感恩父母的作文100字三年级英语作文：一次有趣的科学实验.doc

三年级英语作文：

一次有趣的科学实验

【一】

In

ancient

times,

many

people

believed

the

earth

was

a flat disc. Well over 2,000 years ago; the ancient Greek

philosophers were able to put forward two good arguments

proving that it was not. Direct observations of heavenly

bodies were the basis of both these arguments. First, the

Greeks

knew

that

during

eclipses

of

the

moon

the

earth

was

between

the

sun

and

the

moon,

and

they

saw

that

during

these

eclipses, the earth's shadow on the moon was always

round, they realized that this could be true only if the

earth

was

spherical,

If

the

earth

was

a

flat

disc,

then

its

shadow during eclipses would not be a perfect circle; it

would be stretched out into a long ellipse. The second

argument was based on what the Greeks saw during their

travels. They noticed that the North Star, or Polaris,

appeared

lower

in

the

sky

when

they

traveled

south,

in

the

more

northerly

regions,

the

North

Star

appeared

to

them

to

be

much

higher

in

the

sky.

By

the

way,

it

was

also

from

this

difference

in

the

apparent

position

of

the

North

Star

that

the Greeks first calculated the approximate distance

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