Explaining concrete while getting buried in it

I ranted last week about the lack of 5-10 minute YouTube videos, so I won't rehash that grumble pile this week.

Instead I'll mention that there's an urban myth (frequently disproven) that construction workers on the Hoover Dam either fell into an couldn't get out of or were purposefully dumped into the un-set concrete used to create the dam itself.

"No, they weren't," is the short answer. The long answer has to do with the inhumanity of such a practice, the long set time of concrete, and - as this video above shows - the high density of wet concrete.

Today's video sees Dr Derek in a wetsuit trying to fill a sphere with himself and a batch of wet concrete while cutting back and forth to various explanations as to the science of concrete, the most widely used material we have and the underlying backbone of our modern world.

And at about 9:30 we get the clear explanation as to why bodies were never sunken in concrete: bodies float in concrete. 

Yes, the rest of the video is well done, explaining the history of concrete - primarily around the Roman discovery, the science of concrete setting, slump testing, ingredients in different concrete batches, clunkers, the environmental effects of concrete production, cement v concrete, and much more.

It's a great, great video.