I began by placing the box that read "live specimens" on the table, then having students write the focus question, "How can you observe crayfish safely?" in their science notebook. It would have been much easier to wait until they all left, and set everything up after school, but it would have been like giving them a gift and saying "I unwrapped it and tried it out for you." It was important to me that they see the whole process. I asked them what expectations we should agree to so that everyone could be safe. My class came up with:
Several of my students had read about crayfish already in anticipation of their arrival, which contributed to a more informed discussion.
Next, I drew a T-chart on the board, labeled it structures and functions, and numbered it to three on both sides. I explained their job was to observe and record three of each. This provided just a little bit of structure to their first day exploring the crayfish.
I had everyone put computers away, and clear off desktops. When each table was ready, I brought them tubs with several crayfish of different size in each. I provided craft sticks to help with handling them, but we all found out pretty quickly that these crayfish were too small to get their pincers on us, so we abandoned them in future experiments.
After the crayfish were returned, water mopped up, and hands washed, I asked my students to write down a question they have about crayfish that they hope to find the answer to. I often use this as my closure because when I collect their notebooks, it lets me see where their curiosities lie, and potentially if there are ideas that I thought I taught that didn't get through.