Question: What's your best experiment?

Kevin Motherway answered on 10 Nov 2014:

Coolest thing I ever saw in an “experiment”? I was doing a Geophysical survey in Wicklow at about 4 am, as we were doing a seismic survey to determine how cracked the rocks beneath a potential route for a motor way were. We had to do it at 4am as we were sending vibrations (seismic waves) into the ground for our survey and vibrations from trucks up to 10km would interfere with the survey. So you could literally see how the vibrations were travelling through the ground on a graph on a computer screen. we got our survey done by 5 am, but in the distance you could hear traffic picking up and trucks driving and even hear when they changed gear as it was such a still morning. But the cool bit was the vibrations from the trucks could travel through the ground from 10 km way faster than the speed of sound; so you could see the vibrations change on the computer screen as a truck changed gear from 10 km away and maybe 3.5 seconds later HEAR the truck change gear. This difference in travel time is exactly what is used to figure out where the epicentre of an earthquake is located. Cool