The sizes of a bubble trapped in solid after nucleation on the solidification front during an upward freezing of water containing a dissolved oxygen or carbon dioxide gas are experimentally measured and quantitatively predicted in this work. From an in situ measurements of bubble shapes in solid at cold temperatures of -25 and -15 C, it quantitatively shows that pore formation can be divided into five regimes: (1) nucleation on the solidification front, (2) spherical growth, (3) solidification rate-controlled elongation, (4) disappearance of the bubbles, and (5) formation of the pores in solid. To interpret experimental results, equations incorporated with the growth rate of a spherical bubble and solidification rate to predict bubble shapes in the solid during the spherical growth and solidification rate-controlled elongation are successfully proposed. Experimental data show the effects of initial gas concentration and solidification rate on geometries of the bubble in solid.