Bonus Explanation-The Doctor's Ray Gun
After finishing the article I came across this frame while scrubbing through Day of the Moon . It did perplex me a bit as I was always under the impression that the sonic screwdriver was harmless. Many a Doctor before Eleven have stated this fact. The picture shows the harmless screwdriver shooting a beam at a Silent. First, I'm still trying to figure out what acoustic science would both take down an enemy at a distance and also shoot out a wiggly green light beam. I'll possibly address that in a future post about just how harmless that screwdriver really isn't.
When the Doctor shot the weapons out of the Silurian's hands in The Hungry Earth/Cold Blood he held it upright at first. It was meant to show that the Doctor would not use it to harm a living creature as pointing it directly at the Silurians would be deemed aggressive. But later in the same episode the Doctor purposely points the screwdriver at the pursuing Silurians and shoots the weapons out of their hands. As Restac steps forward, he points it directly at her and states, "Ah ah ah. Stop right there or I'll use my very deadly weapon again." It is at this point that the screwdriver transitioned from a useful and harmless tool to a serious weapon. But remember, the Doctor doesn't like guns...
Conclusion
Most of the nearly 900 uses recorded in my dataset can be described by today's acoustic sciences, though not to the level the Doctor's screwdriver can manage. Advances in these sciences will, hopefully, bring that functionality closer to what is seen on the screen. Everyday there are more advances that could give rise to such a device. But what about those other uses? And what about those uses that can't be explained? The ones that you can only stare and think "It's a fracking Magic Wand!" Think back to Eleven in Craig's house, or while he was in Alfie's bedroom in Closing Time when the Eleventh Doctor pointed the screwdriver at the baby lamp and all of a sudden there was a wondrous and magical light show. In that, and other unexplained uses, I just shake my head and don't speak about it. And let's even talk about the function, Threaten, when the Doctor points it in someone's direction, it buzzes and lights up and then, nothing happens. But just remember, this is a science-fantasy show and originally they never worried about explaining how the screwdriver did what it did. Looking back, it's a wonder just how many uses can be explained with proper acoustic science. Maybe you'll stop looking at it with those Harry Potter eyes...