A card selected by the spectator is lost in the deck and the deck is shuffled. By riffling the cards only one card pops out, but it happens not to be the selected card. By tossing the card into the air it visually shrinks and changes into the spectator's card.
By leaving the card on top of the table and placing the hand on top the card grows once again!
A very visual magic trick!
Very easy to do!