# Example of 1-D Poisson Equation in physics field, engineering field, or others in daily life

In 2D Poisson Equation I have example in electrostatics, $${\Delta ^2}\phi = - \frac{{{\rho _{el}}}}{\varepsilon }.$$ And I need an example of 1D Poisson Equation in daily life. In Engineering field, Physics field, etc. I will try to use a numerical method in that example. Can you help me please?