/diy/ - Do It Yourself

>>1534234
>measure the natural frequency of the earth by placing a sensor several hundred feet in the ground and detonating a small explosion there, and measuring the time between echoes.
Unless that "small explosion" is a nuke, the echo won't be audible AFTER ITS SECOND PASS THROUGH THE PLANET. If they seriously want to try this, tell them to listen for an earthquake and try to sift the echos from the background noise. If they seriously want to analyze seismic echos, forget digging the hole and setting up your own sensor. Instead, look up actual seismograph data from the date of a major earthquake that will actually stand out globally.

Also, you may want to keep this from them to let them figure it out themselves, but the Earth is acoustically heterogeneous. It doesn't have a single natural frequency since echo time is path dependent. If they're really good with their analysis, they should be able to calculate how big the core is.

>>1397094
>No, it must be normal wool
>>1396904
>electrically conductive cotton without losing cotton-ness

>>1365051
Why thank you. It's just a pet peeve of mine, but I'm glad it made a difference.