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� AMAZIG ANSWERS TO CURIOUS QUESTIONS -------------------

How do What's the What is

barcodes work? difference jailbreaking an

arcodes are a machine-readable way of between hi-def iPhone?
Bwriting letters and numbers. A laser is
shone onto the barcode and the reflected pple ensures the quality of software
light can be interpreted by the barcode and normal TV? A available for the iPhone by screening
reader. There are many types of barcodes, but ecently, TV took the biggest leap in before release through the built-in App Store.
the ones most commonly found in Rpicture quality since the arrival of colour There are other applications that will run on an
supermarkets use a row of lines of different back in the Sixties. High definition TVs offer iPhone but haven't made it into the App Store.
widths. The different widths represent images up to four times as detailed than those There are several ways you can get round the
different numbers. In the UK many items are by standard TVs. Standard definition (SDTV) restrictions and install third-party software.
coded with a GTIN - Global Trade Item televisions display the picture in a series of The phone is then said to be jail broken.
Number. This allows the manufacturer to print interlaced lines. Interlacing is showing
the barcode on the packages which can then alternate lines every other frame. This saves
be read in many different shops. The numbers bandwidth but reduces quality. Analogue TV
are unique to that item. The barcode only has has 625 interlaced lines of which 576 contain How do
a number, but no product information. That is picture information. •
held in a database which the retailer can Broadcasters experimented with analogue mzcrowaves
access at the point of sale. It also means that HDTV but found it used too much bandwidth
shops can set their own prices and change to be viable. With the introduction of digital cook food?
them easily without re-labelling every item on television broadcasting, digital compression
the shelves. can be used to shrink the HDTV signal to a icrowaves are a form of
reasonable size. The output of modern TVs is Melectromagnetic wave like any other
described using numbers. For example, 720p radio wave. Microwave ovens heat the water
means 720 progressively scanned lines. molecules inside foods, which gives off heat
That's much more detail than 576i or SDTV energy that can be used by other molecules in
and even better pictures can be had with TVs the food to warm them up as well. This is why
that can display 1080i (i for interlaced) or pasta and rice often need water added in
even 1080p (p standing for progressive). order to heat them up.
''Recently, TV took

the biggest leap in What are
picture quality since pixels?

ixel is short for Picture Element.
the arrival of colour PWhen we see graphic images on
How do fans back in the Sixties'' digital devices the display divides the
screen into thousands or millions of
make you feel pixels, arranged in rows and columns.
Each pixel has its own address in this
cooler? What is grid and is represented by dots or
squares. Pixels build up a sample of
an original image and are the smallest
can feel very refreshing on a hot day, but distributed
S witching on a fan and feeling a nice breeze component of a digital image. The
more pixels used to represent an
what is going on? Is the fan taking some of the computing? image, the closer it will resemble the
heat energy away? In a small, perfectly original. The number of pixels used to
insulated room, switching on a fan can create an image is often referred to
increase the temperature in the room as fans D istributed computing is a term used to as the 'resolution'. The best digital
usually have a motor which gives out heat. describe any process conducted by many cameras have the highest pixel count
The reason why fans make you feel cool is due separate computers connected by a network, because they produce a higher­
to something called the wind-chill effect. all working towards the same goal but not quality image. In colour images a
Blowing air over your skin causes quicker necessarily doing the same job. A famous pixel typically comprises three or four
evaporation of sweat which allows your heat example was SETI@home which used idle colour dots - a red, a blue and green.
energy to escape much quicker than normal, time on home computers to process large When these colour dots converge,
making you feel cooler. Let's hope we'll be amounts of radio telescope information one they build coloured pixels.
needing them in the summer! chunk at a time.

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