Asked by: Tracy Stott, Selby
We smell gases because their molecules are free to enter our noses. We smell liquids because some of their molecules enter the gas phase after escaping from the liquid surface. Solids can also release molecules to the gas phase, albeit slowly, but the usual reasons why we can smell them are that they contain volatile oils (such as most woods), or that they are chemically reacting with something from the atmosphere to produce a gas.
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