I’ve mentioned in the past about using Pushbullet to send links, text and other information to your students. Yesterday, Google announced the Google Tone. This adds a new icon in the toolbar that when pressed, emits a series of tones that other browsers with the extension installed will hear. I’ve tried it out at home, and it works ok for two laptops, but I assume it would work even better with speakers or the sound reinforcement in a classroom.