Hello. This is 6 Minute English from
BBC Learning English. I'm Neil.
And I'm Sam.
What do shopping with a credit card,
finding love through internet
dating and waiting for the traffic
lights to change have in common?
Hmmm, they all involve computers?
Good guess, Sam! But how exactly
do those computers work?
The answer is that they all
use algorithms - sets of
mathematical instructions
which find solutions to problems.
Although they are often hidden,
algorithms are all around us.
From mobile phone maps to
home delivery pizza, they
play a big part of modern
life. And they're the
topic of this programme.
A simple way to think of
algorithms is as recipes.
To make pancakes you mix flour,
eggs and milk, then melt
butter in a frying pan
and so on. Computers do
this in more a complicated
way by repeating mathematical
equations over and over again.
Equations are mathematical
sentences showing how two
things are equal. They're
similar to algorithms and
the most famous scientific
equation of all, Einstein's
E=MC2, can be thought of as
a three-part algorithm.
But before my brain gets
squashed by all this maths,
I have a quiz question for
you, Sam. As you know,
Einstein's famous equation
is E=MC2 - but what does the
'E' stand for? Is it:
a) electricity? b) energy?
or c) everything?
I'm tempted to say 'E' is
for 'everything' but I
reckon I know the answer:
b - 'E' stands for 'energy'.
OK, Sam, we'll find out if
you're right later
in the programme.
With all this talk of
computers, you might think
algorithms are a new idea.
In fact, they've been
around since Babylonian times,
around 4,000 years ago.
And their use today can be
controversial. Some algorithms
used in internet search engines
have been accused
of racial prejudice.
Ramesh Srinivasan is Professor
of Information Studies at the
University of California.
Here's what he said when asked
what the word 'algorithm'
actually means by BBC World
Service's programme, The Forum:
My understanding of the term
'algorithm' is that it's not
necessarily the bogyman, or
its not necessarily something
that is, you know, inscrutable
or mysterious to all people -
it's the set of instructions
that you write in some
mathematical form or in
some software code - so it's
the repeated set of
instructions that are
sequenced, that are used
and applied to answer a
question or resolve a
problem - it's a simple as
that, actually.
Some think that algorithms
have been controversial,
but Professor Srinivasan
says they are not necessarily
the bogyman. The bogyman
refers to something people
call 'bad' or 'evil' to
make other people afraid.
Professor Srinivasan thinks
algorithms are neither evil
nor inscrutable - not
showing emotions or thoughts
and therefore very difficult
to understand.
Still, it can be difficult
to understand exactly what
algorithms are, especially
when there are many different
types of them. So, let's
take an example.
It's autumn and we want to
collect all the apples from
our orchard and divide them
into three groups - big, medium
and small. One method is to
collect all the apples together
and compare their sizes.
But doing this would take hours!
It's much easier to first
collect the apples from only
one tree - divide those into
big, medium or small - and
then repeat the process for
the other trees, one by one.
That's basically what
algorithms do - they find
the most efficient way to
get things done, or in other
words, get the best results
in the quickest time.
Mathematics professor Ian Stewart
agrees. Listen as he explains
how the algorithm called
'bubble sort' works to BBC
World Service's programme,
The Forum:
Think of when your computer
is sorting emails by date and
maybe you've got 500 emails
and it sorts them by date in
a flash. Now it doesn't use
bubble sort, but it does
use a sorting method and if
you tried to do that by
hand it would take you a
very long time, whatever
method you used.
Professor Stewart describes
how algorithms sort emails.
'To sort' is a verb meaning
to group together things
which share similarities.
Just like grouping the
apples by size, sorting
hundreds of emails by hand
would take a long time.
But using algorithms,
computers do it in a flash -
very quickly or suddenly.
That phrase - in a flash -
reminds me of
how Albert Einstein
came up with his famous
equation, E=MC2.
And that reminds me of your
quiz question. You asked
about the 'E' in E=MC2.
I said it stands for
'energy'. So, was I right?
'Energy' is the correct answer.
Energy equals 'M' for mass,
multiplied by the Constant
'C' which is the speed
of light, squared.
OK, let's recap the vocabulary
from this programme, starting
with 'equation' - a mathematical
statement using symbols to
show two equal things.
If something is called a 'bogyman',
it's something considered
bad and to be feared.
'Inscrutable' people don't show
their emotions so are very
difficult to get to know.
'Efficient' means working
quickly and effectively
in an organised way.
The verb 'to sort' means
to group together things
which share similarities.
And finally, if something
happens 'in a flash', it
happens quickly or suddenly.
That's all the time we have
to discuss algorithms. And if
you're still not 100% sure
about exactly what they are,
we hope at least you've
learned some useful vocabulary!
Join us again soon for more
trending topics, sensational
science and useful vocabulary
here at 6 Minute English from
BBC Learning English.
Bye for now!
Goodbye!