Video narration
When you stand in the morning sun, why does your skin feel warm while the surrounding air does not heat up the same way? Think of a dark T-shirt. Sunlight reaches the shirt and the air, but reaching something is not the same as absorbing it. The shirt absorbs much of the radiation at its surface, so it warms. Dry air lets much of that sunlight pass through, so it heats far less directly. That is the key flip: receiving sunlight is not the same as absorbing sunlight. The terminology needs care. Diathermanous means transmitting radiant heat with little absorption. Athermanous means absorbing or blocking it. Skin and clothing behave this way for much of incoming sunlight. Air is not non-absorbing. It absorbs some wavelengths and can warm from the ground. Why feel warm? Your skin or dark shirt absorbs sunlight, while dry air mostly lets it through.