Friday, December 5, 2014

Stumped by STEM

Nothing is more humbling than trying to create a STEM lesson plan for 11 year old boys. My History degree reflects my appetite for consuming information, making logical connections, presenting a hypothesis followed by supporting arguments. So building a STEM lesson into a process is fine. But some of the science still escapes me.

My Audience has the Attention Span of an 11 Year Old

My son is part of Troop 404. I want to be a good Dad, and provide some input to their scouting skills with the ulterior motive of forcing a bit of STEM into the process. When we covered the use of Cotton Balls and Vaseline as tinder to start a fire. 11 year-olds are fascinated by fire.
State Changes: Solid, Liquid, Gas
We never really reached deep into the science of the flint and steel. Some metals burn (oxidize) at room temperature. Scrapping minute balls of metal from the flint exposes more of their surface area to oxygen - which causes them to burn. That's the trick.

We did start the discussion of the state change of Vaseline from solid, to liquid to gas as it was wicked by the cotton then burned. But you know... 11 years old.

Science: Change of State, Wicking, Oxidation,
Technology: Various tools to create fire/sparks
Engineering: A one-handed steel and flint (engineering simplicity)
Math: How to calculate the optimum amount of Vaseline (fuel) for a cotton ball (wicking framework) for maximum burn time.

From Flaming Cotton Balls to the Wisperlite Stove

The Wisperlite stove has not changed much in 30 years. I can say this definitively because I own the 30 year old version. These stoves consume various types of liquid fuel, but something else happens in the process.

In the video - did you notice that the correct way to start this stove is to set it on fire? A few drops of fuel in the lower cup, a source of fire, ignites a big yellow flame, then it burns down into an intense blue flame that sounds like a miniature jet engine. It's not like lighting your stove, or a BBQ grill.

You Can't Skip Steps to Get to the Jet Engine.

Something Else Happens

I sent an email to MSR to ask if they have a simple description of the process. Is it vaporization like the candle example above, or a venturi effect, or flash evaporation? Or, is it some combination of these processes?
Proof that Math is Hard.
You have seen flash evaporation...
but does this explain the Wisperlite?


I hope MSR will reply, so I can build out:
  • Purpose and Materials
  • Course Goals / Instruction Mode
  • Student Goals
  • Syllabus
  • Content / Arranged
  • Supplemental Materials / Activities
Next up: Tent Technology, Thermarest, Scope Reticles.

The graphics above are linked to their original sources on the web.

Thursday, November 13, 2014

Cotton Balls Vaseline and Fed Liquidity

I'm from the Jack Daniel's school of economics. That is, give me a couple shots of Jack and I'll tell you my thoughts about the economy. The key to my thought process is obtuse linking of examples (stay with me here).

Cotton Balls as Tinder

We hosted a cub scout meeting a couple weekends ago, and as host I decided to have a show and tell session to demonstrate the use of flint and steel and cotton balls as tinder to start a fire.

Adding Vaseline (a petroleum product) to the cotton ball creates a long lasting tinder. It is cheap, light-weight, water-resistant and lasts a long time. The cotton acts like a wick for the Vaseline, holding the flame while allowing the Vaseline to change from solid, to liquid to vapor, then burn. (Hey, that's all you get -- I'm an Jack Daniel's Economist. If you what physics come back at closing time).

Here are links to the starters and to a couple videos showing how this all works.

Conducting basic research in the internet is always a unique journey of discovery. While watching video number 4300 or so, an interesting question came up:

What is the optimum about of Vaseline to add to a cotton ball?  

The test:
  1. Take a plain 100% cotton ball and light it (record the burn time).
  2. Add increasing amounts of Vaseline to the cotton ball and record the burn time.
    (Change the ratio of tinder/fuel from 0% to ~99%).
  3. Determine optimum amount of Vaseline to add to get the longest burn time.
Internet video #4300 - Revelation

Can you light 100% pure Vaseline?  No, not with a flint and steel, not with a match, not with a cigarette lighter... it just melts.

Economic Link - Cotton Balls, Vaseline, and Fed Liquidity

Where is all of the Fed Liquidity?

Quantitative Easing, billions and billions and trillions of dollars, has only generated a couple percent GDP growth. The entire point of QE was to provide liquidity - to support the balance sheets of the banks and stimulate economic growth. So what happened?

Super-saturated cotton balls (economic capability) and Vaseline (pent up liquidity).

In our previous experiment we showed that a cotton ball loaded with Vaseline will burn longer than a clean cotton ball. Too much Vaseline and it will not burn at all. It has to be a lot too much, but you can try it yourself.

Maybe the Fed has created a situation where they have provided so much liquidity (Vaseline) that the economy (cotton ball) simply can't function.

PhD, Jack Daniel's School of Economic Stuff.   

Sunday, November 9, 2014

2014 BMW 328i 1500 Mile Review

We finally named the new BMW 328i.

Elle as in Elle Driver from Kill Bill.

The 2011 xDrive was Alex Forrest - a tempting, slightly wild seductress. Catherine Tramell (Basic Instinct) and Matilda Ratched (One Flew Over the Cockoo's Nest) were high on the list. 
We'll get to the reason for our selection a bit later. 
Click for larger image.

Previous Posts: 

2014 BMW 328i 1500 Mile Review

The Good

The fuel economy is phenomenal - up from Alex's 30 months average of 20.6 to nearly 26 mpg. On Friday we did a loop from Round Rock to Anderson (College Station) and back -- over 30 mpg. Acceleration is solid, turns are a bit soft, but well controlled, and braking is excellent. She pulls with gusto from the line, and a hard press on the accelerator will always deliver a bit more. I was worried about all of the shifting (horrific in Eco mode, tolerable in Comfort mode), but in Sport mode, Elle was in the right gear most of the time.     

The Bad

The only way to have fun is to drive in Sport mode or Manual, and to drive well over the speed limit. Not that I haven't tried, but Elle performs under normal conditions without complaint. It's almost tragic - her good manners (cool professionalism) belie her skill. 

The Ugly

The double-tap to turn off the accessories does not work well. ECO-mode makes politicians happy, but I can't imaging anyone else liking this feature.  The Auto-Stop Start (or AS/S) is rough on the restart. 

The Bottom Line

The 2014 BMW 328i is Elle, cold, efficient, professional. She is not the super hot, sultry Catherine, or the super-controlling Nurse Ratched. Deep down inside you know she is trouble. 
“It's the first villain [Elle Driver] that I've played in a movie that has absolutely no vulnerability and no innocence, nothing whatsoever that is like-able about her, other than she's so bad. All the other Deadly Vipers have some empathetic quality: O-Ren Ishii has this horrible past, [Vernita Green] just wants to be a mom, the Bride has been abused, but my character is just bad all the way through, there's nothing to like about her, and you're going to hate her so much.”
Daryl Hannah (on Elle Driver) from the Kill Bill Wiki. 

The first road trip: Hwy 79, 6, 30, 21, 77, 112 - none of them posed the slightest challenge. Next weekend, a run to Stephenville (183, 281, maybe back on 36).

I just know that one day I'm going to do something, and Elle is going to pluck out my eye.

[Update 11/11]: We took an unexpected run to Cabela's - from Round Rock to Buda via Toll 130. The toll road has a speed limit of 80, so I anticipated some exciting driving. Well, not so much. I would actually slow down behind a truck, down to 65-70 MPH, then pass them. But, it was decidedly effortless (sigh). Elle was loafing along, just over 2000 RPM. I finally turned on the cruise control - which is a HUGE improvement over the '11 version.