7
In the past, many cities and towns were built alongside waterfalls (a
primary source of mechanical energy) that turned water wheels to perform
work. Before electricity generation began over 100 years ago, houses were lit
with kerosene lamps, food was cooled in iceboxes, and rooms were warmed by
wood-burning or coal-burning stoves. Beginning with Benjamin Franklin's
experiment with a kite one stormy night in Philadelphia, the principles of
electricity gradually became understood. Thomas Edison helped change
everyone's life – he perfected his invention – the electric light bulb in 1879
Prior to 1879, direct current (DC) electricity had been used in arc lights for
outdoor lighting. In the late-1800s, Nikola Tesla pioneered the generation,
transmission, and use of alternating current (AC) electricity, which can be
transmitted over much greater distances than direct current. Tesla's inventions
used electricity to bring indoor lighting to our homes and to power industrial
machines.
Despite its great importance in our daily lives, most of us rarely stop to
think what life would be like without electricity. Yet like air and water, we tend
to take electricity for granted. We use electricity to do many jobs for us – from
lighting and heating/cooling our homes, to powering our televisions and
computers. Electricity is a controllable and convenient form of energy used in
the applications of heat, light and power.
NOTE-MAKING
Effective note-making is important. Notes are for your personal use.
They form part of your document that you will return to later. So, you should
create your own style of taking notes. Here are some tips for you:
•
Concentrate on the main idea and note only the key points, not word
for word.
•
Write only the key words, not complete sentences. Don’t worry about
spelling, grammar and punctuation. You can leave out articles (a/ the),
prepositions (of/ to) etc.
•
Use symbols and abbreviations to save time.
•
Emphasize the most important information by underlining, circling,
highlighting and so on.
•
When you miss something, leave some place.
Let's recall words on the topic “Electricity”. The game “Snowball”
(the student names the word and gives the translation; the next one repeats
the word and the translation of the first and adds his (her) variant etc.
Look at the words in the list; you may use them in the game.
