I missed the part where you said this was to explain it to thirteen year olds.
I reckon if that's your goal, then you might ask what is epistemology
for? Well, it's the study of knowledge, right? :)
What does that mean? At a basic level, epistemology should deal with
questions like Can we know anything? What can we know? And how can we
know what we know is true or free of error or at least in the
ballpark? Then it can get more particular to ask where does knowledge
come from. (Reading the classics? Great authorities like the sages or
prophets? Personal experience? Innate ideas? Whatever works? Etc.)
And then we can ask what form knowledge takes overall. (Is it like
just a heap of unconnected factoids? Or is it more like a building
with foundational stuff on which all other knowledge rests and there's
a hierarchy -- maybe running from logic to math to physics to biology,
etc.? Or is it like a web where changing one part might affect other
parts in subtle ways?) And then one can ask about stuff like logic,
science, math, the role of emotions, rhetoric, etc.
Think of the above as the What's it for? approach to any topic. I feel
it works well for many fields -- not just epistemology. In fact, David
Saum many years ago applied it to concepts in general. If someone has
a concept -- which can be anything from the concept of dog or the
concept of green to the concept of individual rights or of the
scientific method -- then you ask What facts gave rise to this
concept? Of course, this doesn't limit one to concepts related to
brute physical facts. One can ask it about mathematical concepts,
literary criticism, film genres, the idea of god (even if one is an
atheist, one can ask what gave rise to the concept and whether there's
some unified concept there), unicorns.. You can go wild. :)
By the way,elsewhere you mentioned a quote often attributed to
Einstein about being able to explain something to a six year old or
something along those lines. In fact, he never said that. Something
like that is often attributed to Feynman too and to someone else. By
the way, there's a quote from Feynman that makes it seem like he might
not have said it:
“Hell, if I could explain [quantum electrodynamics] to the average
person, it wouldn’t have been worth the Nobel prize...” :)
See:
https://www.latimes.com/archives/la-xpm-1988-02-16-mn-42968-story.html
Not sure if he really said it, but the LA Times seems somewhat credible.
Regards,
Dan