Are
You Interested In The Number 7 ?
**************************
7 is a
prime number.
1, 3, 4,
7, 11, 18, 29...
A Lucas
number.
= 2 - 1
A Mersenne
prime.
There are seven days in a week.
Hept- or
Sept- means seven. A heptagon is a figure with seven sides and a heptachord
is a
seven-stringed
musical instrument. A septennium is a period of seven years and September
used to be
the seventh
month in the year, but not any longer.
The Seven
Deadly Sins are avarice, envy, gluttony, lust, pride, sloth and wrath (listed
in alphabetical
order,
not order of wickedness).
Among many
things that come in sevens are the Seven Wonders of the Ancient World,
the Seven
Sisters,
Shakespeare's Seven Ages of Man, the Seven Levels of Hell, and the Seven
Dwarves.
Netball and water polo are both played with teams of seven players.
In Britain the 20p and 50p coins both have seven sides.
Under British
law, when you reach the age of seven you can open and draw money from a
National
Savings
Bank account or a Trustee Savings Bank account.
7-Up is
a soft drink. It was invented in America in the 1920s by Mr C L Griggs
of Missouri who
originally
called it Bib-label Lithiate Lemon-Lime Soda. With a name like that sales
were poor even
though
the drink tasted good and so Mr Griggs set about changing the name. After
six attempts he
came up
with 7-Up, or so the story goes. 7-Up is also the name of a card game.
John Sturges's
1960 western The Magnificent Seven is about a Mexican village that hires
seven
gunmen
for protection from bandits. The story is based on an earlier Japanese
film made in 1954 -
Akira
Kurosawa's The Seven Samurai.
Roy Sullivan,
a park ranger from Virginia, USA is the only person to have been struck
by lightning
seven
times. Between 1942 and 1977 he was struck on top of his head (twice),
his eyebrows, his
shoulder,
his chest, his ankle and his big toe. Although he received hospital treatment
for his injuries, he
was extraordinarily
lucky to escape death from so many strikes.
Ask a number
of different people to give you any number between one and ten, and most
will choose
seven.
Ask people to name their favourite number between one and ten, and again
most will say
seven.
In 1956
George Miller wrote an article The Magical Number Seven Plus or Minus Two:
Some
Limits
on Our Capacity for Processing Information. This showed that the amount
of information
which
people can process and remember is often limited to about seven items.
One example of this is
called
the digit span.
Ask someone
to repeat back to you exactly what you say. Begin with four digits chosen
at random
e.g. 6
6 2 5. Then give them five digits e.g. 5 8 4 5 0, then six, and so on.
Carry on increasing the
number
of digits until they make a mistake. The longest number of digits they
get completely right is
called
their digit span and for most people this is about seven digits.
Suppose
someone is shown a pattern of dots for a very short time - just one fifth
of a second - and
they are
asked to count the number of dots they saw. If the number is less than
seven they will be
right
almost every time, but with more than seven, they will make lots of mistakes.
Seven is
not really a magic number, but does have an uncanny way of appearing in
all sorts of odd
situations.
A version of this familiar problem appears on the Rhind papyrus written in Egypt about 1650 BC -
As I was going to St Ives,
I met a man with seven wives,
Each wife had seven sacks,
Each sack had seven cats,
Each cat had seven kits:
Kits, cats, sacks and wives,
How many were going to St Ives?
Home