It seems that nitrous oxide (N2O) is frequently used to create whipped cream. But why can't just regular nitrogen gas (N2) be used instead?
To aerosolize the cream to make whipped cream requires the gas be able to be dissolved in the cream. Nitrogen just does not dissolve in cream that well. It could be done with O2. But that would cause it to spoil almost as soon as it was made. For these reasons Nitrous Oxide is used instead of just Nitrogen or Oxygen.