People have been making composites for many thousands of years. One early example is mud
bricks. Mud can be dried out into a brick shape to give a building material. It is strong if you try
to squash it (it has good compressive strength) but it breaks quite easily if you try to bend it (it has
poor tensile strength). Straw seems very strong if you try to stretch it, but you can crumple it up
easily. By mixing mud and straw together it is possible to make bricks that are resistant to both
squeezing and tearing and make excellent building blocks.
Another ancient composite is concrete. Concrete is a mix of aggregate (small stones or gravel),
cement and sand. It has good compressive strength (it resists squashing). In more recent times it
has been found that adding metal rods or wires to the concrete can increase its tensile (bending)
strength. Concrete containing such rods or wires is called reinforced concrete.