Child’s Play

By The Metric Maven

Bulldog Edition

Recently I was visiting Albuquerque New Mexico. While there, I went to the National Museum of Nuclear Science. It was an interesting enough experience, but it was the gift store that made the largest impact. On the back wall was a number of educational laminated exercise sheets. They are about 440 mm x 305 mm in size. The first to catch my attention was a sheet intended to “educate” young people about U.S. weights and measures. The U.S. weights and measures sheet seemed very simplified, and is reproduced below:

The typeface is large and legible, about 10 mm or so in height. There is plenty of space between the lines of text and the graphic design is very open and accessible.

When I found the metric version of this “educational resource” I was aghast. The typeface is reduced to about 5 millimeters in height, and the graphic design is cluttered. Clearly when one looks at this metric presentation, and compares it with the U.S. version, the metric version is just so complicated that only a Nobel Prize winner could understand it. The message is clear, U.S. Ye Olde English is simple, the metric system is complicated. The metric version is reproduced below for comparison:

The U.S. version has no metric equivalents on it. The metric version has Ye Old English equivalents on it. This is the first source of clutter. The second source of clutter is the prefix cluster around unity. The length section has millimeters, centimeters, decimeters, dekameters, hectometers and Kilometers. The same set of prefixes is used for the liter and the gram, with Ye Olde English equivalents added.

In my essay Naughtin and 1929, I wrote about a newspaper that was introducing the metric system that year and made it appear much more complex than needed. What was done there seems like a peccadillo compared with this group of Mormons making coffee. We are treated to a history lesson  that explains: “The Metric System was first proposed in France in 1670 by Gabriel Mouton. It is a system based on mathematics and not the size of a king’s body part.” No, the system part of the metric system was proposed by John Wilkins in 1668. It relies on scientific phenomena as a basis, and simplicity in expression. It is pointed out that the U.S. is “the only major country in the world not to adopt it.”

This product is called a Painless Learning Placemat, and has a 2014 copyright, so it is not a relic from the 1970s, it is contemporary obfuscation. At the bottom of each placemat is “Made in U.S.A.” The Ye Olde English measures placemat does not have the center section taken up with a history of measurement, and the SI prefixes with the prefix cluster around unity added. It does have SI Punctuation Rules. Rule #2 is not to use plurals on the unit symbols, so it’s: “hg not hgs.” One would not want to get their hectograms in a bunch. Rule #3 is there are no periods after units, it’s: “cg not cg.”, so make sure you have your centigrams without periods, as you will also be using lots of centigrams in your new fantasy metric world.

I will give the author(s) some credit for the other rules—mostly. Rule #1 is to leave a space between a numerical value and its metric symbol. They have 5 g not 5g. Rule #4 is to use a space instead of a comma for large numbers. However, the space they use in their example is so small that a young person (or the instructor) might be confused that a space exists. The kerning is awful:

Perhaps 10 000 and 10,000 might have been a better example?

Rule #5 advocates a leading zero on decimals. Their example is 0.6 mm not .6 mm. This is good, but when possible in a list of presented values, whole numbers are most expressive. 600 μm is succinct and this possible choice should be explained.

The reverse side of this placemat has “metric exercises” for the young person. They mostly involve the prefix cluster around unity, and therefore are for “practical” everyday use:

There are many more exercises in futility on the back side of the placemat. One is to “Draw a line from the prefix  to its correct numerical value.” These include mm, cm, dm, dk, hm, km with 10, 0.01, 0.1, 100, 0.001, 1000. One is then to take the prefix symbols and match them with the full prefix cluster. This includes mg, kg, dg, dkg, cg, hg, with dekagram, hectogram, milligram, kilogram, decigram and centigram. Those of you that are metric pedants will immediately notice that rather than using da for deca, this placemat has dk instead. It seems apparent to me, that when confronted with dkg, it’s possible for a young person to see it as a decikilogram. Well over 75-80% of the area of the backside of the metric placemat is taken up with the important task of understanding hecto, deca (sorry….deka), deci and centi. Metric is not better by 1000 on this placemat, it’s ten times worse. This “educational tool” is an unintentional argument for eliminating the prefix cluster around unity.

What young person would choose metric over Ye Olde English when they see nothing but complexity staring at them? The idea that more prefixes exist, such as Mega, Giga, micro, nano and so on, would certainly produce loathing for this complicated system, and budding American exceptionalism could possibly follow. The back side of the Ye Olde English placemat is far less dense, and tells you what you don’t have to remember:

The placemat does not mention Troy versus Avoirdupois pounds, even though silver and gold are weighed with Troy, and that seems fairly important. If a child understood the actual simplicity of the metric system, without the prefix cluster around unity, and was not conditioned with this misleading pre-metric placemat to see the U.S. weights and measures as simpler, they would revolt when they came across this set of exercises on the back side of the Ye Olde English placemat:

The metric placemat is so padded with worthless and pointless exercises, that it would probably convince the poor child that the Ye Olde English reverse side is easier than the back of the metric placemat. Considering the convoluted and misleading metric backside, it might actually be just about as bad—but of course it’s only typical of ignorance in action.

The U.S. placemat does not bother to relate any of the U.S. measurement units to metric units, but the metric placemat does—when it should not. In an actual adoption of the metric system, one changes to metric exclusively, and never looks back. The U.S. placemat has a small box explaining how to convert Fahrenheit to Celsius. On the U.S. back side, one is to parrot back this simple algorithm. The metric place mat has extensive exercises to convert a list of Celsius values to Fahrenheit and vice-versa.

What young person would not be repelled by the metric system when it’s presented in such an overly and artificially complicated manner? I’m glad I was never exposed to a “learning accessory” like this one when I was a child. It would have brought out my inner Chucky if I was faced with the choice. Whether I approach “science communicators” on The Skeptic’s Guide to the Universe, High School teachers, scientists, engineers, or other educators, there is a virtual eye roll, and a sanctimonious dismissal tinged with “I already know all about the metric system” or worse, the assertion that “it doesn’t matter what system of measure one uses.” I would like to think that most educators are interested in teaching and not simply parroting, but at this point it looks like “Polly want’s a hectometer.”


If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

The Battery of Batteries

MINOLTA DIGITAL CAMERA

By The Metric Maven

Bulldog Edition

When I first discovered batteries as a young boy, I was fascinated, but this feeling would soon turn to disappointment. I had small flashlights, and small toy cars that would quickly drain the batteries, and then the fun was over. I had no way to obtain new batteries, but my father purchased a “home battery charger.” It could hold batteries from AA to D and when they were done “recharging” a neon light would shut off. I very quickly discovered  that “recharged” batteries would discharge at such a fast rate that it was almost a waste of time to charge them. I cut open dry cells and other batteries to see what was inside until my curiosity was satisfied.

Willard-Storage-Batteries-1925-Clean
1925 Advertisement for batteries

I encountered batteries again when I was studying for my Professional Engineering (PE) exam. What I learned was there are two kinds of batteries. The first type of batteries are single use. After they have been discharged they cannot be recharged. These are called a primary cells. Primary cells undergo a chemical change which is not reversible. The second type are those that are chemically reversible, and rechargeable. These batteries are called secondary cells. The number of times a secondary cell can be recharged is finite. My PE reference states that:

The cycle life is the number of times a battery can be discharged or charged before the output voltage drops to a prescribed value. A cycle is a predetermined number of amp-hours (A*h) of discharge or charge.

When I first encountered the idea of ampere-hours (amp-hours?–tsk—tsk) it seemed to make sense. I found it quite interesting that primary cells had a lower “service capacity” depending upon the magnitude of current drawn from them:

PE-Reference

What this table does not reveal is the total energy extraction possible. To argue that mA*h is an energy term is misleading, this is an energy metaphor. In my view the best way to describe the total available energy in the battery would be in joules. Assuming these are all 1.5 volt cells, then in my view the table should have a third entry:

Energy Capacity (J)      Starting Drain Current (mA)         Service Capacity (h)
AAA

3132                                            2                                             290
2430                                          10                                              45
1840                                          20                                              17

AA

5670                                            3                                             350
3240                                          15                                              40
2430                                          30                                              15

C

11 610                                           5                                            430
13 500                                         25                                            100
10 800                                         50                                              40

D

27 000                                          10                                            500
28 350                                          50                                            105
24 300                                         100                                            45

One could argue whether the energy capacity should be the final column or the first. The energy values are all in the Kilojoule range, and so could have been written with decimal points to emphasize the magnitude more directly. In a previous blog we see that a common Subway sandwich is around 1000 Kilojoules (six inch sandwiches in Australia?—tsk–tsk–how about Subway “150 sandwiches”?). This provides some context for the energy involved.

One can immediately note that the total amount of energy one can extract from a AAA battery depends on how fast it is drained. One can give up about 41% of the available energy when extracting the energy at a 30 milliwatt rate (30 millijoules/second) versus a 3 milliwatt rate (3 millijoules/second).

The-Week
THE WEEK June 12, 2015 pg 32

Tesla Motors is a company founded by Elon Musk that offers electric cars for sale. Musk has also founded Solar City, and Space X. These companies, especially the last one, are championed as commercial, but the capital involved is largely provided by the public.

Perhaps the most important and costly component of an electric car is the battery. Electric cars were very popular in the early 20th century. Oliver Parker Fritchle (1874-1951) of Denver Colorado offered electric cars and wind power generation in this period. According to Wikipedia:

Fritchle achieved national celebrity for his 1908 Lincoln-to-New York endurance run in one of the first electric automobile models produced by his firm.[5] He covered the 1,800 miles (2,900 km) in a stock Victoria Phaeton achieving as many as 108 miles (174 km) between charges[6] through extremes in weather, terrain, and road conditions; a remarkable feat with an electric vehicle of that day. The trip journal and photographs subsequently published to promote The 100 Mile Fritchle Electric provided unique insight to the state of road and electric power infrastructure within the United States during the early twentieth century.[7]

Fritchle_milostat

Fritchle even designed brakes that reclaimed the lost kinetic energy and diverted it into the battery. His car achieved about 100 miles between charges with lead-acid batteries. An attached hydrometer indicated the amount of charge left in the battery. The Tesla Roadster achieves about 244 miles per charge with lithium-ion batteries.

Sven related that Johnny Carson once interviewed Maude Tull, who was a few years over 100 at the time, and Maude recalled how much she liked her electric car. Maude did not believe in charging the battery completely. She left it charged for about thirty miles or so in case someone stole it, they could not get far before the police would catch them.

While Fritchle did not dabble in solar energy in the early twentieth century, Sven pointed out that Edwin Cawston did, using it to power his Ostrich Farm. Aubrey Eneas was the man behind the harnessing of Golden State sunshine and started the Solar Motor Company in downtown Los Angeles. According to the LA Times:

Eneas installed the six-story high apparatus on a sunny hillside in 1901. The device, which resembled a radar dish, was 33 feet in diameter at its widest point and lined with 1,788 mirrors. The mirrors funneled the sun’s rays onto a boiler containing 1,000 gallons of water. The resulting steam was used to power an engine that pumped between 1,400 and 1,500 gallons of water a minute from a deep well on the farm. The dish was attached to a track on a supporting tower so it could be kept trained on the sun.

The monstrous magnifier only heightened the farm’s exotic quality. “No extra charge to see the Solar Motor!,” declared printed handbills. “The only machine of its kind in the world in daily operation! 15-horsepower engine worked by the heat of the sun!”

Solar_Power_Ostrich
1902 (SMU Libraries)

This introduction has been a prelude to discussing the “newfangled” Tesla Powerwall battery:

Tesla-millimeters

This battery is to be used to “Provide energy storage for a sustainable home.” There are two versions of this home battery, one has an “energy capacity” of 10 Kilowatt-hours and the other is 7 Kilowatt-hours. At least we are closer to describing energy than when using Ampere*hours. I must give Tesla some positive prose for giving the metric size of the battery in millimeters (1300 mm x 860 mm x 180 mm). These two values of “energy” in terms of energy are:

10 kWh (36 Megajoules)
7   kWh (25 Megajoules)

New Scientist May 9, 2015 (click to enlarge)
New Scientist May 9, 2015 (click to enlarge) Meet the new battery, same as the old battery.

In a previous blog I argued that using joules exclusively on energy bills would make them very transparent to consumers. I use both electricity and natural gas in my home. We will just look at my electricity usage for comparison. In the month I used as an example, my usage was about 3.2 Gigajoules of energy for the month. Assuming a 31 day month I use about 103 Megajoules of electrical energy per day or 4.3 Megajoules per hour. This battery would provide my home with just over eight hours of power. This amount of energy is large enough to make it through many power outages, but it is not any type of panacea for the storage of solar energy. A more thorough examination of the Tesla Power Wall has been undertaken by Dan Steingart and may be found here.

The larger point, once again, is that it seems reasonable to use energy to describe energy (joules), and energy flow to describe energy flow (watt = joule/second). People do not describe public water towers in terms of Kiloliter-hours of water, they (if they are refined persons who use the metric system) would describe the water tower capacity in Kiloliters period (2000 Kiloliters for the largest spherical water tower in the US).

The joule, when used appropriately, describes the amount of energy in a sandwich, a battery, my monthly electrical usage, or even the energy of an asteroid strike. The June 2015 issue of Astronomy magazine has an article by Eric Betz entitled To Catch a Shooting Star. This article includes a very nice NASA map of asteroid/meteorite impacts and their associated energy in Gigajoules:

Asteroids-Joules
(The energy use of a typical household is probably about 1-10 GJ per month.)

We have an excellent unit of energy that can be used for universal comparison, the joule, it’s just too bad we want to describe our energy in metaphors that masquerade as numerical information, rather than just presenting numerical information and informing ourselves and the public.


If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.