Abstract: In daily life, adding salt to the colloidal protein solution will cause aggregation. Based on the spherical colloidal particle model, this article uses the Poisson equation of electrostatics and Boltzmann's law of distribution to discuss the aggregation of protein molecules. By digging out physical thoughts in daily phenomena, not only deepen the understanding of the laws of physics, cultivate the ability to solve practical problems, but also enhance the effectiveness of teaching. 

Key words: charge distribution, colloidal particles, electric potential, permittivity, shielding effect