diamond in piranha. #video #materials another #The-Action-Lab video, but not full of misinformation as far as I can tell. Also includes demos of piranha on a cellulose sponge and a hot dog. Diamond results: inconclusive.
on 02024-04-04can #ultrasonic waves eat metal? #video demonstrating ultrasonic cleaning and giving an introduction to acoustics. Claims that sound pressure at a given “amplitude” is proportional to frequency, but the WP article on the absolute threshold of hearing says that 20μPa = 0.98pW/m² at 1 atm and 25°C without giving a frequency, so I’m not sure what definition of “amplitude” would make this true. Displacement, I guess? Immediately afterwards, though, he equates amplitude to loudness, so I guess he’s just wrong. Also the video has lots of worthless talking head footage. By “eat metal” apparently he means tear gold leaf apart. But he says it’s “brass foil”, thickness unspecified. I guess we can relegate "The Action Lab" to the #fakenews #misinformation category.
on 02024-04-04