Red Hot JACKHAMMER Vs. Frozen Lake

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.

Scrub Daddy Science

I bought a Scrub Daddy a couple of years ago and have been using it to demonstrate glass transition in polymers since then. It's good, however, to know a little more science than what I've been explaining ("it's a polymer, and they have phase transitions from rigid to flexible").

The above video shows the phase transition and the 2012 patent (linked here) for the Scrub Daddy. The blog entry associated with the video has more information as well as data from a few experiments (FTIR, for example) done with the Scrub Daddy.

In a semi-exciting detail, the video also shows that the thermoplastic polymer from Education Innovations is the same polymer as the Scrub Daddy. Conveniently, I already have that product in my storage room.

How cool is that?

But wait, there's more...





And also a video that I don't understand in the least. It's a wordless video of somebody pouring slime on a Scrub Daddy and squishing it with what I believe to be added sound effects. Clearly the internet it the realm of the long tail.

Phase Transition in Steel

That's an interesting addition to the iron wire demo: a glass rod to exaggerate the 'dip'.

The glass rod makes sense because it's non-conductive enough to not be too dangerous, I would think.

The graphing on the video really makes the phase transitions remarkably visible, though.

I like it.

The video's description gives a little more detail as well as the reason for the slow, overall downward slope.

A steel wire is heated up by a current and it expands. When the phase transition temperature is reached the wire takes up additional energy which cools the wire down for a short time and shortens it. 

This step can also be observed in the opposite direction when the current is switched off and the wire cools down. When the phase transition takes place the wire is heated up and it expands for a short time. 

Over three cycles the thin wire gets already worn out. Is is deformed so that the diameter, the heating power and the temperature is not equal along the wire and the phase change occurs more distributed over time.

Heat treating tool steel -- the phase change

I'm going to trust the video's description (copied below) when it says that the flashes of light at 0:32 are visual indications of the BCC --> FCC phase change that takes place at 910 C.

Visual indication of tool steel phase change to austenite when heat treating. Small pools of iron are forced from the steel as the volumetric change takes place and small amounts of carbon are burned off.

So, my understanding from reading that, is that the BCC (ferrite) --> FCC (austenite) change squeezes some of the carbon out of the structure. That carbon then - because of the high temp and the presence of oxygen around the steel - burns off in the flashes that we see.

Can anybody tell me that I'm reading the situation correctly?

Build and Modify the World Around You with FORMcard | WIRED

I need to buy myself some Formcards (available here in the US - don't search Amazon because their selection is crap and ridiculously pricey).

I really dig the colors, and I'm looking forward to using them to demonstrate the idea of glass transitions in polymers (something we've seen before on the blog).

Mitch Anthamatten Explains a Shape-Memory Cycle Involving Strain Induced Crystallization

Wait, a shape memory polymer?

There's a bunch of good connections here to what we teach in our material science course.

• The polymer switches from being largely amorphous to largely crystalline on addition of strain.
• The addition of heat energy then causes the polymer to shift back to amorphism.
• The phase change happens around body temperature, like the stints we talk about.
• We have a solid-state phase change.
• At 0:55, the professor says the energy is 'enough to melt those crystals.' I'm way less knowledgeable and more a neophyte about all this than he is, but that sounds wrong to me. I don't think of a crystalline solid changing to an amorphous solid as 'melting.'

All that in less than two minutes time...

That's better than watching the Kentucky Derby.

For the undying 9/11 MORONIC JET FUEL ARGUMENT

It doesn't take a whole lot of fancy learnin' and figurin' on the back of an envelope (like Grandpa used to do) to prove that steel softens long before it melts.

We've highlighted the phase diagram of steel, our iron wire demonstration, and even the downfall of the World Trade Center (as the above video references). All three of these posts discus the phase change that takes place around 910C from body-centered cubic (not very workable) to face-centered cubic (far more workable as shown above at 1:45). In the above video, he does the same but using Fahrenheit references.

Theory is all well and good, but proof this succinct and effective is brilliant.

We're going to have to adopt the 'glowing hot rod' drop instead of a mic drop now.

I will warn you that he uses the word retarded at about 0:39. It's not exactly a vulgar word, but it's one that we should probably avoid in our classroom.

Coffee Joulies - cool coffee faster

I know what my wife's Christmas gifts are going to be this year. She, admittedly, likes her coffee pretty hot, so I don't know whether that will be the prefect temperature for her, but the science is outstanding.

And that's what matters, right? Whether I find her gift interesting, right?

The Coffee Joulies are filled with a phase changing material that has a transition temperature at whatever appropriately hot coffee is supposed to be. Hopefully it's right.

Sep 11 - "Why the Towers Fell" - Nova PBS

It is human nature to look back with one eye to the future. If we can just figure out why that happened, we can make sure it doesn't happen again. That is, at its core, what failure analysis is all about.

NOVA, the PBS series, produced the documentary "Why the Towers Fell" looking at the conclusions of the engineers and scientists on the government's exploration panel attempting to answer the titular question. In their findings there are a number of material science connections...

• tradoffs among cost, weight, and strength - particularly at 11:30
• design constraints - 12:45 (designed for impact of a Boeing 707, the largest at the time of design)
• mechanical testing methods (sheer, tension, vertical load) - 33:30
• heat softening of the steel - 37:45, 44:35 (and throughout in small mentions typically as "the heat would have softened the steel")
• failure analysis - all throughout, particularly at 45:00

NOVA also posted a website of information related to this episode, much of which is still online. Some links are starting to fail, however. The best of these are a very readable summary of the findings, the engineering history of the Towers, and a java interactive showing what metal atoms do as heat is applied.

This one's tough for me to post and was even tough for me to watch. I didn't have a direct connection to the tragedy of the Twin Towers, but I had at least one student who did, who knew someone on one of the planes. If it isn't already obvious, be aware that some of our students - or coworkers - may have closer connections and may still struggle with memories of the incident, of loved ones who were closer to the Towers, or even - like me - have memories of being in the Towers and being two or three relationship steps away from the tragedy.

Mini Materials Camp

Each time there is an MS&T conference, the ASM folks try to be there to run a mini-materials camp. The ASM folks invite local teachers to bring their classes (sometimes even paying for transportation) and see some of the glory that is materials science.

This series of videos shows the process of casting tin using a microwave oven. The process of sand casting is fascinating to watch and still an important industrial process.

The process is broken up into five parts - the remaining four of which are after the jump.

Today's post finishes with another demonstration from the mini-materials camp: the phase change of iron wire.

The mini camps aren't nearly a replacement for the week-long summer camps, but they're great ways to expose your students to materials science if you happen to be lucky enough to be in the area of an MS&T conference - like the Indianapolis folks are this fall (September 2013).

What is ANGIOPLASTY and STENTING?

I'm guessing percutaneous coronary intervention is a phrase that is just casually thrown around in some medical fields, but it seems a pretty daunting introduction to me. The animation shows how balloons and stents - assumedly made of memory metal - are used to open a clogged artery.

It's a great explanation and illustration of a fairly complex process that would be nigh impossible to actually film from this same perspective.

Now I just need to get my hands on a stent to show in class.