Archive for August, 2007

As Seen at WWDC

Sunday, August 26th, 2007

A gigantic Papier-mâché BNC Connector near the Marina. I have no idea from whence it came or what on earth it could conceivably be used for.

And before you ask – no, I did not find the female connector.

Fun with Dust-Off…

Tuesday, August 21st, 2007

Dust-off canister

No, not that kind of fun – I’m talking about fun with endothermic reactions!

You see – Dust-Off isn’t really compressed air (pressurized Nitrogen is pretty boring) but is in fact liquid difluoroethane. So what happens when you release a liquid with a boiling point well below that of room temperature (-24.9 °C)?

Lets find out:
Calulations

You get a reaction that will absorb an awful lot of energy from it’s surroundings (you can freeze stuff).

Getting more to the point- around here, in the summer, I come across a fair bunch of house spiders and, while I don’t mind them outdoors, can’t have them wandering around indoors. The problem is that they can be pretty tough to catch (especially the small ones) and mashing them makes a mess (especially the big ones). However, with the help of the aforementioned fluorocarbon, dealing with insects is a breeze.

All you need to do is give the can a good shake, tilt sideways and aim and fire. If you do things correctly the nozzle (moistened by shaking) will produce a directed spray of very fine difluoroethane droplets that, due to the their large surface area, vaporize rapidly – making the immediate surroundings very cool.

Bonus: on a humid day, your very likely to see frost form from the spray!

It’s all about the Brackets, Baby!

Thursday, August 9th, 2007

Obj-C hands picture

With C4[1] starting tomorrow (which I, sadly, won’t be at). It seems apropos that I put out my graphical rendering of Rentzsch’s Obj-C sign from C4[0]. There you are!

(more…)