It's only one motion. Pull a loop through another loop. (This requires yarn, but not needles.) Held in your lap with your hands over his, a toddler can do it. Sitting beside you, a six-year-old can do it herself with enough practice. A sixteen-year-old can learn it in five minutes. Right-handed people can teach it to left-handed people without trying to accommodate their different strengths. It's just a single motion.
But it's such a rich subject.
- You can go into how to tension the yarn: English, Continental, Portuguese, probably others I've never heard of.
- You can talk about the orientation of the stitches: Western, Eastern, and Combined; leading and receding legs, front and back loops.
- You can explore different types of knitting: colorwork, cables, lace; in the round or back and forth.
- You can talk about the needles: straight, circular, and double-pointed.
- You can go into the yarn: weight, texture, fiber content, twist (you can get so far into this subject you end up in spinning theory).
- You can learn about changing shapes: increases and decreases of all types.
- You can research expert tricks: reading your knitting, dropping stitches to repair errors, lifelines, frogging and picking up live stitches.