You really have to hand it to scientists; even when they’re working with extremely complex and confusing theories and technologies they always seem to find a way to make it fun. Case in point, Brigham Young’s physics professor Brian Anderson’s amazing demonstration of how acoustic vibrations can be targeted at very specific locations to perform a variety of important medical and engineering tasks, made much more entertaining with the inclusion of some very unfortunate Lego figurines.
Using a massive metal plate as the testing surface, Anderson shows how the sound technique known as “time reversal” can target a very small area and produce extreme vibrations in one spot while leaving the surrounding area calm. Placing some cheery Lego figures around the plate, Anderson’s laser-based sound wave targeting system topples the toys while the rest of the Lego folks stare on in abject horror.
The BYU News describes the sound technique thusly:
[Anderson] plays an impulse from a sound source and records its response with a sensor (such as a microphone) at the targeted location. This sensor catches the entire sound as the waves bounce around the environment before reaching the sensor. The team then uses software to reverse the signal and play it back. That simple reversal has the waves retrace their steps and targets them directly to the intended location.
As fun as it seems to ruin a Lego dude’s day by sending him flying without even touching him, the technology actually has some very important real-world applications including the destruction of kidney stones in patients, without invasive surgery, and even the detection of cracks or weak points in buildings and other infrastructure.