Bernie: "Dear Nina, that's right, sometimes the machine beeps when you go through the security check and sometimes it doesn't. Every passenger has to go through the security check before he/she is allowed to board the airplane. The beeping is a signal for the security personnel.

But not only the passengers are checked thoroughly, also their hand luggage - in other words the luggage that travels with the passengers in the cabin, instead of in the hold."

Lexi: "Do you actually know why everything is checked, Nina? There are certain items that are not allowed to be taken on board an airplane. For example, weapons such as knives, but also scissors, because they are sharp too.

One also checks that the passengers are not carrying any liquids with them. So, you should always finish off your drinks before arriving at the security check, otherwise you have to throw them away."

Bernie: "Precisely, Lexi! But to come back to the beeping. The hand luggage and items of clothing such as jackets, belts and scarves are placed in a box on the conveyor belt and pass through a crate-like machine where they are X-rayed.

This allows the men and women from the security staff to identify forbidden items easily. The passengers are also checked. To this end, they walk through a so-called metal detector, which looks like a door frame. The metal detector beeps if it detects anything metal.

If this happens, the security personnel check the passenger again using a handheld metal detector to see if he/she is wearing anything forbidden directly on their body. Sometimes one even has to take one's shoes off."

Lexi: "The security personnel are extremely thorough. This is the only way they can be sure that nobody is carrying forbidden items with them. But usually the people have simply forgotten something, to take their belt off for example. So, don't worry if it beeps!"