non-magnetic steel?

[AGCB97]

Sparks yellow.

What or where is area 51?

 

[JimDawson]

What or where is area 51?

http://content.time.com/time/specials/packages/article/0,28804,1860871_1860876_1861006,00.html

 

[eugene13]

Groom Lake in the Nevada desert, supposed to be a lot of secret aeronautical stuff going on, flying saucers, aliens, etc.

http://content.time.com/time/specials/packages/article/0,28804,1860871_1860876_1861006,00.html

 

[graham-xrf]

If you weigh your sample very precisely
and then fully submerge it in water and measure the exact volume by how much water it displaces, you can arrive at the true density in g/cm^3 or
pounds per cubic inch etc. Crying out Eureka!, he proved the kings crown wasn't pure gold and somebody in the crown factory got drawn and quartered.

I do love that!
As I recall from high school, the whole deal about displacing water to measure a volume was a darn pain, unless the side of the container was calibrated already, as in a glass measuring tube (flask), and the doodad was small enough to fit down it. Anything involving what runs out a spout was just doomed!

WAY easier was just to weigh it suspended on a balance already zeroed for the weight of the (very) fine wire suspend, then raise up the jar of water from beneath, and check out the new weight when surrounded by the water, feeling the benefit of some buoyancy.

Here also is where you have to completely get the difference between density, and specific gravity.
For us, every millilitre weighs 1 gram, or every litre weights 1 kilogram.

The trouble is, it is relatively clear, the difference between the pure gold crown, and the debased metal version.
Not so easy is the difference between various metal alloys unknown!