[bai-giai-den-roi-cham-com]-Luyen-doc-reading-voi-bo-giao-trinh-oxford-level-5

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Materials have different properties, like being
strong or transparent. Composite materials are
made by weaving, using molds, or fixing two
materials together. They have the best properties
of both materials. Composite materials are very
light and very strong, so we use them to make
things like fishing rods, tennis rackets, and planes.
Some composite materials are made of plastic, glass,
or metal fibers. You can weave them into special
clothes. Some of these clothes are stronger than
steel. They protect police officers from people with
weapons, and they protect firefighters from fires.
Aer gel
Aerogels are made from chemicals like silica and
carbon. Silica aerogel is the lightest material in the
world. It's difficult to see because it's 99.8% air! Hot
and cold don't go through aerogel, so people use it to
insulate things like windows, machines, and special
clothes for astronauts.
atf' .
It's bad for our world to throwaway too many things.
This uses energy and materials, and produces waste.
It's good to recycle as much waste as possible. Then
in factories, people can make new materials from
these recycled materials. We use new materials made
from recycled plastic inside cars because these
materials are light and strong.
Go to pages 46-47 for activities.