Here's why:

* Composition: Plasticine is primarily made from a mixture of oil, wax, and a filler like clay or flour. These materials are not good conductors of electricity.

* Electrons: Conductors allow electrons to flow freely through them. Insulators resist the flow of electrons. Plasticine's molecular structure hinders the movement of electrons.

In summary: Plasticine is an insulator, meaning it does not allow electricity to flow through it easily.