Virtual Teacher Newsletter  No. 103  19th February 2005 ­  MEGAPIXEL RACE




1. Welcome

2. Mind Candy



5. Technical Stuff ­ MEGAPIXELS AND DPI

6. Web Site Focus ­ 6 THINKING HATS


8. Great Sites

9.  Readers' Requests/Comments

10 Next Issue

11. Code of 'Netizens'

12. Tips


1. WELCOME EVERYONE. Lots of info about Megapixels, DPI,

and digital images this issue and a start into some DeBono

adventures.  Also, take a look at Libbyıs new website and let

me know what you think.  Great to see an Australian author taking

advantage of multimedia delivery, should excite a lot of kids.

Have a great fornight.



³If you never change you mind , why have one? If you never

changed your mind you could just have a sign saying: ŒSame

thinking a last month, same ideas too!²

Edward DeBono, How to have a Beautiful Mind, pp166, 2004


This is mad, do it properly, no cheating

Count the number of 'F's in the following text





Managed it? Scroll down only after you have counted them!


> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

> >

How many? Three?


Wrong, there are six - no joke!

Read again! The reasoning is further down.

> >

> >

> >

> >

> >

> >

> >

The brain cannot process "OF". Incredible or what? Anyone

who counts all six 'F' on the first go is a genius, three is


Comedy On Tap


Learning is not compulsory. Neither is survival.

-- W.Edwards Deming


NOTE: In theory, there is no difference between theory and

practice, but in practice there is a great deal of difference.



Check out the tests for over 60 digital cameras here



Free Stock Photos for Schools




A megapixel is simply one million pixels. What's a pixel? A pixel is

the single, square "picture element".


DPI ­ dots per inch ­

300 dpi ­ good for photographic quality reproduction

1(when you put in the memory stick and set the resolution the

camera will tell you how many shots will fit on that stick)

150 DPI Low resolutions ­ doesnıt stand up to close scrutiny,

you start to get


Jaggy pictures ­ AVOID THESE

72 DPI ­ is the resolution for the Web



Well have purchased six thinking hats from

There website isnıt quite running yet, but their store is a great treat.

so I have the hats and will be working on parallel thinking this term.

I tried them out on the family last night, and they werenıt doing a

lot of thinking as they were to busy laughing at my choices.

So far a lot of fun.

Lesson Plans for Schools

Let me know what you are doing with this thnking tool.


7. ŒYou oughta be in Pixelsı was a title of an Article from

Edutopia November /December 2004

A lot of folk as about this ­ and we are currently seeing the great

megapixel camera marketing race, as usual VT gets to the heart of

it here, with some great mathematics too.



Manufacturers are in a great pixel race at the moment.  With MORE,

being better. Basically ­

1 megapixel is for the novice (web and 150dpi low res pictures)

2 megapixel is just fine for standard sized postcard images.


3. megapixels is great for 5 x 7 printable images intermediate

4 megapixels is really for your amateur enthusiast. Good 10 x 8


5 megapixels and above youıll find files will be slow to load and

youıll need serious computer hardware to process your files

All cameras can be set to take images of various resolutions of

jpeg and the higher end cameras can shoot Tiffs and RAW files.

The pros use RAW files, the information id direct from the sensor

with no additional processing, they give the best quality for photo

manipulation purposes.



A good camera is one that will take the sort of photos you want. 

If you just want postcard sized images then a 3 megapixel camera

is just fine. If you just want web images to send via email and small

pictures for students to use, then a 1-2 megapixel camera is fine. 

Make sure you like the way it feels in your hands. Some of the

smaller cameras are awkward, particularly for children to use. 

You need to be able to hold it well, with places for fingers that arenıt

in front of the lens.  I like bigger cameras like the Mavica for younger



1. I have used a 2 megapixel mavica with primary school  children,

just great. Itıs is a good size, and the images are great.  The floppy

disk drive allows each child to take their pictures and then their disk

and load up their computer, without tying up the camera.  Of course

the floppy drive has a life of about 2 years, but after that you can use

a memory stick.

2. I use a 4 megapixel  Sony Cybershot for school photos, this

camera gives great results for A3 size images, and the image quality

is excellent.

Cybershot, (approx $350, Mavica from $800)

3. For Pro cameraıs the Canon 10D (upgraded now to the 20D)) is

a knock out giving great images that can be enlarged on wide format




1. I use Photoshop, it is the industry standard for photo manipulation.

Great for graphic designers and Year 11 & 12 Graphic arts students and

photo enthusiasts.


2. Photoshop Elements is a cheaper cut down version, it is great. 

Suitable from middle primary through to adult.  Easy to use and

some spectacular features, at fantastic price.  with a similar

interface to photoshop itself, this program allows easy migration

to the more advanced version.


3. Donıt have any money ,just use Microsoft word. Go to view

menu, go to toolbars, go to picture, click on the image and

away you go.


4. DPI ­ dots per inch

For a 300 DPI print (super sharp photo intended for viewing up close)

Print Size       Resolution needed for 300 DPI print

4x6                  about 2 MP

5x7                  about 3 MP

8x10               about 6 MP

11x14             about 14 MP

13x20             about 23 MP


For a 150 DPI print (photo quality when viewed at "arms length")

Print Size       Resolution needed for 150 DPI print

4x6                   about 0.5 MP

5x7                   about 1 MP

8x10               about 2 MP

11x14             about 3.4 MP

13x20             about 6 MP



Image File Sizes

As you can see, the more pixels you have per inch on your photo,
the larger the file size will be. If you need to calculate the size of your
files beforehand, you will need the following information:


1. How many pixels the image has

2. How many color channels your image has (ie: Greyscale has one,
RGB (red, green, blue) has three and CMYK (a print format) has four.
If you plan to publish your picture on the internet, your format would be
RGB. If you plan to have your pictures printed, you would then select CMYK.


For our example, we will use an image that is 640 x 480 pixels, using
RGB as our color channel.


You will need to multiply 640 by 480.

640 times 480 = 307,200

Now, take 307, 200 and multiply it by 3 for your color channel.

307,200 times 3 = 921,600 = .9 MB

This amount tells you how many bytes of information you have in your image.

This is for any lossless file format like tiff.  Saving files as jpegs reduces
file size considerably.


Image Arithmetic

Memory Costs of Images



In schools I like to use only one memory stick, they seem to walk. 

For private use it is handy to have several so that when one is full

you have a spare and continue to take photos ­ like additional rolls

of film. 

Buy a memory stick for school to suit the maximum number of

photos you will use in any session or on an excursion. If you take

a photo of everyone in the class at a postcard size resolution say

30 x 2 x 2MP ­then a 128MP memory stick should be just fine. 

You can then download this onto your computer and erase the

memory stick for future use. (when you put in the memory stick

and set the resolution the camera will tell you how many shots

will fit on that stick)




Libby Hathorn ­ you know ­ great Australian  Childrenıs author

has a new online resource full of games, stories, and integrated

activities.  I have just taken delivery of the CD material as well so

will be trialing it over the next few weeks.  Look forward to updates

­ so far it looks great.  Take a look and tell me what you think. If

anyone has used this material please write in with your comments.



Infection Detection Protection

"Microbes are the oldest form of life on Earth. Some types have

existed for billions of years. These single-cell organisms are invisible

to the eye, but they can be seen with microscopes. Microbes live in

the water you drink, the food you eat, and the air you breathe. Right

now, billions of microbes are swimming in your belly and crawling on

your skin. Don't worry, over 95% of microbes are harmless." This

entire exhibit (from the American Museum of Natural History) is

fabulous, but the best clicks are the Shockwave games with names

like Bacteria in the Cafeteria and Infection!

Developed by the American Society for Microbiology,

introduces middle school students to microbiology with colorful

images and friendly text. They even have a special section on

hand washing, where I learned that although 94% of Americans

say they wash their hands after using the bathroom, only 68%

really do. Ughh! Other excellent clicks are the science experiments

for home or classroom, and the career section.


Microbe Zoo

Using a zoo metaphor, Microbe Zoo explores microbe ecology,

the study of microbes in their environment. Created for upper-elementary

and middle school students, the site is divided into five environments:

Animal Pavilion (with instructions on building a dung chamber in

Poo Corner) , DirtLand (Who knows what evil lurks in that dirt pile?
Microbiologists do.), Snack Bar (hmm . . . yummy yogurt), Space

Adventure (microbes on Mars?) and Waterworld.



Hi Cathy, At Heatley Secondary College in Townsville(NQ) we're

experimenting with Moodle on our school network and it's fantastic. 

It can be used by the novice teacher or as a great training

ground for future BlackBoard course creators (BlackBoard is

EdQLD's superb site for students and teachers).

It's taken me, a keen English teacher but slow ICT user, a few

months to get my head around.  The kids love Moodle and that's

the main thing.  Of course the price is brilliant too.  '

Gotta love Open Source.  Cheers, Andrew Jones.


I asked Andrew to describe a few of the things he was doing with Moodle:


Using Moodle for the first time....Nothing too brilliant


1.  Journal writing to a topic.  Students who previously hated writing

enjoyed writing to a topic and reading the multiple responses to what was

said on the discussion thread.  I've never seen them write so much.  I

remember this last year because I couldn't stop one student writing - he was

4 years below his reading age and usually a non-writer.

2.  Evaluation of lessons and unit.  A private yet public paradox of

analysing aspects of learning and my teaching. Again the discussion thread

seemed to become a more personal and honest response to a review of what was

completed in class.  Hard copy paper responses never achieved the same

detail from the whole class.

3.  I have linked handouts and resources which lead students to the

completion of tasks as word documents and are in turn stored digitally (on

hard drives).  This saves paper and allows students to work at own pace.

4.  Other teachers have uploaded music and sound effects onto the server

(remember only 2MB uploads allowed as yet).  Students accessed these files

and used a multitrack and free sound editor - Audacity also on server due to

file size) to create radio commercials.


There are many other features I'm still learning but they look impressive

such as the multiple choice tests and the ability to submit assessment.  I

think there's a Moodle conference in Adelaide again this year.  I'd love to

go and see what others are doing.




Thanks a lot for sharing this.  If you have any great new things

you are doing, even if you think they are not so ıbrilliantı as

Andrew says, send them along. And by the way Andrew ­ it is brilliant.


What are the meanings for  the maths terms-

A barn

and a

Circular Mil


Lauren Kiernan


Any takers for this one ­ what do you think.


Hi Cathy, a fellow teacher recommended that I subscribe to virtual

teacher and so I am contacting you, hoping you can help.

My edumail address is

I am a teacher at Wonthaggi SC and I am at present investigating

options in setting up an intranet that is also accessible from the

internet, with appropriate security features in place. I have made

some attempts at investigating commercial solutions such as

Blackboard, Uniservity and the MyInternet products, as well as

being aware that Glen Waverley SC (Victoria) have developed

 their own solution. I am also interested in following up on the

way schools use Moodle and any other approaches that have

been successfully used along with costs etc. Do you have any
contacts/information articles from Virtual teacher that might be

relevant or that might further my quest?

Cheers, Mike.


I have put Mikeıs email address in the newsletter ­ perhaps

some of you may want to contact him direct. Please cc me

on any correspondence.


10.  NEXT ISSUE ­ Next Issue more about DeBono ­ and

hopefully Moodle. Please take the time to share your great

computer adventures with VT. Donıt forget the





11. Code of the 'Netizens'

This Newsletter is not free, despite the misleading advertising

above. The Fee is now due. Each week you must help one

colleague on the Internet who has less knowledge than you.

Help that person even if you have to visit their classroom or

do a little research and get back to them. Trust me, this will

help a lot of people get their computer classrooms running better.

OK I'm trusting you!!!


12. TIPS

1. Double click on highlighted URLS to open in browser.

2. Send in your Questions, Questions will be published with

Answers, send in your Answers, if you have expertise to share.

3. Nominate a brilliant site for review and inclusion in this


4. Nominate a fantastic school site for review and inclusion in

this newsletter.

5. Make contact with other schools using fantastic programs.

6. Prepare and innovative article for this newsletter.

7. Tell 2 colleagues about this newsletter.


The opinions expressed here are purely those of the editor,

Cathy Brown. All other small print clauses apply. Such as:

Use at your own risk. Nothing in life is guaranteed. If it doesn't

work for you send me an email.

Editor: cathy brown


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