electricity.pdf
electricity.mp3
Neil
Hello This is 6 Minute English from BBC Learning English I’m Neil
Georgina
And I’m Georgina
Neil
Now, Georgina, what do you know about AC DC?
Georgina
You mean the Australian rock’n’roll band? Well, their 1979 hit ‘Highway to Hell’
stayed at No1 for eleven weeks…
Neil
No, no, no - not that AC DC, Georgina! I’m not talking rock music here, I’m talking
electrical currents – alternating current - AC, and direct current - DC, the two
ways in which electricity flows
Georgina
Oh, I see No, I don’t know anything about that ACDC!
Neil
Well, don’t worry because in today’s programme we’ll be finding out some quirky
facts about electricity - how it differs across the world and why some countries
have more complicated electrical systems than others
Georgina
Hmmm, I have noticed that when I travel to another country I need a converter
plug to connect my laptop Is that something to do with AC DC?
Neil
Yes, it could be Of course, electricity itself doesn’t change from country to
country
Georgina
No It’s an invisible, natural force at work in everything from lightning storms to
the electrical sparks firing our brains
Neil
But although it happens naturally, one scientist was credited with discovering
electricity Who? That’s my quiz question – who discovered electricity? Was it:
a) Thomas Edison
b) Alexander Graham Bell, or
c) Benjamin Franklin
Georgina
I’m not a qualified electrician myself, Neil, but I’ll say c) Benjamin Franklin
Neil
OK Well one person who definitely is a qualified electrician is BBC presenter
Gareth Mitchell So when BBC Radio 4’s ‘Science Stories’ sent him to meet
electricity expert Keith Bell, the conversation was, shall we say, sparky
Keith Bell
Standard frequency in the US is 60 hertz, actually I think in the US on the
mainland US, main continent, there are three different synchronous areas So
although it’s around 60 hertz, at any moment in time these three different areas,
because they’re not connected to each other, will be going at a slightly different
frequency There are bigger differences elsewhere So in Japan for example, I
think one of the main islands is at 60 hertz and the other half of Japan is at 50
hertz
Gareth Mitchell
That’s a bit of a pickle!
Neil
Generally speaking, frequency means how often something repeats In the case
of electrical currents, frequency is the number of times an electrical wave
repeats a positive-to-negative cycle
Georgina
It’s measured in hertz (Hz) In the US power is at 60 hertz and in the UK it’s
around 50 hertz
Neil
So the US and UK are not in the same synchronous area – not occurring together
at the same time and rate, or in this case, frequency
Georgina
Which means that to safely use a British electrical device in America, I need to
convert the power supply If not it won’t work or even worse, it could break
Neil
And a broken laptop could leave you in a bit of a pickle – an informal expression
meaning a difficult situation with no obvious answer Here’s Gareth and Keith
again talking about more differences
Gareth Mitchell
I’m pretty sure when I go to the United States, my electric toothbrush doesn’t
charge up at 60 hertz - 110 volts, but my laptop still works Maybe you have no
comment, Keith, but I’m just saying…one of these anomalies that I seem to have
found
Keith Bell
So, I’m not sure about the electric toothbrush but I know a lot of our power
supplies for laptops and stuff are solid state, you know - they’ve got electronics
in that do all the conversion for you, so basically it ends up with a DC supply into
the machine itself So there’s a little converter in there and it’s designed so it
doesn’t care what frequency the AC input is
Neil
Gareth noticed that in the United States his toothbrush doesn’t always fully
charge up – get the power needed to make it work
Georgina
Electric toothbrushes which don’t fully charge and differences between electrical
frequencies are good examples of anomalies – things which are different from
what is usual or expected
Neil
But with modern technology these anomalies are becoming less and less
commonplace For example, computer companies have started making laptops
with solid state electronics – electronics using semiconductors which have no
moving parts and can automatically convert different electrical currents
Georgina
Meaning I can use my laptop to google the answer to your quiz question!
Neil
Ah, yes I asked you which scientist was credited with discovering electricity And
you said?
Georgina
c) Benjamin Franklin – and I already know I’m right because I googled it on my
solid state laptop! To show that lightning was electricity, Franklin attached a
metal key to a kite and flew it during a thunderstorm The key conducted
electricity and gave him a shock!
Neil
Hmm, not an experiment I recommend trying at home! Today we’ve been talking
about anomalies – or unexpected differences in electrical currents between
countries
Georgina
Electrical currents are measured in frequencies – the number of times a wave
repeats a positive-to-negative cycle These can be different if two countries are
not synchronous – occurring at the same rate, for example Britain and the
United States
Neil
Different frequencies may mean your electrical devices like your laptop, phone
and toothbrush won’t properly charge up – get the power to function, in other
countries
Georgina
And having a phone with no power could leave you in a bit of a pickle - a difficult
situation
Neil
Fortunately many modern devices use solid state electronics – non-moving
semiconductors inside the machine which automatically convert the electrical
current
Georgina
So you’ll never miss another edition of 6 Minute English again!
Neil
That’s all for today See you soon at BBC Learning English for more interesting
topics and related vocabulary Bye for now!
Georgina
Bye!
VOCABULARY
frequency
how often something repeats; electrical current frequency is the number of times
a wave repeats a positive-to-negative cycle
synchronous
occurring together at the same time, place or rate
a bit of a pickle
informal expression meaning a difficult situation with no obvious answer
charge up
get the power needed to work; recharge
anomalies
differences from what is usual or expected
solid state
electronics using semiconductors which have no moving parts and can
automatically convert different electrical current
