There's still some life in an antique brain

Without referring to any text book I recently constructed the deduction of Snell's Law for refraction from the assumption that light traveling between two points follows the path that minimizes the time taken.

It is reassuring to note that my brain still works, to some extent.

Revelation

Browsing through the local branch of Waterstones I came upon an intriguing volume called 'Quantum Mechanics The Theoretical Minimum'. Following a reference in that book I discovered a website with a series of lectures on theoretical Physics with various supporting materials.

The object is to explain basic physical ideas as simply as possible, avoiding both the superficiality of the popular books that avoid Mathematics and therefore explain very little, and the obscurity of the texts that use quite abstruse mathematics without making any serious attempt to explain what they are doing. What I have read so far seems to be quite a good attempt. Two things that had been puzzling me are now clear, and I look forward to more enlightenment.

Stray Hairs

I can't abide feeling hair over my ears. Now and again an obstinate strand drifts over an ear and resists my attempts to push it away.  I reach for the nearest pair of scissors and snip it off.

Most women and many men style their hair so that it completely covers their ears. How can they bear it!

Linked Numbers

I've just realised that, to quite a close approximation, the mass of the earth in kilograms is given by

M = pi²*A  where A is Avogadro's Number

Remembering Mini-Skirts

The current discussion of 'up-skirting' has reminded me of the days of mini-skirts.

In the late 1960's I was teaching a class of FE science students, all boys aged 16 or 17. Their 'General Studies' was taught by one of the teachers of English, a young lady who wore very short skirts and, to the delight of the students used to sit on one of the desks while she taught, so after each class the lads would announce the colour of her knickers, though without mobile phones they had no corroborative photographs.

Exhausted by Idleness.

Often I feel sleepy in the afternoons, but only on days when I'm not doing anything in particular. If I do some gardening, tidy the attic, or cook something elaborate, I stay wide awake and don't feel at all tired.

To summarise, nothing can be rather tiring.

Today is Tuesday

I make the announcement for the benefit of anyone else whose temporal bearings are disturbed by bank holiday Mondays.

When Monday is so much like Sunday, it is easy to mistake Tuesday for Monday. Occasionally my disorientation lasts for most of the week. However I'm making a special effort today, and am sure it's Tuesday, and that tomorrow will be Wednesday.

A Fuss About Information.

I have quite a few interests and have therefore arranged for various organisations to send me information about their activities. Recently I've been irritated to receive numerous messages telling me that 'data protection' legislation requires that the flow of information must be discontinued unless I confirm I still want to receive it. That seems to me impertinence on the part of legislators. If I change my mind about a source of information, I can easily have those emails discontinued, without the intervention of self important politicians.

Check Your Insurance Charges

It will soon be time to renew my house insurance, and I noticed the premium had risen a good deal in the last two years.

I rang to question it, and secured a reduction of about £190 in the premium.

A Happy Coincidence

From time to time the flow of news in the media is disturbed by some event of no great consequence which still attracts unreasonable attention.

Today two such events coincide - the royal wedding and the cup final, so the tranqility of our thoughts is disturbed only once even though there are two distractions.

Happy day!!!

Learning from Poirot

I recently gave into an impulse to buy a mango, my memories of the last time I wrestled with one having become faint.

As I wondered how to deal with it I remembered a television adaptation of a Poirot mystery, in the course of which the resourceful detective demonstrated the use of a dessert spoon to remove the stone from a mango, which he then turned inside out exposing the flesh.

Although I didn't make as neat a job as Poirot, who probably had support from the television studio's mango evisceration team, I found that mango much easier to eat then others I have dealt with.

A Devious Television Set

I recently bought a new television set. After using it for a week or two I found that it is sometimes very slow to respond to its remote control.

Using a combination of reading glasses and magnifying glass I was just able to read the instructions, and noted that the set can be connected to the Internet. So far as I know no connection has been made, but it might have detected the WiFi signal in the  house and attempted to connect.

Unplugging the set and leaving it unplugged for several hours seems to have restored correct operation, at least for now.