I think it is important to establish a safe space in the classroom first. Set some ground rules for group work and discussions.
Then I would have students respond individually probably in writing. Then they would have time to share at their tables, but each student would be asked to share. They would then create a list either on chart paper, post-it notes, or index cards to display for the class. We would then get into the discussion of what makes something a computer. I think it best again to do a think, pair/group, share. Give each student a chance to think it through themselves before working with others to come to consensus of sorts.