I don't know about you, but "punctuation" and "inquiry" never sat well together in my mind. It's was not something I particularly enjoyed teaching because there were all these rules and endless worksheets which all seemed to be a HUGE bore.  
Then Steve Peha came to my rescue...yet again. On his awesome website there is a great document called "Conventional Wisdom".  He showed the way to do a punctuation inquiry which adapted very well for my Grade 2 class. I found it to be very student centred and they turned out to have a pretty keen eye on how punctuation and other convention rules are used. Below is Steve Peha's example...I will share how I used it. 

Then, I read them a story. I chose Little Beauty by Anthony Browne because it was a sweet, simple story that had the punctuation we were looking for. I didn't want the students to work too hard understanding the story, I wanted their focus on punctuation! 

After I finished reading the story, I took example sentences and showed the students how to complete our punctuation charts. I talked about JACKPOT sentences, ones that had all the examples of the conventions we were looking for. Those sentences could be written more than once on each chart.  Basically, the students were given these instructions:

Search in books for sentences that have the punctuation we are looking at.

Choose one sentence and copy it on the relevant chart. 

Underline the punctuation. 

Look for JACKPOT sentences, you can use that one sentence on ALL the charts! 

Here are the students completing their charts. 

Once we started wrapping things up...I kept thinking, now what? I thought things went very well but it didn't seemed quite finished. How could I get the children to think about all of this in the context of their own writing? 

I thought if students completed a Learning Journal, where they applied the rules to their own writing, things would seem more buttoned up in our little inquiry. In the first column of the Learning Journal, they had to copy the rules they had come up with from the chart. Then, they had to search for examples of these rules in their own writing. 

This worked out well because they noticed places where they had not included punctuation or capitals...places where they really should have. They were allowed to revise their sentences in the Learning Journal

First,  I had the students brainstorm conventions they see in book they read. They came up with a list:

- periods, exclamation points and question marks (I kept them together since they are at the ends of sentences)
-capital letters
-apostrophes
-speech marks

While the students went out for snack, I whipped together these charts....a la Peha!

Once we filled in the first columns of our punctuation charts, we looked at each sentence on each chart.
For each sentence, we did a Think-Pair-Share where students discussed why they thought that punctuation was there. We called these "convention meetings". Once they had agreed on why, I recorded it on the chart in the WHY column.
 
This took a LONG time. We did one chart a day until we were finished. The class got better at it as we went along. As you can see on the right, they were very insightful. I was especially surprised with their ideas on commas. 

After, we shared questions we had. There were not too many questions but I think we will see more questions as the students become more aware of punctuation in their reading and writing. 

My class and I have been enjoying the mini-inquiry so we thought we'd tackle learning more about adjectives in the same way rather than using worksheets. It also provided the opportunity to use prior knowledge and our own work as a legitimate research source and in an authentic way.