Introduction Relationship between reading and lecture The lecturer talks about the natural process of crystallization and how the speed of cooling can influence such process，which is proved by Bowen’s crystallization experiment explained in the reading passage． Points in the lecture Natural crystallization happens when magma，which is extremely hot in its molten form deep in the earth．gradually cools off when it moves towards the surface of the earth．During the cooling process，the energy from heat is lost，and the atoms which compose the magma begin to move more slowly, forming into an orderly pattern，which turns the magma into a solid crystal structure．Howeve if the cooling process takes place too rapidly, then there is not enough time for the atoms to be arranged into such an orderly pat tem．Therefore，crystallization can’t take place．Instead，a brittle，glass-like material will form． Points in the Reading Norman Bowen’s experiment in the 1 920s proved this theory．By collecting and melting elements in rocks，Norman created artificial magma in his laboratory．He first cooled the magma slowly, as in the natural crystallization process，and got mineral crystals． But then he suddenly replaced this normal cooling with rapid freezing，and found frozen glass materials surrounding the solid crystal structure．
