Final answer:
The warmth of your breath when you blow on your hand and pucker your lips is explained by the transfer of energy and increased movement of air molecules.
Step-by-step explanation:
The subject of this question is Physics. When you blow on your hand with your open mouth, you feel the warmth of your breath. This is because when you blow, you transfer energy in the form of heat to the surrounding air, making it warmer. When you pucker your lips so your breath expands as you blow, the air molecules are forced to move faster, resulting in a greater transfer of energy and a warmer breath.