstall it and install Microsoft Security Essentials. This will stay active on your computer and help to prevent further problems.

Avast download

Microsoft Security Essentials download

Bryan’s Tech deal of the day – My deals today don’t really have a theme. ADD could be the theme I guess. At any rate. I’m sure you’ve thought to yourself, “Man I wish my shoe had a calendar on it.” Make that dream a reality with Calendar Tape (9.99). Make anything (yes, even your shoe) a calendar. Also, a Math Clock (26.99). Make reading time require a calculator. At least it would require a calculator for the likes of me. And now, for something completely different. A Remote Light Switch (24.95). Turn on/off anything you can plug in. It’s dimable (although I won’t advise dimming that brand new LCD TV you just got) and can attach to a wall if you feel like being pedestrian with your REMOTE switch. It doesn’t support a ground wire (aka that three prong plug thingy), so no refrigerators, computers, etc.

Bryan’s Tech website of the day – You’re staring at your computer wondering where in the web you want to go. Stop puzzling and go to Give it some of your favorite things and it’ll find websites about them! WARNING: Extremely addicting.

Day 10:

Greg’s Teacher deal of the day – Set your phasers to stun! Looking for the ultimate gift for the techno-nerd on your list. He (I’m gender stereotyping but let’s be real, the only woman I’ve ever seen handle a phaser correctly is Uhuru) has to have this for some serious street cred.

Star Trek Original Series Black Handle Phaser – $15

This is the real deal. Notice it’s a black handle phaser. Clearly superior to the blue or green handle phasers. And if you need further support of the authenticity, just read the product reviews from people who have purchased it. (Seriously – you have to read these)

Greg’s Teacher download of the day – Looking for a fun way to review a unit with your class? Trying to make it like a game show to engage the kids? What’s the game show we all try to imitate for this kind of thing? Fear Factor…what? No, no no…. think like you’re over 30. Jeopardy, of course. And I know, in an effort to integrate technology, you’d like to do this with Powerpoint. If only you had step-by-step instructions. Well here they are:

Powerpoint Jeopardy templates and instructions

No more excuses. Get busy.

Bryan’s Tech deal of the day – Bring a little cheer to your desk with the USB Fiber Optic Christmas Tree (9.99). Plug it in to any USB port and it glows with Christmasy joy.
Bryan’s Tech download of the day – Tired of Outlook running slowly or not at all? Try Thunderbird. It’s made by the same people who make Firefox, the second largest browser in the world. Fast, full featured, and easy to use.