Teaching Math

FAILING THE MATH TEST

A ten-year-old Jewish boy was failing math. His parents tried everything from tutors to hypnosis; but to no avail. Finally, at the insistence of a family friend, they decided to enrol their son in a private Catholic school.

After the first day, the boy’s parents were surprised when he walked in after school with a stern, focused and very determined expression on his face. He went straight past them, right to his room and quietly closed the door.

For nearly two hours he toiled away in his room – with math books strewn about his desk and the surrounding floor. He emerged long enough to eat, and after quickly cleaning his plate, went straight back to his room, closed the door and worked feverishly at his studies until bedtime.

This pattern of behaviour continued until it was time for the first quarter’s report card. The boy walked in with it unopened – laid it on the dinner table and went straight to his room. Cautiously, his mother opened it and, to her amazement, she saw a large red ‘A’ under the subject of Math.

Overjoyed, she and her husband rushed into their son’s room, thrilled at his remarkable progress. “Was it the nuns that did it?” the father asked.

The boy shook his head and said “No.”

“Was it the one-to-one tutoring? The peer-mentoring?”

“No.”

“The textbooks? The teachers? The curriculum?”

“No”, said the son. “On that first day, when I walked in the front door and saw that guy nailed to the plus sign, I KNEW they meant business!”

Signs at a bowling alley in Katy, TX.

Shoe Rental: Adults: $2.00. Seniors and Children: $2.00.
Hours: Sun-Thurs: 10:00 AM - Closing. Fri-Sat: 8:00 AM - Closing.

laser beam diffusion at satellite distances

Some colleagues were recently discussing the efficacy of using laser transmitters to secure communications amongst orbiting satellites.  In particular, they were under the opinion that point to point laser communications would be immune to eavesdropping.

Eventually, I couldn’t resist the urge to say, “Wait.  Stand back.  I’m going to do MATH.”

Some 1996 information from JPL described a typical space communications laser as having a beam diffusion angle of 3.5 microradians  (about 0.0002 degrees if I did the conversion correctly).

Assuming I did the rest of math correctly (it’s been awhile since I’ve done Trig calculations), the reference beam diffusion angle would result in a perfectly targeted laser completely covering a 10 Meter Target at a distance of ~1,770 miles.  If the sender and receiver are further than ~1,770 miles apart, an eavesdropper would only need to position themselves somewhere behind the receiver along a line of sight.

To put that in perspective, at the International Space Station’s Altitude, the average orbital distance (once around the world) is ~26,000 miles.

Basically, even a James Bond Super Villain with excellent cloaking technology aboard a massive constellation of close formation nano-satellites needs to assume their laser based communications are subject to eavesdropping.  Actually, the cloaking technology would only be useful so long as they maintained “radio silence”… the moment they starting transmitting laser emissions; they’d give their position away.

 

Post EMP refrigeration

A high profile security consultant recently wrote a book (fiction) that was set in a post-apocalyptic situation which occurred after an EMP burst obliviated modern electrical systems.  The premise plays pretty loose with the laws of physics, but people seem to like these kind of stories.

If you’ve been wondering how modern life could continue if electricity systems were interrupted, here are a few ideas for keeping your cool.  Don’t blame me if worried neighbor sprays you with a fire extinguisher.

Refrigeration without electrically driven compressors is trivial.

Below is a primer on using chemicals.  Time Magazine had an article in 2005 about a guy in Hawaii that made ice by channeling wind thru a pipe to induce heat transfer (idea known as Ranque-Hilsch vortex tube).  Or you could rig your exercise bike to the compressor motor’s shaft.

You can find more ideas by googling “ice without electricity”.  Or ya could just buy a $49.99 surge protector.
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Ammonium chloride.    (NH4)(Cl)
Ammonium nitrate.      (NH4)(NO3)

Mix either one with water to create an endothermic reaction and freeze things.

The (NH4)(Cl) can be bought n stored; or you can make it with household ammonia and hydrochloric acid.  The  (NH4)(NO3) is common fertilizer.  Most gardeners already have this sort of stuff on hand.

Before trying this at home I’d watch some MacGyver reruns and find a chemistry student  or H.S. Chem Teacher to advise on mix ratios and containers and demonstrate.

“PowerPoint makes us stupid,” Gen. James N. Mattis of the Marine Corps

Really like the last two paragraphs…

Funny printer hacks for the office.

A friend at an organization having budget issues recently suggested hacking the printer displays to show a message such as “insert 25¢”.

Since many office printers also have fax machine capabilities, and thereby have some sort of internal speaker, the idea evolved into adding some sound effects:

• washing machine spin cycle
• garbage disposal eating silverware
• leaky faucet drip
• sounds of a paper jam happening:  not an actual paper jam, just the sounds of one.
• microwave oven:  a fan/humming noise followed by ding at which point the printer stops and has to be reset for another 1.1 minutes (or another 25¢ must be inserted) before it will finish printing your output.
• fax machine noises:  use status display and sound effects to indicate the user’s print job is being faxed to destinations such as newpapers, IRS, FBI, tatoo parlor, foreign embassy, kinkos/officemax print service, etc.,

For office printers which do not have fax capabilities, but do have ports for adding print server cards or other modules, perhaps an insertable sound card could be devised.

some feature enhancements for the spell checker utility…

  • inappropriate suggestion checker… hmmm…. guess this could be two features
    • 1… actually checks your work for inappropriate suggestions
    • 2… makes inappropriate suggestions to you as it checks your work
  • overused cliche checker
  • unintended insinuation checker
  • incriminating double entendre checker

stupid windows tricks: c:\stuck\ and c:\stuck_\ and c:\stuck__\

I have never understood that for years, you have been able to create a folder with a space at the end of its name in a script. But try, just try, to delete that folder.  You can’t delete it in Windows File Explorer.  In fact, the only way to fix that I have found, is hope its a really long folder name, drop to a command prompt, and delete it with “Del folder~1”.

Well, the documentation for Windows Explorer specifically states that it may not support all the naming conventions of the underlying file systems.  Of course, it would be entirely reasonable to expect it to fully support the naming conventions of any Microsoft file system, but MS seems to operate under an unusual definition of “reasonable”.

You don’t need a script to create such folders, just the command prompt. This will work just fine: mkdir ".\Space \". Even better, dir /X may fail to reveal this as a long filename (by definition, any filename containing a space is a long filename even if it’s eight or fewer characters in length), in which case there’s no way to use dir to make it obvious there’s an abomination in the list of folders.

Note that mkdir "Space " won’t give you the trailing space in the folder name.  You need to use the quotation marks and the slashes.  Similarly,rmdir "Space " fails to remove the directory, but you can remove it with rmdir ".\Space \".

File this under “Stupid cmd.exe tricks”.  Its a fun way to use 3 lines of script to really annoy off your IT co-workers.

Heh, create three sibling directories named “stuck” where they have one, two, and three trailing spaces – then sit back and watch the consternation. It will look like there are three folders with identical names under the same folder (impossible!), and none of them can be deleted with Explorer.

improveverywhere.com

—–Original Message—–
From: xxxxxxxxxx
Sent: Friday, July 10, 2009 3:15 PM
To: xxxxxxxxxx,xxxxxxxxxx,xxxxxxxxxx
Subject: http://improveverywhere.com/
This is hillarious.
A quote from a victim of one of their pranks:  “It’s like a David Lynch movie in here. It doesn’t make sense.”