"I'd like to teach the world to sing, in perfect harmony ..." (thirsty now?)
The longer I teach, the better my students are singing. This is a sentiment that (hopefully) all music teachers find. I think the quality has really improved at the elementary level since I started teaching a section of middle school choir three years ago. My expectations are higher for my elementary students now, and the students live up to them beautifully.
I have a set of ten songs for 5th grade, many of which include singing in harmony. We do warmups in harmony just like a choir would. At this early stage of the year, we have one warmup and three songs being sung in harmony. The three songs are Peace Round (Share the Music), Erie Canal (Music Express), and Yellow Bird (Share the Music).
But we cannot just teach our kids to sing in harmony. Teach your kids about the different types of harmony. These three pieces form harmony in three different ways:
Peace Round - canon
Erie Canal - melody plus descant
Yellow Bird - homophonic (although we just call it "true harmony" right now)
After learning all three of these pieces, I asked the students the question "How do you make harmony?" I was quite pleased and impressed with their answers. Together, they were able to define these three different forms of harmony.
I think of this like reform math - it is not enough to just be able to do the math problem; you need to know why it works. Same thing for music - teach students to explain their musical thinking and we will build better musicians.