Questions with the keyword 'sound'

• what if helium makes our voices normal and oxygen makes them deeper? by icey666 to Hitesh, Hywel, Mae, Nik, Tiffany Comments: (No comments so far )
• why does popcorn pop?x by alysha to Hitesh, Hywel, Mae, Nik, Tiffany Comments: (So far, one comment )