Answer :
Final answer:
Cork has a zero Poisson's ratio due to its unique cellular structure that does not expand laterally when compressed. Other materials sharing this characteristic are known as auxetic materials, such as certain polymers, foams, carbon nanotubes, and graphene, and are usually engineered at the micro or nano-scale.
Explanation:
The special feature about cork that gives it a zero Poisson's ratio is its structure which allows it to compress without expanding laterally.
This trait is unique because typical solids have non-zero Poisson's ratios, indicating that they do expand or contract laterally when compressed or extended. Cork comes from the bark of the cork oak tree (Quercus suber) and is composed of cellular structures that are particularly good at trapping air, making the material lightweight and compressible.
Other Materials with Zero Poisson's Ratio
Other materials, often known as auxetic materials, share this characteristic with cork. Auxetic materials have a negative Poisson's ratio and become thicker perpendicular to the applied force when stretched.
Examples include certain polymers, foams, and even some high-tech materials like carbon nanotubes and graphene. However, these materials are often engineered or structured at the nano or micro-scale to achieve their unusual mechanical properties.
