After students watch the video and before practicing, come together for a whole-class discussion. Use student answers to the questions provided as the basis for discussion. Student observations may include:

• Two separate projects must be made for the robots to message each other.
• The projects have to be started on each robot, and Robot R's (receiving) project is started first so it is ready to receive the message that Robot S (sending) sends when it's project is started.
• The words in the send message block align with the words in the contains block.

Review expectations for group work to begin. Briefly remind students of their roles to ensure they are set up for success.

In this guided practice, students will investigate how the way in which the sending robot's message affects the receiving robot's behavior. They will form hypotheses about the message’s outcome, then modify Robot S’s (sending) code before downloading and running both projects to test their hypothesis and record the results. Students should discuss how the receiving robot behaves with each message sent, using the suggested questions on the task card.

Distribute the Step 3 task card  (Google / .docx / .pdf). As students are modifying the project to test each message, circulate around the room and engage students in discussion about their progress and understandings. Ask questions like:

• Which message are you sending? What's different between this message and the message in the original project? What is the receiving robot's response?
• What patterns do you see in your results as you test the different messages? Why do you think that is?
• What is the most challenging part of this task for you? How is your group working together to solve that problem?
• How do you think clear and careful communication can help you create successful projects using messaging between robots?
• What other questions do you have about coding your robot to send and receive messages?

Guide students to share their learning in a whole-class discussion. Help students reflect on their learning through practice to converge on shared understandings or learning targets. 

Use the questions students answered in their journals as the starting point for the discussion. Ask follow up questions to guide student understanding: 

• What is something you know now about how to code robots to sending and receive messages that you didn't know previously?
• Was there something you tried that did not work as you thought it would? What did you learn from that practice?
• How did you communicate between two groups during guided practice? What did you learn from that communication that can help you moving forward throughout this unit?

Note students' shared understandings about sending messages to refer back to as they progress through the unit. This way, students can see how their understandings grew from the start of the unit to the end of the challenge, as they explore concepts and understandings related to the essential question.