Vinegar is a weak acid. It's much stronger than acid rain, but it can be used to show the effects of acid rain over time.
One effect acid rain has is on baby birds.
Soak an egg in vinegar during the course of the school day, or overnight.
You will find that the shell dissolves in the vinegar.
While acid rain is not strong enough nor does it act over a long enough time to completely destroy the shell, it does weaken it. This allows pollutants to potentially enter the egg, as well as reducing the baby bird's protection.