麻豆约拍

Mark Miodownik tests the strength of a concrete beam by walking along it. He discovers that the concrete is not able to tolerate the bending effect his weight is having on it. Compression is seen in the top surface of the beam, and tension is seen in the bottom of the beam, which causes it to fracture.

An animation is used to explain that tiny pores in the concrete expand when stretched, causing cracks to appear and grow.