An extremely easy student response website that works from any iPad, computer, chromebook or cell phone with internet.
Sign up at socrative.com for free and be ready to get student responses in minutes. Only the teacher needs a Socrative account, students simply go to the website m.socrative.com and enter in the 'room number' that the teacher gets with their account.
Students go to the website, enter in a five digit number that has been assigned to that teacher, and can respond in real-time to questions asked in class. Feedback is instant on the teacher side.
*Note: Socrative has iOS Apps for both Students and Teachers, but the website socrative.com seems to work the same without Apps.