What does it do?
The short answer is: it opens doors. The long answer is much more timey-wimey.
The Doctor tries their very best to be a pacifist, consistently seeking to resolve conflicts with words rather than weapons. So any device the Doctor employs is meant to assist, not harm. As the Tenth Doctor articulated, the sonic “doesn’t kill, doesn’t wound, doesn’t maim.” The sonic screwdriver is, on the other hand, very good at opening doors. Primarily used as a lockpicking device, the Sonic is renowned for allowing the Doctor and their companions access to places that they really shouldn’t be entering.
But it doesn’t end there! Despite being a small device with no visible interface, the Sonic has a zillion functions, operated by a psychic interface. Users merely need to point and think, and the Sonic will whir into action. Some of its uses include:
- Scanning for alien tech
- Disabling weapons
- Detonating landmines
- Boosting phone signals across time and space
- Scanning medical information
- Boosting X-rays
- Writing (sometimes it’s a pen too!)
And let’s not forget its ability to reverse the polarity!
The Sonic is the ultimate multipurpose tool, enabling the Doctor to quickly join the fray and fend off threats. And, of course, it can also be quite helpful when assembling furniture.
So, how does it work?
As its name suggests, the sonic screwdriver operates on ultrasonic sound waves. It sends out vibrations to interact with the surrounding environment. That’s what the whirring sound is! How these vibrations actually perform half the functions the Sonic is known for, well, only a Time Lord could fully explain. Although other species have been seen using similar sonic probes, sonic screwdrivers are predominantly referred to as Gallifreyan technology. However, the Doctor, in defending their use of the Sonic, has hinted that they made their own: “Never had a lot of cabinets to put up?” It remains unclear if they were speaking specifically about their own Sonic or if they were implying that they were the inventor of the very first sonic screwdriver.
But why Sonic?
Again, sound waves! Also, the Doctor probably thinks it sounds cool, which it does.
When did it first appear?
The sonic screwdriver made its debut onscreen in the 1968 story, Fury from the Deep, where the Second Doctor, played by Patrick Troughton, uses it to… unscrew some screws! In its initial appearance, the Sonic looked more like a whistle. Images of this version are unfortunately scarce due to all six episodes being absent from the BBC Archives. Thankfully, Fury from the Deep was brought back to life through animation in 2020.