Answer 1:
In my opinion, one of the most important facts
about plastics is that the way we make them
determines how they behave.
Plastics are made of "organic"
materials, which means for the most part they
all contain the element carbon along with
hydrogen, oxygen, nitrogen, and a few
others. You can make plastics different from one
another just by changing whether a carbon is only
bonded with hydrogen or maybe a carbon is bonded
with another carbon. The plastic that makes
Tupperware has carbons next to an extra carbon
rather than all hydrogen while many plastic
grocery bags have more hydrogens next to carbon.
Besides just changing the elements that make
the plastic molecules, you can also change how the
material is processed - how it's heated and
cooled and stretched and squished while it's being
made. Styrofoam is kind of squishy because bubbles
of gas are trapped inside while it's being made.
But red plastic cups, which are hard, are made of
the same plastic but processed differently.
Plastics can be soft or hard. They can
be strong and hard to break or weak and crack
easily. They can be light weight or really
heavy. They can bend and stretch or they can
be stiff. They can melt when heated or be
strong even at high heat. There are many types
of plastics and so keeping the facts straight
about plastics might be hard, but one good thing
to know is that the large variety of plastics is
due the ability of scientists and engineers to
control the properties while making the
material. | 
