Opening a bag of potato chips only to find that it is only half full will leave you downcast, slightly frustrated and with unanswered questions about the reasons for it. If this describes you, then you should know that manufacturers like Lays and Tostitos do this in the best interest of their customers.

This empty space is called a “slack fill” and it is placed around a product for a specific purpose — protection. The extra room is expected to work as a buffer that protects the potato chips from external impact that may compromise their appearance and quality.

If it weren’t for a slack fill, potato chips would most likely arrive at the supermarket in crumbles!

But that isn't the only function of a slack fill. According to experts, the slack fill isn't just air, it is specifically nitrogen gas. While ordinary air would leave the chips soggy and spoiled after some time, the nitrogen gas acts as a preservative that keeps the chips fresh.

This practice is backed by a 1994 discovery that exposing chips to nitrogen can extend the shelf life, and also make them taste better.

Don't worry, nitrogen is absolutely harmless!

Tip: If you still want to know just how much is in your potato chip bags, check the net weight that’s printed on the bag. This will help you determine if the bag is really worth buying.

Don't forget to enjoy the chips!