To introduce measurement in my 2nd grade classroom, I usually use the book, "How Big is a Foot?" by Rolf Myller. The kids always get a kick out of the story, so this year I decided to take my introduction one step further. We pretty much acted out the concept in the book, but before I read them the story.
Multiple sizes of shoes (Barbie shoe, baby shoe, toddler shoe, 2nd grader shoe, woman's shoe, and a large man's shoe)
Butcher/Bulletin Board Paper
I put students into 6 groups (or however many shoes you have, I had 6 shoes). I told the students that I needed them to make me a bed today that was 6 feet long and 3 feet wide. They kind of looked at me funny, but I told them I just needed them to draw me a bed that was 6 feet by 3 feet. I tried not to give them too much information to start, but I told them that I'd give them a foot to use to help them measure out the bed.
Once the students were all in their groups around the room with their butcher paper, pencils, and markers. I started walking around and handing out shoes to each group and telling them that was their "foot" that they needed to use to measure their bed with. Not every group paid attention to the other groups, but they were more interested in the shoe that I had given them. They all worked diligently on creating their 6 foot by 4 foot beds. Some needed assistance with measuring it 6 feet long and then 4 feet wide. Since it was all an introduction, they hadn't experienced much with measuring in the past. It was a good pre-assessment for me just to see if they knew how to line up nonstandard units and measure with them. It helped me know where we should get started.
Next, we read Rolf Myller's book, "How Big is a Foot?", which has a king asking to have a bed (which hadn't been invented yet) for the queen for her birthday. When asked how big to make it, he used his own foot to measure out 6 foot by 3 foot, but this became a problem when the person building the bed had much smaller feet than the king.
After the story, we talked about our own beds that we created and why we can't just use whatever "foot" we can find, but we should have a STANDARD unit of measurement. Then, I introduced the unit of measurement: one foot and showed the students that it was equal to 12 inches.
The kids had a blast and I did, too!