This CNN article explains one of the airports annoyances that we all encounter during our security check: removing our laptops, phones, Apple watches, etc. from our carry-on bags. This is something that happens at airports in poor or small countries, but also happens in airports in wealthy countries, like the US.

The main reason you have to remove your laptop from your bag is because its battery and other mechanical components are too dense for X-rays to penetrate effectively – especially if the scanning system is old. The same goes for power cords and other devices such as tablets and cameras.

With these items in your bag, security officials can’t use the screened image to determine whether a risk is present. They’ll have to flag the bag for a physical search, which slows everything down. It’s easier if all devices are removed in the first place.

A laptop inside a bag can also shield other items from view that may be dangerous. Scanning it separately reveals its internal components on the screen. In some cases you might be asked to turn it on to prove it’s an actual working computer.

With newer multi-view scanning technology, security officials can view the bag from multiple angles to discern whether something is being covered up, or made to look like something else. For instance, people have tried to mix gun parts with other components in an effort to pass checked baggage screening.

– From CNN

The modern 3D-scanners at some airports eliminate the need for travelers to remove their electronic gadgets from their carry-on bags, since the scanner can examine multiple angles of any suspected gadgets, thus lowering security risks.

The article also explains that “The tall frame you walk through is a metal detector. Its purpose is to uncover any weapons or other illegal objects that may be concealed under your clothes. Airport metal detectors use non-ionizing radiation, which means they don’t emit X-rays.”