pondělí 13. února 2012

Disadvantage of plastic windows

If I have to compare plastic and wood windows, then the advantage of plastic windows are:
  • they don't expand nor shrink, thus they don't need periodical readjustment as wooden frames
  • they don't suffer from imperfections typical for natural materials
  • it is easy to make holes into the frame for cables
The disadvantages of plastic windows:
  • you don't see into the window frame. And sometimes the window is just a plastic frame, which is hold together with the glass. Once I have seen a plastic window which was left open for a week. And next week the glass slid out from the frame because the plastic frame couldn't hold the heavy glass for so long time. In another case the customer asked for a glassed wall and decided to make it from plastic windows. During the normal wind (30 km/h) the middle of the wall moved forward and backward by 8cm because the frame was armored just with a wire. I don't say that plastic frames are less rigid than wooden frames, that's not true. But when you decide to choose plastic frame, look at the armoring of the window - there should be massive pieces of metal, which can withstand a lot of force (nice trick - try to hang yourself on the frame, if the frame survives, you may have found a good frame).
  • you don't know how durable is the plastic. The problem is that the manufacturers attempt to save the cost and put a lot of filling material into the plastic because the filling material is much cheaper than plastic. Unfortunately the filling materials often decrease the quality of the compound. The common problem is color instability (white turns into beige or grey - just look at your old PC to get the idea), cold problems (plastic can get fragile or porous in cold) and aging instability (simply some plastic doesn't last long, for example Tesco bags are designed to last just one year and then they turn into ash).
  • while it can be good that you can easily make holes into the frame burglars abuse it as well. They make a hole into the frame, find the lever from the handle, pull the lever the right direction and the window is opened. It's easy (you just need an accumulator screwdriver, a headlamp and pliers) and fast (it can take 5 minutes for unskilled labor, 30 seconds for a professional).

čtvrtek 9. února 2012

Why People Believe in Global Warming

I am not going to discuss whether global warming exists or not but I would rather explain why people like to believe in existence of global warming.
  1. People like to be scared. When they are kids they like when people do "baf" on them. When they are 15 years old they like to watch horror movies with people dissected by a chainsaw. And when they are 20 they like stories about communism, terrorism and global warming.
  2. People don't like unexplainable. Back in time when there was a storm people used to say "the Gods are angry". When the summer was too dry they used to say "the Gods are angry". When the winter was too long they used to say, ... well, I think you have got it.
    But in these days not everyone is religious and Bible explains only flood. And despite billions dollars spend on science weather forecasts are unreliable. Fortunately, we can explain extreme weather by global warming.
  3. People don't like when they can't control things. When the winter was too long people used to sacrifice a goat or a virgin to placate the Gods. Communists use to promise that we will rule the wind and rain. But these days it's hard to find a goat and neither science gives as tools to change the weather.
    But wait. If global warming is changing the weather and if global warming is caused by humans than we have finally got control over the weather! All we have to do is lower carbide dioxide emissions and it will lower global warming!
Overall, global warming is a beautifully fabricated story worth of spreading, regardless it's fact or fiction.