You’ve heard this safety warning every time we flew with a plane: “During emergency, oxygen masks will drop down in front of you”. It’s pretty straightforward, right? Oxygen masks. Masks filled with oxygen.
Well, that’s not exactly the case. Oxygen masks are not exactly filled with oxygen. At least at the beginning. Because having oxygen tanks on board would significantly increase an aircrafts’ weight, engineers have found a clever way to get you oxygen when you are 40,000 feet above ground. Oxygen masks make their own oxygen.
Filed with a set of chemicals (commonly sodium perchlorate and an iron oxide), when you pull down on the mask you are actually releasing the chemicals letting them mix together. This chemical reaction creates the oxygen that eventually flows to you! Because this is a chemical reaction, it’ll generate a burning smell. But don’t panic (easier said than done), it’s how it’s supposed to smell. (the article continues after the ad)
Oh, and because people often get weird by just listening the word “chemicals”, don’t worry, it’s perfectly safe to breathe.
Bonus fact: The oxygen in a typical mask only lasts for 15-20 minutes. According to the experts, this is usually plenty of time for the pilot to get the airplane to a safe altitude.