Which laptop is best for losing weight?
by John Lansdale

I started to write an article titled "Power Is Out". I was going to hypothesize a billion computer geeks like myself using a computer as much as I do for the next fifty years and compare. In these times of energy crisis, would there be enough power for all of us or would we have to fight? I'd get my facts from the Wikipedia Orders of Magnitude (Energy) page. Smugly, I presumed in this test of sustainability my own cool little Asus Eee or XO1, would use so little energy compared to the older laptops that it would reign supreme. I was surprised by the result. Actually, the world has enough energy to power either. As computing goes, power won't be out. A discovery made while researching proved more interesting.

To do the analysis, I had to first gather all the energy variables and convert to a common unit of measurement. The International Standard of Units or SI for energy is the joule. Energy is power over time. The power SI we understand (and can look up reference to on the backs of transformers, electric bills, etc.) is the Watt which equals Amps x Volts. One watt hour is 3600 joules.

Ten watts was a good assumption for the low energy laptop. It"s the average for either the Asus Eee or OLPC XO. For high energy, one hundred is about what an older laptop or a smaller energy efficient small workstation would use. A good serious use for each user would be fifty weeks per year forty hours a day (at the computer) for 2,000 hours per year.

A few terms need to be clarified. Order of magnitude" is just an easy way of understanding big numbers. Numbers are changed to scientific notation and listed smallest to largest. They're split into two parts which, multiplied together, give something close to the original. One is a decimal number usually with just one or two places so it's easy to read. The other is the power 10 must be raised to in order make the number come out right. For example the national debt estimated at $9,451,094,214,451 in order of magnitude terms is 9.45 * 10 ^ 12 or since that much precision isn't needed for comparison of numbers this large 9.5 * 10 ^ 12 is good enough. Another way of writing it is 9.5E+12. In computer lingo "*" means multiply or "x" and "^" means raised to the power of or raised-to. I use the term interpolate somewhat loosely but you'll see it best expresses the idea. In mathematics interpolation is a method of constructing new data points within the range of a discrete set of known data points.

Figure 1. Google calc automatically calculates numbers and translates units.

There are other factors to consider. Energy can’t just be converted between forms, transmitted and stored without sometimes large losses mandated by the laws of physics. Also, computer speed is directly related to power. There is little way around this. One of these is to replace slow startup hard disk drives with solid sate drives. Software efficiency is another. Over time though, restraining speed limits functionality so this example assumes little hardware innovation. Even so, looking at numbers this way helps set limits and best and worst cases.

Scenario 1. Brave New World: A billion computer geeks using high power laptops.
Average power (watts) = 100
Hours per year = 2000
Users = 1 billion (10 ^ 9)
One watt hour = 3600 Joules
Energy requirement = 100 * 2000 * 10 ^ 9 * 3600 = 7.2* 10^17 Joules

Scenario 2. Brave New World Improved: Same as above, using low energy laptop
Average power (watts) = 10
Energy requirement = 10 * 2000 * 10 ^ 9 * 3600 = 7.2* 10^16 Joules
Interpolate with other energy magnitudes and compare. A few extra numbers are included for perspective. Note. My calculated data is bolded, Wikipedia data isn’t.

7.2 * 10^10 J, the energy consumed by the average U.S. automobile in the year 2000
7.2 * 10^16 J, 1 billion geeks using low energy laptops
7.2 * 10^17 J, 1 billion geeks using high energy laptops
7.2 * 10^17 J, energy consumed by 10 million automobiles
3.6 * 10^19 J, 1 billion geeks using high power laptops for the next 50 years
6.25 * 10^19 J, the yearly electricity generation of the world as of 2005
8.01 * 10^20 J, Estimated global uranium resources for generating electricity 2005.
3.9 * 10^22 J, the estimated energy contained in the world's fossil fuel reserves as of 2003

You can see my presumption was wrong. Laptops, environmental or not, won't put much strain on the world's resources. If anything automobiles are the problem, and while it looks like there's plenty of nuclear power for laptops, there isn't much compared to the amount automobiles use!

Another number in the “order of magnitude” table really caught my eye. By generating power ourselves for our laptops with a hand crank or bicycle generator device or something we could lose weight. It is 4186 Joules = 1 Calorie (or kcal, commonly used for food, not to be confused with “calorie”).

Scenario 3. Brain New World: Exercise per day charging a low power laptop with a mechanical device.

Power to charge (watts) = 20
Hours = 4
Users (me) = 1
One watt hour = 3600 Joules
Energy requirement burned in a day = 20 * 4 * 1 * 3600 = 2.88 * 10 ^ 5 Joules or 69 Calories

Some more magnitude numbers from the low end of the Wikipedia list are needed.

1.7*10^4 J, the energy released by the metabolism of one gram of sugar or protein
3.8*10^4 J, the energy released by the metabolism of one gram of fat
5.0*10^4 J, the energy released by the combustion of one gram of gasoline
7.2x10^5 J, the energy used to charge a low energy laptop
6.3*10^6 J, the recommended nutritional intake per day for a woman not doing heavy labor
8.4*10^6 J, the recommended nutritional intake for a man

My final and most significant discovery came from Wikipedia Orders of Magnitude (power) All this calculation can be avoided. Time is the real enemy of weight loss. Small improvement over long periods is most effective. Thinking (not so much the Calories but the lessons) fits this category. Both fears of world energy Armageddon and high cholesterol can be assuaged by increased thought alone. The brain is the best laptop.

Scenario 4. Brain New World Improved: Thinking all day and night.

Approximate power consumption of the human brain (watts) = 20
Hours per day = 24
Users = 1
Energy burned in a day = 1.7 * 10^6 Joules or 413 Calories

Some nit-picker's have probably noticed a few flaws in this reasoning. For example, mechanically charging a laptop four hours a day only yields two of computing, in the electricity scenario there are eight. And, someone mechanically charging a laptop must also be thinking 24 hours .. or not which is my point. I’ve shown you a few tools, you’ve got a computer, and now it’s your turn.




Click Here


DacsGear!
Mugs and more, visit CafePress to order

 

 
 
© Danbury Area Computer Society, Inc. All Rights Reserved.
Web Site Terms & Conditions of Use