Here's a classic science demonstration that is sure to grab your students' attention... and the people down the hallway... and every dog in the neighborhood! When your fingers are slid repeatedly along this 60-cm-long metal rod, an ear-piercing sound is generated. You control how loud the sound gets from a whisper to a auditorium-filling shriek. Absolutely incredible! This is a great experiment to demonstrate the difference between longitudinal and transverse waves (also see our Wave Modeling Spring #SPR-1). Each singing rod comes with instructions and a bag of crushed rosin to lightly coat your fingertips.