I had a blast with 5th graders the other day who were investigating PITCH in their SOUND unit. Students explored and researched the different pitch levels and why they occur.
One small group decided to make a water piano/xylophone out of glasses, water and a MaKey-MaKey. We programmed different pitches to sound in Scratch when the water in each glass was tapped. Each glass contained a different amount of liquid.
As you can see in the video at the beginning of this post, the students had a blast figuring out which glass of water would have the highest pitch (the one with the least amount of water) and which glass had the lowest pitch (the glass with the most water). When the glasses are full, the vibrations have more water to travel through. This slows down the vibrations and creates a lower pitch. There was a lot of critical thinking and problem solving involved and I KNOW these students will never forget this concept. I know I won't!