 Wind is air moving from a high pressure area to a low pressure area. Let's say that you blow up a balloon and pinch the end close with your fingers or um your teeth. When you open the balloon a bit air flows out but not in. Why? Air comes out because the pressure inside is higher than the pressure outside. Air pressure varies across different locations across the globe. Areas with more pressure have tightly packed air molecules. Low pressure areas have more spread out molecules. Air flows from the high pressure area into the low pressure area when there's more space for the molecules. That whoosh of air you hear and feel is wind.