Why does soda pop go flat at high altitude?

Soda pop goes flat at high altitude because the atmospheric pressure is lower. This allows the carbon dioxide gas to escape from the soda more easily, making it go flat.

The amount of carbon dioxide that can be dissolved in a liquid is proportional to the pressure of the gas above the liquid. When the pressure decreases, the amount of carbon dioxide that can be dissolved also decreases, causing the gas to escape from the liquid.

Altitude affects the pressure of the atmosphere. The higher the altitude, the lower the pressure. This is because there is less air above the liquid at higher altitudes, so the weight of the air pressing down on the liquid is less.

The lower pressure at higher altitudes allows the carbon dioxide gas to escape from the soda more easily, making it go flat.