Investigating Energy Transfer Using Music and Lasers
- Grades: 3–5
One of the coolest experiments to conduct when teaching energy transfer is one that uses various music genres and a laser pointer. It’s a fairly simple experiment to set up and it leaves a lasting impression on students.
By bouncing the laser beam from a laser pointer off an elastic surface, students can not only “see” that sound is vibration, but work through/reinforce the scientific thought process as well. Here is a list of what you will need to set and run the experiment:
1. CD player
2. tall tin can (with both ends removed)
3. large balloon
4. laser pointer
5. duct tape or Velcro
6. CD with various genres of music
7. small mirror
After removing both ends of the can with a can opener, cut a circular piece of the balloon and stretch it over one end of the can and tape the edges to the outside of the can. The surface should be taut. Next, take the small mirror and attach it to the piece of balloon that you attached to the can. Tape or Velcro the can (open end facing the speaker) to one of the speakers on the CD player, it’s perfectly fine that the opening of the can doesn’t cover the entire speaker. I set the CD player on a stool or desk in front of my white board and finally attach the laser pointer to the tray on my white board so the beam of light is pointed at the mirror on the can which causes the beam of red light to be reflected back onto the white board.
Before we begin the experiment, the class and I discuss all of the energy transfers that will take place once we begin this experiment. This is also a great opportunity to reinforce the Law of Conservation of Energy. I have the students hypothesize which genre of music will cause the most vibrations (or will move the light the most). They record their hypotheses and it generally leads to more discussion on the genres I chose. Students then rank the genres in terms of which they think will cause the most vibration. After playing each song and observing vibrations, conclusions are discussed and hypotheses reconsidered. While simple, this experiment is one that my students love because it is so powerful for them to actually visualize the vibration of the music.
All the best-