Triple point of water is a single point in P-T phase diagram of water where the three phases of water coexist. For practical applications people use the triple point cells. This video explains how to realize the triple point in this cell.
My question is:
To get to the triple point, temperature and Pressure should be set to specific values but what he shows in this video is just cooling the cell to make some ice! How is that enough to reach the triple point??