text: please describe why a closed car heats up in the afternoon sun.? i know that it has to do with conduction and convection.  i am looking for specifics.  the formula relating density, volume, etc... to the temperature in the car. the sun's radiant heat, heats the seats, etc.  the glass allows the radiation to penetrate into the car.  however, by convection, the air heats up in the car from the hot surfaces, and then the glass prevents the heat in the air from escaping.  this is a mini model of the "green house" effect.