3. You can take a breath of Helium to change the sound of your voice and demonstrate how density affects the spread of sound. As you talk or sing after breathing in Helium, your vocal cords vibrate and the sound waves are produced through helium instead of air. Your vocal cords simply vibrate differently in the lighter gas. Helium sound waves are actually 6 times lighter and denser than regular oxygen (this is why balloons float); therefore, they travel much faster than air during the short period of time that it takes for them to make their way out of the throat and mouth. The pitch of our voice doesn’t change when breathing in helium, but the quality of our voice does. The quick-moving higher frequency sounds have more power as they float in your throat, and the lower frequencies tend to get lost, causing the voice to sound flat. Helium Atom

5. Materials needed: One or two balloons A person to breathe the Helium A pair of scissors to slit a hole in the bottom of the balloon Procedures: 1.Obtain the balloon full of Helium and cut a small slit in the bottom of the balloon where the plastic is the skinniest. 2.Hold the balloon closed with your hand until you are ready to breath the Helium so that no Helium escapes. 3.Let as much air out of your body as you can and breathe in Helium. The first time, breathe a quick, small amount of Helium, talk, and record what your voice sounds like. The second time, take a full, slow breath of Helium and record your results.

6. Small Amount of Helium Full Amount of Helium I noticed a smooth, but noticeable change. My voice simply sounded like a lower-pitched chipmunk. My voice changed dramatically. The sound was smooth and tone of voice was changing every second. Independent Variable: Amount of Helium breathed in. Dependent Variable: The change in my voice. Control: Helium. (Analysis)

8. In this experiment, I used Helium to show the difference in density, in comparison with regular oxygen that we breathe on a daily basis. I changed the amount of Helium that would get breathed in each time, and realized that the amount of Helium I attempted to breathe in also determined how quickly I would breathe it in as well. The second thing I noticed was that I felt a slight tickle in my throat when breathing in the Helium and talking when I was exhaling. This probably occurred because of the myth that Helium vibrates your spinal cords differently, and possibly quicker than oxygen does. The Helium’s light density made it want to float right out of my throat, which is also why the Helium didn’t want to keep my voice changed for a long period of time. The changed voice lasted about 5-10 seconds. In conclusion, I think that this experiment was both fun and educational, which was mainly because of previous research and physical tests.

9. http://chemistry.about.com/od/chemistryactiviti es/a/Helium-Voice.html http://chemistry.about.com/od/chemistryactiviti es/a/Helium-Voice.html http://ilovebacteria.com/helium.html