In this article we will study sound—specifically, how sound allows us to communicate in a classroom and can improve that communication. You learn is measured people called acoustics engineers help architects designers make sure classrooms are not too noisy—or quiet. We even have some experiments you do measure sounds at home, school, or football stadium.

Maintaining traceability for transfer standards in the range of 10 Pa to 5 kPa is critical to many calibration laboratories. However, standards with suitable uncertainty that can also be practically implemented in the typical laboratory have not been available. A new pressure standard based on piston-cylinder technology has been developed that provides the measurement uncertainty needed to supp...