The reading passage describes three reasons against the use of burning mirror by Greeks of Syracuse as a weapon to defend themselves when the Roman navy attacked this port city 2200 years ago. And the lecturer rejects them as unconvincing.
The first reason in the reading states that the ancient Greeks lacked the technology for producing the burning mirror, thus they could not have developed such an advanced device which should have been relatively wide with a precise parabolic curvature. However, the professor clarifies that the mirror did not have to be made by a single large sheet of copper, the Greeks actually combined dozens of small mirrors for the purpose and Greek mathematicians already possessed the knowledge about the parabolic curvature at that time. Therefore, they could have invented the burning mirror.
Against the second reason described by the passage which suggests that the mirror was impractical because it took a long time to burn the boats, the lecturer points out that the experiment supporting that reason was based on the assumption that the ancient Greeks concentrated the sunlight on the wooden part of the boats in order to catch fire, but there was another material on them that is extremely inflammable even if the ship is moving. Hence, the mirror did not take more than few seconds to set the ships on fire.
Finally, in regard to the third reason presented by the reading which claims that flaming arrows were already used for the same goal and as effective, so there was no reason for building the mirror, the professor explains that the Roman soldiers were familiar to these arrows and the mirror was more effective since it was a surprising attack to them.
The reading passage
describes
three
reasons
against the
use
of burning mirror by Greeks of Syracuse as a weapon to defend themselves when the Roman navy attacked this port city 2200 years ago. And the lecturer rejects them as unconvincing.
The
first
reason
in the reading states that the ancient Greeks lacked the technology for producing the burning mirror,
thus
they could not have developed such an advanced device which should have been
relatively
wide with a precise parabolic curvature.
However
, the professor clarifies that the mirror did not
have to
be made
by a single large sheet of copper, the Greeks actually combined dozens of
small
mirrors for the purpose and
Greek
mathematicians already possessed the knowledge about the parabolic curvature at that time.
Therefore
, they could have invented the burning mirror.
Against the second
reason
described
by the passage which suggests that the mirror was impractical
because
it took a long time to burn the boats, the lecturer points out that the experiment supporting that
reason
was based
on the assumption that the ancient Greeks concentrated the sunlight on the wooden part of the boats in order to catch fire,
but
there was another material on them
that is
extremely
inflammable even if the ship is moving.
Hence
, the mirror did not take more than few seconds to set the ships on fire.
Finally
, in regard to the third
reason
presented by the reading which claims that flaming arrows were already
used
for the same goal and as effective,
so
there was no
reason
for building the mirror, the professor
explains
that the Roman soldiers were familiar to these arrows and the mirror was more effective since it was a surprising attack to them.