Last weekend I roller-bladed 12.5 miles around London in a group of over a hundred people. The friday night skate really is great fun. It’s very well organised. They have ‘marshals’ wearing luminous tops, who keep everyone together, and stop the traffic while everyone zooms past. They have a map of the weekly route, weather cancellation information on the website. The route is always in two halves, the second half being faster, for the better skaters.

You have to be pretty good at roller-blading before you should attempt it, because they go fast and they huddle together in a big herd of inter-tangling legs, but if you are a competent street skater, and you find yourself in London on a Friday, I heartily recommend it!

When I’m manically cutting and pasting between windows I sometimes find that MS Outlook suddenly sends my email before I’ve finished typing it. The reason is that they’ve cleverly made ‘Ctrl Enter’ a keyboard shortcut for the send command. In any other type of window, it just behaves like ‘Enter’.

One of these days this is going to get me in serious trouble. It already came close. A while back I sent an email to some guy, to compliment him on his website and ask him a question. Only trouble is I got as far as ‘Nice website’, then accidentally sent the email, complete with a company ‘signature’ which contained an advert for one of our products.

I would normally have deleted this signature, since its a bit crap, and of no relevance to anyone outside the Tibco integration industry (i.e. most people I email), but as it was, this guy received an email which looked like nothing but an advert from my company.

Naturally enough he quickly came back at me with a vicious flame, and I had to explain what an ‘Ctrl-Enter’ing idiot I am. Thankyou microsoft. Thanks for that embarrassment. I am only thankful he didn’t flame the company sales department (which is what I would do in that situation), imagine the explaining I would have to do then.

[UPDATE: Turns out there is a way to switch off Ctrl-Enter keyboard shortcut in outlook. I’m discovering this while also finding that Yahoo! mail AJAX interface somehow does Ctrl+Enter sending. Gah!]

You know those crappy little plastic stirring things which are like teaspoons but without the spoon? Well this office here has those. I decided I should take one and re-use it, for stirring many cups of tea, rather than disposing of it. But then I had it on my desk, and so naturally I developed a habit of chewing on it. The stirring things are made of brittle plastic, so every time I get a cup of tea (approx 3 per hour) I get a new stirring thing, I stir my tea, and I then destroy it by chewing on it, and flecks of saliva covered plastic get stuck behind the keys on my keyboard.

…well now all that’s changed. They’ve introduced plastic spoons, which are better than stirrers, not only because they can be used for eating yoghurts, but also because the plastic is less brittle. One spoon can withstand over a week of chewing. I heartily recommend them to any office supplies manager who is contemplating the spoons vs stirrers decision.

Colds come in three phases. I have now made it to phase 3.

Phase 1 : Very runny nose. You can feel germ ridden nose juice trickling down your throat and into your stomach. As a result of this your throat starts to be irritated, and you start to feel queesey.

Phase 2 : After sleeping with acidic slime in your throat it is sore and tickly. This contributes to the involuntary caughing and sneezing which is giving you a dizzying headache, and spreading germs everywhere.

Phase 3 : The storm has passed. There is some risidual irritation causing the occasional caugh, but some immune response has definately kicked in, and your nose is now producing inexplicable quantities of thick gloopy snot.

This is my big disco ball. It’s about the size of a football. I’ve got a little motor thing for turning it too. Unfortunately I don’t have a suitable light for shining on it. Not just any light will do. I need a spot light really. A normal light bulb doesn’t work very well for two reasons:

• Firstly it lights up the whole room, so the spots of light on the wall dont look so impressive because the wall is already lit. We do have some directional lamp things which work better, but in general a normal light bulb is not good for dingy disco darkness
• Secondly a normal bulb creates rays of light which diverge as they radiate outwards. If the bulb is a couple of metres away from the disco ball then you might think that the divergence would be negligable, but no! Unless the light rays are completely parallel, you’re wasting your time. The reflections form faint fuzzy blobs on the wall, rather than impressive well focused spots.

…but maybe I’m wrong about the whole parallel thing. Obviously the correct equipment for the job is a spot light. It doesn’t take a PHD in disco-lightology to tell you that. But what’s so special about a spot light? Do these have parallel rays? No they dont, because otherwise they wouldn’t be able to make big 2 metre wide spots, big enough for a ballerina to stand in. But the light is focused, so that you can put silly shaped filters on them (or dog shaped shadows with your hand). A projector is the same. A projector would be good for disco balls too.

The staircase trick

I have had some success with my disco ball. If I turn off all the lights in the house except for the light on the top floor landing. This particular lighting configuration doesn’t occur often, so it was quite an exciting discovery when I noticed the nice well focused spots on the darkened living room ceiling. Light beams were travelling 3 stories down through the narrow gap in the middle of the staircase and striking one side of my disco ball where it hangs above our sofa.

Direct Sunlight

The most impressive thing to try with a disco ball is direct sunlight. I might organise a disco party on a sunny day to make use of this. Sunlight creates perfectly focussed bright spots. Roll the ball from side to side in a patch of sunlight near the window, and it feels like the whole room is rolling!

The circular square disco ball spot phenomenon

Here’s a physics question for you. Given the correctly focused lighting conditions discribed above, why is it that the spots on the wall are circular? I dont just mean blobby roughly circular shapes. They are perfect crisply defined circles. Reflections at about 10-15cm from the disco ball are square shaped, matching the shape of the mirrors exactly, as I would expect. So how come the long distance spots are circles? Surely this is an important question which science must have an answer to. It’s right up there with “how did the universe begin?”