Flexibility

Unlike rubber bands, paper clips and plastic straws cannot be stretched. However, they can be bent, turned, or twisted because they have the special property called flexibility, or the ability of a material to bend without breaking.

Hardness

If you have seen pictures of a car that had rammed against a concrete wall, you must have noticed how the car ended up squashed and a total wreck! This is because the wall was too hard for the car’s impact. Hardness is the special property of matter that allows it to resist being scratched and dented. In the case of the wall, it may have been scratched or smashed in some parts but because of the hardness of the concrete, it was able to resist the impact of the car’s crash. The wall may have sustained damage but only less than the damage on the car.

Almost all metals exhibit hardness. However, the hardest solid that is known to people is the diamond, which is not a metal.