Google Slides Q&A. This is a hidden gem that you might not have seen before!
Tricider. No login is necessary, even for the teacher, but you'll want to log in with Google when you create new Triciders so you can see your history and edit your questions if necessary. Students never need to create an account.
Mentimeter. In the free version, you can have 2 questions and 5 quiz questions per topic, with an unlimited number of participants. There are different question types, which makes this tool a little different from the two above. Sign in with Google so you won't have to remember another password.
Remember that using a backchannel is a great way to mentor your students in great digital citizenship - but you have to set them up for success by talking about your rules and expectations ahead of time! Getting your students to come up with the rules and norms for class discussions, as well as consequences for infractions, will likely head off some of the negative behavior. If you need additional suggestions on using backchannels successfully in your classroom, contact any member of your Digital Learning team - Clara, Leah, Fern, or Nancy!