Final answer:
Chip bags inflate at higher altitudes mainly due to decreased atmospheric pressure. The pressure inside the bag remains constant, but as the external pressure decreases with altitude, the differential leads to the bag inflating.
Step-by-step explanation:
Chip bags inflate at higher altitudes due to decreased atmospheric pressure. As you ascend to higher altitudes, the air pressure around you decreases. Since the air pressure inside the chip bag was sealed at a lower altitude where the air pressure was higher, the difference in pressure causes the bag to inflate as you go higher. This is a straightforward example of how changing atmospheric conditions can impact everyday objects.
Variation of air pressure with altitude is a key concept in understanding this phenomenon. At sea level, the atmospheric pressure is higher and it decreases as the altitude increases. This also affects the oxygen levels and can cause altitude sickness for people who are not acclimatized to higher altitudes, because the body has to work harder to take in oxygen.