# Why $E$ for conducting plate is twice that of non-conducting sheet?

Why is electric field for same surface charge density(σ) is twice in case of a conducting plate or surface (σ/εο) than to a non-conducting sheet (σ/2ε)? One explanation I have found is is because "In the non-conducting surface the entire charge is distributed on both sides of the surface (thus 2 times the area), whereas in the conducting surface, the charge is distributed only on one side." Why is charge in this case distributed to only one side and why not both sides?