<span>1.</span>I believe the correct answer is in 16th
century.
Graphite pencils were first used in 16th
century when the large graphite deposit in Borrowdale, England was
discovered. Graphite sticks were originally
wrapped in string, but later were inserted into hollowed-out wooden sticks (in
Italy). But, before graphite pencil, in ancient Rome, writers were using stylus,
a thin metal rod to leave a light, but readable mark on papyrus and after that
a predecessor of graphite pencile, the silverpoint.
<span>2. </span>I believe the correct answer is crystalline
allotrope of carbon.
Graphite is a crystalline allotrope of carbon, a native
element mineral, and a form of coal. Graphite is the most stable form of carbon
and can be divided in four types: amorphous graphite, lump graphite (or vein
graphite), highly ordered pyrolytic graphite and graphite fiber. Graphite may
be used for batteries, steelmaking, brake linings, pencils etc.
<span>3. </span>I believe the correct answer is: hard black
pencil, most standard use of pencil.
HB scale is the second (after numerical) scale for
determining the characteristic of the graphite pencils. Letter “H” means that
the pencil is hard and letter “B” means that the pencil is black. If the pencil
would be HH it will mean that the pencil is extra hard, but if the pencil is B,
it is blacker, soft pencil.
<span>4. </span>I believe the correct answer is: the pencil is
harder.
When the letter “H”
which represents the hardness of the pencil is increased, the hardness of the
hardness of the pencil is increased. For example, 3H pencil is twice harder
than the H graphite pencil. The same rule applies for the blackness and the
softness of the graphite pencil.
