The short answer to Andy Brunning's question, of course, is that it's recycled badly and far too infrequently.
I'm typing this up on Earth Day - though it won't post for a month or so now - and am just torn up that less than 20% of the PETE is being recycled, but I watch my students through water bottles away all the time even though the recycling bin in two inches to the left of the trash can.
I don't have any idea why recycling is so infrequent because it just seems like an automatic thing to me at this point. I'm the one carrying cans away from meetings because there aren't recycling bins in our meeting rooms.
It's the jorts (2:39), the New Balance shoes, and the pasty, white legs of one Grady Hillhouse that really endear this video to me.
Yes, Grady's style is a little dry, but he does a marvelous job showing very basic concepts of engineering as they apply to our everyday world and not just talking about the concepts but rather by building and showing small, graspable demonstrations.
In this video, Grady shows...
how much force it takes to break two 'identical' concrete cylinders - one under tension, one under compression
concrete beams (fairly thick beams) tested to failure with a four-point break test - a beam with no reinforcement, with 'rebar' reinforcement, and with pre-stressed 'rebar'
We are building a 38’ wooden sailboat designed in 1934 by William Atkin. Atkin calls this particular boat “Ingrid” but our vessel will be named “Arabella”, once built we intend to take her to the most far flung corners of the world. We are documenting every aspect of the build as we go, we hope to inspire and educate people along the way and to experience as much of this wonderful world as possible in the process.
In this week's episode (or rather the episode from April 13, 2018), Steve (the guy with the awesome beard) is looking at using various metals as fasteners on the boat. Apparently it matters whether the metal is very reactive (less noble) or not very reactive (more noble).
Specifically, Steve puts various metal samples in salt water alone and in various combinations to see which metals should and should not share fasteners in the boat.
I haven't yet checked out the follow-up where Steve looks at the effects of the metal corrosion on various woods.
While standing on a frozen lake and trying to jackhammer through said lake with a red-hot jackhammer tip seem like a real, "hold my beer" kind of moment, that's not why I posted this video.
Instead, it's because of the utterly surprising but in retrospect kind of obvious results from the red hot jachammer tip.
See, the first four minutes are the guy (host of the Hydraulic Press Channel) just digging his way through half a meter of ice with a non-red-hot jackhammer. Meh...
It's at 4:19, though, that the material science gets real.
(Spoiler...watch the video first, at least the part from 4:00 through 4:30 before you highlight the text below)
At 4:19 the red-hot jackhammer tip meets the ice, and the jackhammerer learns a little bit about the effects of phase changes on steel. The tip - now properly softened via BCC to FCC phase change, curls right in on itself like it was made of soft butter.
He and his wife laugh like loons as the tip curls into nearly full U-shape.
Brilliant...
To quote at 4:49, "I think this is bad idea."
Then we're treated to an up-close replay at 5:03.
After about 5:40, then, there's nothing much to see here. Just a guy hammering away at blocks of ice he's cut from the lake's surface.
The money shots are all between 4:00 through 4:30 - or maybe through 5:30 if you really want to fill a little more class time.
I'm always appreciative of someone who can explain complex ideas in such a simple fashion, and Grady from Practical Engineering is such a someone, using a simple model to show the differences in forces in the original and revised design for the walkways.
