Divemedic

Teaching

Sometimes when you are teaching, you have to simplify a problem so that students can understand the concepts involved. I will explain. When I was a teacher, I was trying to explain to my Honors Class (I think chemistry, might have been physics. It’s been awhile) how to do a unit conversion using a method called dimensional analysis. It’s a pretty common way of solving equations that is used in the physical sciences.

I first learned the dimensional analysis when I was in the Navy at NucField A school and at Nuclear Power School. It’s handy for solving a lot of things. Dimensional analysis is a method for solving various problems that, once mastered, allows for the rapid solution to unit conversions, various physical problems (like Ohm’s law), medication dosage calculations, and more. It reduces calculation errors and is a very handy skill to have. I use this method all the time to calculate drug dosages, and used it as a firefighter to calculate hose pressures and other useful numbers.

I was teaching it to my students by giving the students a list of things I wanted converted from one item to another. The worksheet that I gave them was a list of problems that were easy to solve, but included the following instruction:

Show all of your work, including the proper setup of the dimensional analysis method. Your work is part of your answer, and any problem that does not include the showing of your work in the proper format will be marked as incorrect and will receive no credit.

The questions were things like:

  • Convert a $5 bill to nickels
  • How many toes would 22 people have?
  • How many legs would 123 ants have? (they each have 8 legs)
  • etc

So one of my students answered:

  • 100
  • 220
  • 984

And promptly got a zero for a grade. Yes, the math was correct, but I wasn’t looking for the mathematical solution, but a solution that showed me that he had mastered the method of dimensional analysis. Anyone with fourth grade understanding of arithmetic can tell you that 22 people have 220 toes. I knew that they could do simple math, because it was a requirement to have already passed Algebra and Geometry as a prerequisite to even be in my class. This was an honors course where students could receive college credit at the end of the course.

It was important that they understood the concept so when we went on to more complicated problems, they would have the skills needed to solve them. It wasn’t about the math of that particular problem, it was about knowing HOW to use dimensional analysis. That way, when you get a problem that goes like:

A sample of calcium nitrate, Ca(NO3)2, with a formula weight of 164 g/mol, has 5.00 x 1027 atoms of oxygen. How many kilograms of Ca(NO3)2 are present?

The problem can be solved without too much difficulty. The easy problems were not a test of math ability, they were a means of learning a new method for applying math skills that the student already has. A “learn to walk before you try to run” sort of thing.

The child’s parent wrote me and demanded that he receive full credit because he got the correct answers. I tried pointing out the instructions and explaining the reasons behind showing your work. No go. The parent argued that “in the real world” no one cares how you got the answers, just that you ended up with the correct answers. I tried pointing out that, this being school, demonstrating that you have mastered the method is more important than getting the correct answer. The parent continued to argue and demanded that the student receive credit. I refused. They even told me that they would get a lawyer involved. I told them “good luck finding anyone that will support you not showing your work on math homework, when the instructions clearly required it.” Then I told them if lawyers were to be involved, I would be happy to give them my attorney’s number, and their attorney could call mine to arrange a meeting. They hung up on me.

So the parents went to the principal. Nope. They went all the way to the school board, to no avail. The parent finally pulled the kid out of my class and put them into a low level environmental science class.

In this case, the parent did the child no favors.

EDIT: I am editing this to give an example of how dimensional analysis works. Here is the example:

Convert 1 week into seconds:

*Terms on the top AND bottom of the equation cancel out, leaving: (1*7*24*60*60s)/1=604,800 s

By Divemedic, ago

Lessons

A father in Baltimore was beaten to death while protecting his children from a group of teenagers and adults who wanted to finish a fight that started at school. Christopher Wright was outside his home Friday when he was attacked by three teens and two adults who were looking for his fiancée’s 14-year-old son, who had gotten in a fight with another teen at school earlier in the day.

When Wright told the group that the boy was not going to come outside to fight, they told him, “’If he’s not going to fight, then you’re going to fight,” then they administered a gang beating. Wright had a seizure and began posturing, then later died of a traumatic brain injury. No charges have been filed against any of the individuals involved.

There are a few lessons to be taken from this incident:

  • Stay out of cities, especially ones that are Zone 3 or higher.
  • Carry a weapon
  • If it’s 5 on 1, it isn’t a “fair fight” anyhow.
  • Don’t “take your beating like a man” because that may mean your death or permanent disability
  • oh, and get your kids out of public schools. They have become little more than prisons containing violent criminals
  • If someone comes to your home looking for a fight, retreat inside, arm yourself, and call the cops.
  • Have good cameras recording the outside of your home
  • Did I mention avoid liberal enclave shitholes?

I also would point out that there was no description of the attackers other than “teens and adults” meaning that they are likely black.

The school in question is Brooklyn Park Middle school. It is below even Maryland’s abysmal average for schools, with 37% of students being at grade level for English, and 14% in Math.

By Divemedic, ago

Book Bans

Stories abound on so-called “book bans.” The right is pulling books from school libraries because they instruct children on how to perform sex acts upon other children or on adults. It’s a disingenuous argument. Librarians are acting all offended because a school is choosing not to carry books that are inappropriate for children. The books can still be purchased by those who choose to do so. They can still be read, are still being published. They haven’t been banned at all.

Not so with other books. It was just five years ago that the left cheered as Amazon pulled a book from its store. That book, published by Defense Distributed, was the text version of the step files required to 3D print the Liberator pistol. That book was subsequently banned by a US judge. It is no longer published. It can’t be bought. No one can read it, unless they find a bootleg copy from a site like Pirate Bay.

By Divemedic, ago

This

To those who claim that the cops and military won’t confiscate your guns…

By Divemedic, ago