I've pinned it down!

I've already decided which science experiment i'm going to do!
I'm going to do the old acid and rusting topic! I'll go through the processes
that you need to go through later, but first i'll tell you a hint.
It's got something to do with nails/iron.....

I'll tell you what you need first:
3 iron stuff/nails
3 jars
1 lemon
1 ph scale
vinegar
tap water

Thats all I'll tell you for now............ and i'll tell you more later.