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10

SECTION 1

7

Now read the whole text again in order to expand the main points with essential information and fill in

the second column.

8

Now scan the text and circle the words which answer these questions.

a

In an electron, is the charge positive or negative?

b

Is the charge positive or negative in a proton?

c

Is it true or false that a neutral condition means the positive and negative charges are equal?

d

Is it true or false that electrons orbit around the nucleus in an atom?

Main ideas

Development of main ideas

SEARCH READING See

Reading strategies

on page 16

SCANNING See

Reading strategies

on page 16

heat

calore

matter

materia

shell

strato, scudo

static charges

cariche statiche

TECHNICAL ENGLISH

electrical charge so it is electrically neutral. Negative

and positive polarities indicate two opposing

characteristics, which seem to be fundamental in all

physical applications. Just as magnets have a North

and a South pole, so electric charges have opposing

polarities termed positive and negative.

It is the way in which electrons and protons – the basic

particles of electricity – are arranged

2

that determines

the electrical characteristics of all substances. Each

combination of electrons and protons makes one

particular type of atom. This is the origin of atomic

structure. All electricity is produced by the movement

of small particles which have an electric charge:

positive or negative.

Usually, objects have equal numbers of positive and

negative charges. If the electrical charge on a proton

is equal and opposite to the charge on the electron,

the atom is electrically neutral. However, unbalanced

charges also create a form of electricity.

For example, this sheet of paper has electrons and

no evidence of electricity,

because the number of

electrons

equals

the

number of protons.

In this case the opposing

electrical forces cancel

each other out, making

the paper electrically

neutral.

The neutral condition means

that these opposing forces are exactly

balanced

3

. Changing the balance of forces offers

evidence of electricity. In order to do this, electrons

and protons have to be separated. When the charges

move they create an electric current.

1

is made up of

: formed by

2

arranged

: put in a neat, required order

3

exactly balanced

: a condition in which different elements

are equal or in the correct proportion

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