What is why do car windows get foggy when making out?

Car windows often get foggy during activities like making out due to the increased moisture and temperature inside the vehicle. Here's a breakdown of the factors that contribute to this phenomenon:

1. Breath Condensation: When people breathe, they exhale warm, moist air. In the confined space of a car, this moisture accumulates quickly.

2. Temperature Difference: The temperature inside the car is often warmer than the outside, especially when people are present and moving around. This temperature difference causes the warm, moist air to condense on the cooler surfaces of the car windows.

3. Limited Ventilation: Cars with the windows rolled up provide limited ventilation, trapping the humid air inside. Without proper airflow, the humidity level rises, leading to more condensation.

4. Heat Transfer: The glass windows transfer heat differently compared to other surfaces, cooling faster and thus reaching the dew point quicker. This makes the windows the first place where condensation becomes visible.

5. Environmental Conditions: Weather conditions, such as cold or rainy weather, can exacerbate fogging. Cold air outside makes the windows cool down more rapidly, contributing to faster condensation from the warm interior air.

To mitigate window fogging, you can use methods like turning on the defroster, opening a window slightly for better air circulation, or using the air conditioning system to remove humidity from the air.