What is Kahoot?

Kahoot is a free online service for teachers to develop quizzes, surveys and educational games for their students, who can reach the quizzes through any device with a search engine.  The service is intended primarily for schools, but can also be used by colleges and businesses.

Students do not need an account for Kahoot, only the teacher needs to register. Your Kahoot questions can include pictures and videos. The teacher can impose time limits on their quiz, for which the student is awarded points for correct answers and the timeliness of their answers. The teacher can monitor the student's response using their on-screen scoreboard. Teachers can share quizzes between themselves and add YouTube films to their surveys.

The Whole Class Can Join In

As long as every student has an appropriate device (laptop, iPad, iPhone, iPod, Android, Chromebook, Windows Phone, PC, etc.) the class can compete against each other for top places, by use of a projector device, and some sort of screen positioned at the front of the classroom. The teacher can then monitor the class's progress as a whole and offer help and advice at the same time to individuals. 

Here's a tutorial to show you how it's done: