To feel or see the difference between aspirated and unaspirated sounds, one can put a hand or a lit candle in front of one's mouth, and say pin [pʰɪn] and then spin [spɪn]. One should either feel a puff of air or see a flicker of the candle flame with pin that one does not get with spin. In most dialects of English, the initial consonant is aspirated in pin and unaspirated in spin.
Try to answer this question if possible (otherwise reply "unanswerable"): What would you do to see the similarities between aspirated and unaspirated sounds?
unanswerable