Okay kiddo, so have you ever rubbed a balloon against your hair and then stuck it to a wall? Remember how it stuck there by itself without falling? Well, that's kind of like what permittivity is all about.
You see, everything around us has tiny particles called atoms that have what's called an electric charge. Some atoms have more electrons, which are negatively charged particles, while others have more protons, which are positively charged particles.
When we talk about permittivity, we're talking about how easily something can store an electric charge. Think of it like a container that can hold water. Some containers are better at holding water than others, right? It's the same with electric charges.
The "relative" part of relative static permittivity just means that we're comparing how easily different materials can store electric charges. And the "static" part means that we're talking about electric charges that aren't moving around - they're just staying in one place.
So when we say "relative static permittivity," we're really asking how easily can different materials hold electric charges that aren't moving around. Some materials, like air, don't really hold electric charges very well, while others, like certain types of plastics, are really good at holding onto them.
And that's the basics of relative static permittivity - it's all about how materials hold onto electric charges that aren't going anywhere.