Includes index.

"When a bell rings or a buzzer goes off, it often serves as a reminder to complete a certain task or directs our attention to something that needs to be done. Readers learn about the various functions of bells and buzzers and how they operate throughout this detailed main text, which explores essential science curriculum topics. In addition, informative fact boxes, comprehensive diagrams, and eye-catching, full-color photographs encourage young learners to become interested in STEM concepts and develop a deeper appreciation for the science at work all around us"--Provided by publisher.