How are the numbers for G-codes devised and what do they mean?

Edited by Julie Lewis
August 13, 2005

G-code is a predefined decimal numbering system that includes, date, channel selection, starting time, program length and start / stop commands read by the decoder built into many video recorders. G-code commands are sent from the remote control and are used to quickly program VCRs to record certain shows at certain times. For convenience, the most popular viewing times use the shortest numbers.

Paul Roberts, Lake Cathie

Basically it's shorthand for "Why bother, the programme's never on time anyway".

Sandy Parkinson, Hilton WA

Who cares? Has there EVER been an occasion when a TV program starts at the advertised time? If you use a G-code to program your video, you're almost CERTAIN to miss the beginning of the show!

Phil Jacobs, Seaforth

Do sunrise and sunset refer to the centre, top or bottom of the sun at the horizon?

There are three kinds of twilight, Civil, Nautical and Astronomical.

Navigators are concerned with Civil and Nautical twilight.

Sunrise is the first appearance of the sun's upper limb, (the upper or lower limb refers the upper or lower edge of the sun or moon as appropriate) above the visible horizon. Similarly, sunset is the disappearance of the upper limb below the western horizon.

Twilight is the period before sunrise when darkness is giving way to daylight,and after sunset when the opposite is true.

The duration of the twilight is chiefly a function of the observer's latitude; it increases with an increase in latitude.

Mick Costelloe, South Coogee

Sunrise and sunsets and, indeed, those of all heavenly bodies occur when the centre is at the horizon. However, due to the irritating phenomenon of atmospheric refraction we see things that are below the horizon. So these events we observe occur after and before respectively and their times are thereforce dubbed "apparent".

Tim Bowra, Rozelle

In theory, the exact moments of sunrise and sunset are when the top of the sun's disk is just visible on the horizon. In practice, these times cannot be calculated precisely because they depend on local topography, altitude and atmospheric conditions. Forecast sunrise and sunset times are therefore defined to occur when the centre of the sun is geometrically 50 arcminutes (a little less than one degree) below a horizontal plane, which accounts for the average apparent radius of the sun (16 arcminutes) and the average amount of atmospheric refraction at the horizon (34 arcminutes).

David Roche, Helensburgh

Is soap intrinsically always clean?

Soap works with a chemical and physical action. It is generally alkaline which is antibacterial and antifungal, and during washing the soap acts on the acidic oily layer on top of skin to dissolve it, the physical action of washing in water then rinses off the oil and microorganisms with it, making the skin clean, but not sterile. The value of washing with soap and water in preventing transmission of infections was discovered by Sammellweiss, an Austrian physician, and by Florence Nightingale in the nineteenth century, although doctors at the time didn't initially believe either of them. However when you leave wet soap, the wet film on the surface does become contaminated with bacteria, so leave the soap to dry when used and use plenty of it when washing.

You've obviously never seen a little bouquet of pubic hair left perched on top of the shower soap.

Laura Perusco, Gerringong

Yes, because it acts as an emulsifying agent. It disperses one liquid into another one that normally does not blend. This means that while oil, which attracts dirt, doesn't naturally mix with water, soap can suspend it so it can be removed. A soap molecule has a distinct head and tail. The tail grabs the dirt, the head grabs the water and the dirt and oil are washed away.

Paul Roberts, Lake Cathie

No, haven't you had a peek of Desperate Housewifes?

Steve Barrett, Glenbrook

Whoever asked this has clearly never looked at the soap after someone else has attempted to use it to remove engine grease. Not to mention the way hairs stick to soap...

Stephanie Roberts, Denistone

Why did African-American activist Malcolm X choose "X" as his surname and not some other letter?

Malcolm Little would have learned at school that "x" stands for the unknown in mathematics. He adopted X in the 1950s to represent his unknown African family name instead of the arbitrary Anglo name selected by the owner of his slave ancestor. The tradition of "x" being used as the symbol for the unknown in mathematical equations dates back at least to the 16th century. Some sources suggest that it comes from the Italian or Spanish spelling of the Arabic word for "thing". Incidentally, when Malcolm X converted to orthodox Islam in the 1960s he took the name El-Hajj Malik El-Shabazz.

Jack Alexander, Randwick

It was common practice among Nation of Islam followers to change their surname to "X" since they no longer wanted the surnames given to them from past slave masters. However, they did not know who their ancestors were and therefore did not know their real surnames. In mathematics, X represents an unknown variable, just like their real surnames.

Jerry Chang, Surry Hills

From the autobiography of Malcolm X.

The Muslim's "X" symbolised the true African name that he never could know. For me, my "X" replaced the white slave master name of "Little" which some blue-eyed devil named "Little" had imposed upon my paternal forebears.

Joseph Lee, Belfield

Malcolm Little changed his name to Malcolm X in 1953 while serving seven years in prison for burglary. While in prison he converted to Islam and became a member of the Nation of Islam lead by Elijah Muhammad. He believed that white society actively worked to keep African-Americans from empowering themselves and achieving economic,political and social success. He considered his surname Little to be a slave name and chose X to signify his lost African tribal name. Why X? - because X is the mathematical symbol for the unknown quantity.

Ian Grant, Bella Vista

Because his full surname was Xerxes?

Sandy Parkinson, Hilton WA

The Nation of Islam (or Black Muslims as commonly known) have used the "X" for a number of years, as a replacement for their inherited "slave names". The Black Muslims assert that the letter X in mathematics and science represents the unknown, thus symbolising the fact that African-Americans do not know their true African names, taken away when their ancestors were brought to the Americas and replaced with the names of slave-owners. Malcolm adopted the X (to replace his last name -Little) when he joined the Nation Of Islam.

Paul Batters, Farmborough Heights

Malcolm X chose the "X" to signify his unknown real African surname, rather than keep a name given to his family by slave-masters. Why X? I guess it is a common symbol to represent the unknown and mysterious. In Malcolm X's words, though: "To take ones X is to take on a certain mystery, a certain possibility of power in the eyes of ones peers and ones enemies ... The X announced what you had been and what you had become: Ex-smoker, Ex-drinker, Ex-Christian, Ex-slave."

D MacPherson, Enfield

When the American slaves were emancipated, they received "40 acres and a mule" from the government, with which to start a new life. They had to sign for their property, but as most were illiterate, these men made their mark by drawing and "X" on the document. Malcolm X took this as part of his name in homage to his forefathers.

Sandy Barker Maroubra

Do racehorses know they are supposed to win or do they just think they are out for a nice gallop with their mates?

The horses at the front do, those at the back don't.

Kate Murphy Dungog

The answer could well lie with the whip.

Peter Dresser, Coonamble

Horses are as variable as people and can be roughly separated into the same categories of keen competitors, occasional performers and born losers. Look around you at work and you will see one or two fellows just out for a nice gallop with their mates. They make a bit of an effort now and again to impress the boss but the money invested in them is usually wasted. They belong in the glue factory but, oddly enough, they will retire to the same lush pasture as the compulsive pace-makers.

Paul Roberts, Lake Cathie

It now depends if they have been down to the local for a snort.

Con Vaitsas, Ashbury

Racehorses are extremely intelligent: every conveyance knows that it should try, until it hears that it is carrying my hard-earned.

Bob Dengate, Bathurst

Horses race to win because most horses think they are being chased by a sabre-toothed tiger and the one in front won't get eaten.

My horse being the exception to the rule of course.

Juliet Wight-Boycott, Thirroul

Where do all the decorative pebbles come from?

Obviously it depends on the origin and type of the stones, but the source of the smooth round stones is probably similar in most countries: river beds and the sea shore.

On many occasions in various parts of Indonesia, I have seen people working hard for long hours and very little money collecting these stones. On stony (rather than sandy) beaches, men will trundle back and forth into the surf scooping up buckets of stones and gravel, and then plop themselves down just out of reach of the waves and sort through bucket after bucket for suitable specimens. Others will then use various grades of chicken wire to sort the stones by size, and others will sort the colours. Then they are carried to the village, 2 buckets at a time suspended at either end of a long rod resting on some poor, wizended, skinny, but very strong fellow's shoulders, the rod flexing alarmingly with each step of his bare feet on the stony path. It is the same in the river bed, except that groups of men will dig very deep (and dangerously unstable) holes, because that's where the smaller stones are to be found. It's hard and obviously back-breaking work.

Eventually, through various middlemen, retailers and exporters in the big cities buy the stones - however all that hard work that may see a small bag of black pebbles retail for $10, garners only 20 cents per bucket of sorted stones to the people who pick them up from where they may have lain for hundreds of years. Tough work, if you can get it.

Troy Rich, Jakarta


Why is sarcasm the lowest form of wit?

If re-entry to the Earth's atmosphere is so dangerous, why doesn't the space shuttle go slower?

Why are tennis players "seeded" rather than "ceded"? Surely the order of importance is a matter of succession, derived from the word "cede"?

What is the origin of the military salute and why is the navy one different to the air force one?

Why is a broad, expansive mind called "catholic"?

