Tuning forks are fascinating, simple tools that don’t get quite enough appreciation. Striking a prong against a hard surface causes the fork to hum in a specific pure frequency. This frequency is calibrated based on the fork material and size....

Stethoscope enamel pin available in gold and silver The stethoscope is an acoustic medical device for auscultation, or listening to internal sounds of an animal or human body. It typically has a small disc-shaped resonator that is placed against the...