Walk into Choral Clinic when Van is at 3 or more hearts.
Inside the clinic, Van is explaining how evaporation occurs and creates rain. Your child listens and understands that the water from the pond is not completely lost since it falls back down. Van doesn't know what he/she means when your child talks about the pond on your farm, so your child asks if he knows that ponds are the starting point for a river. Van didn't know that you had a pond that started a river, and wants to check it out.