"Every human being is a field of energy. Energy doesn’t simply flow through us — we are energy. This was discovered by humanity’s earliest natural scientists— the ancient Chinese physicians who studied the mysteries of the human body and mind. It has also been discovered by the modern scientists who reveal the wonders of our subatomic existence." ~Master Kam Chuen Lam ..*
A Pan Flute. Shorter pipes produce higher frequency sound waves and a higher pitch. Good activity when you teach a unit on sound. The link gives you exact measurements to make notes in a true scale so you can play songs. The shortest straw must be exactly half the length of the longest straw.