It may be a bit lofty of a goal to try to teach the theory of major and minor chords or modes to preschool students. So I don't try to do that. However, young children CAN learn the difference between major and minor chords by how the sound makes them feel! We all know by now that these young minds and hearts have all the feels, right? They know when they feel sad, happy, scared, or excited, and we can use what they know to help them understand the concept of major vs minor in music. I start by explaining the terms as simply as I can. I use the classic "happy face/Sad face" symbol, picture an emoji. The happy face says Major on it and the Sad face says Minor on it. Most of the children I teach can't read yet, but they sure know what the happy and sad face represents. Every time I hold up the happy face, I say "major" and sad face, "minor". We do this several times so they begin to associate the icons with those terms.
My piano doesn't get used much in the class as I play most of our sing along songs on the ukulele, but I find this lesson works well with a keyboard. I play them a major chord, and let them know it's a major chord. We all recognize that it sounds pretty "happy" then I alter the third in the chord to make it minor. Now it sounds a bit sad. I play several chords like this as we practice listening and making the distinction. I find that it's super helpful to take a song we know and love, "You are My Sunshine" and play it once through normally, with all major chords. Then I play the same song with all minor chords. So tragic I tell ya! The children immediately notice how sad that familiar song can become when we change the chords to minor!
Throughout the rest of the month we do activities that promote listening and expression. Week two we colored on a sheet that was split in half: happy face/sad face. The children listened to a medley of different pieces of music. They chose to color on whichever side that corresponded with how the children felt when they heard it. Then we incorporated a bit of drama when we used our face and body to depict how the music was making us feel. It's fun and keeps them engaged!
We finished up the month with a guest musician on the mandolin. Our guest even talked a bit about major and minor and the children were able to pick out which songs were major and which were minor! They had a blast learning about and listening to the mandolin