Blowing warm air from the lungs onto a hot potato can cool it faster than natural cooling in still air. When left to cool naturally, the potato heats the surrounding air, which rises and creates convection currents, but blowing air replaces this warm air with cooler air more efficiently. Additionally, blowing through a narrow opening can cause the air to cool below room temperature due to rapid pressure changes. A practical demonstration shows that blowing with a narrow opening cools the skin more effectively than blowing with a wide mouth. This illustrates the principles of convection and the effects of airflow on heat transfer.