1. The problem statement, all variables and given/known data 1) When sound waves travel through increasing temperature, what increases, frequency, wavelength, or both? 2) When you inhale helium and then your voice becomes high and squeaky, what causes this to happen? 2. Relevant equations Vsnd= √(γRT/ M) vsnd= λf 3. The attempt at a solution I know that in both # 1 and 2, the speed of sound increases, but I'm fixated on the concept that when sound travels through different mediums, such as from air to water, the frequency stays the same, but the wavelength changes. For #1, Temperature increases, which increases the velocity of the molecules in air, so I'm assuming that the frequency increases as the number of oscillations/s increases. However, does the wavelength change? For #2, I'm confused on how frequency(pitch) changes, if the medium is changed. From the recent concept in that the frequency of sound does not change from one medium to another and that the speed of sound increases in He than in air, because He is less dense than air, how does your voice get higher as you inhale helium?