Trivia

A caffeine rush never fails to make me want to blog. Tried Belgian Chocolate Ice Blended instead of the usual The Ultimate at Coffee Bean. Damned sweet, but it's rich. Nice. =)

 

Anwz today's entry will be ramblings as usual. It will start off with a little piece of trivia and end off with a little piece trivia.

 

(Don't worry, they are not the same trivia. Though I originally intend to make it so. Hee. =P)

 

Trivia Number 1

Have you ever wondered what the piece of rectangle on your laptop, which allows you to move the cursor using your finger, is called, and how it works? I've been musing on the above questions during one of my fits of 'boredness' at the office. I tried rubbing the rectangle of my company's laptop with a rubber, my wallet's leather, and a small cute furry Australian 'Hugging Kola Bear' (whose is hugging a stick of glue). The rubbings might had excite / stimulate the Kola Bear, but they sure didn't make the cursor move. And I wondered why. So, I did a little research today, and here's the answer:

 

The rectangle is called a Touchpad, and it works by sensing the changes in capacitance created when your finger touches the pad. Put simply (as I understand it), the touchpad is made of a conducting metal grid (determining location) covered by a non-conducting plastic membrane. Your finger / body is a (grounded) conductor. If you know your physics well, 2 conductors separated by a thin non-conductor causes charge built-up, and that charge difference between the conductors is called capacitance. And the Touchpad senses the change in capacitance on the metal grid as your finger moves around, and moves the pointer accordingly.

 

Kola Bears (toy ones) doesn't work because they are insulators. Try metals, they works (given enough surface area).

 

I tried explained this to some pple. They gave me the 'Human body is conductor meh?' look. Then I would give them the 'Ya hor. Why har?' look. Afterall human body isn't exactly made of metal, isn't it? So, I did a little research, and hence, I present to you, Trivia Number 2!

 

Trivia Number 2

Actually the answer is very simple (I've just forgotten it). Given enough voltage, current can pass through almost anything, even insulator. Strictly speaking, materials ain't exactly divided into conductor or insulator (or semiconductor, for those who are engineers). Conductivity isn't so black and white, there are a range of greys in between. Human body is less conductive than conductors like metals, but is more conductive than insulators like plastics/ceramics - somewhere in the middle of the spectrum... but still, it conducts current in that situation nevertheless , so, human body is a conductor.

 

Frankly speaking, I hate grey areas. That's why semiconductor is one of my most lousy subjects. T_T