When I was planning for the Letter Y, I thought of Yardsticks and figured we could have a day on Measurement. I went to a local discount store and picked up some really cheap yardsticks. I envisioned the kids really getting into measurement and walking around seeing how tall and how long things were. Naturally, I planned an activity that was more involved and that required a lot of one on one teacher help.
Earlier in the day I cut out cardboard Rulers and made marks for the inches. This was good practice for the kids to write their numbers. I learned the hard way to write the letter 0 first, otherwise the kids started at 1 which throws off all the measurements.
This was in introduction activity, to teach the kids what it means and how to use it. The real application is when you set out and leave the materials frequently so the kids can explore and discover how to use them on their own. We have a tool set the kids absolutely love, so these materials will be set out so they have more time to grasp the concept. (The cardboard rulers went home, I have more at home the kids can use. I always pick up a few when the back to school sales are going on)