Category: Geekdom

When you’re a kid, those forty-five minutes of playtime before dinner feels like 15 years. Similarly, the 15 years between 30 and 45 feel like forty-five minutes.

It seems somewhat intuitive that since we have less experiences as youth that maybe time feels slower, decades later the information isn’t as new and exciting so perhaps life feels faster.

Jesse took this concept one step further. Assuming a 100 year life, he drew a curve 1/X where X is number of years old. While nothing fancy, the graph can be integrated to show the percentage of your life your next year is. For example, at birth 100% of your experiences are new, fresh data. Year two, the newness has a potency of 50%. By year fifty, your new experiences are dwarfed by the previous 49 and your life experiences account for only 2% of your knowledge base.

Jesse integrated under the curve for blocks of time representing 25 years. Here are his results! (click on the graph for full size)

How curiously depressing!

Today, just for kicks, I decided to take my temperature throughout the day and graph it. Over a 12 hour period I took 28 temperature readings. I figured this exercise would give me a control for when I do get sick and also provide some insight into how body temperatures change throughout the day. I took a temperature reading about twice an hour, though I didn’t do it on the clock so the data points are not perfectly spaced.

Researching the experiment before I started, I found the following graph on the American Psychological Association’s website. It shows a normal temperature expectation for a day person and a night person through a waking period.

37 Celsius = 98.6 Fahrenheit

Now, let’s see how my temperature scatter plot measures up to that norm

And now with a trendline

Analysis:

Average temperature: 97.14F (36.2C)
Lowest: 95.4F (35.2C)- 8:45am
Highest: 98.3F (36.8C)- 4:25pm

It should be noted that these temperatures resulted from a mostly sedentary Mike D. I’ll try and remember to bring my thermometer to Kung Fu tomorrow and see what happens to my temperature post workout.

A short while ago I was talking with Shamus about batteries. Specifically, Lithium Ion Batteries. Lithium Ion Batteries are everywhere (ipods, kindles, laptops, phones, etc.). and Shamus and I were debating the importance of letting a battery go dead before recharging. Was it necessary or harmful? Here are the two most important facts we learned:

#1. Keep it half-charged
#2. Keep it cool

Do not completely drain your batteries between charges. If you grew up with Nickle Cadmium batteries as I did, you might be familiar with the idea of battery memory. This is the tendency for batteries, if they are charged too often, to have unused cells that lose their potency.

Lithium Ion batteries don’t have this disadvantage. In fact, letting your lithium ion go dead regularly is not good for shelf life. Internet sources suggest that if the voltage of the battery drops too low you then the individual battery cells can reverse charge, causing permanent damage. That said, for digital devices that have a ‘fuel gauge,’ letting the battery go dead is the easiest means of re-calibrating that gauge so that it’s accurate. The general online consensus suggests letting your Lithium Ion battery drain completely about once every 30-50 cycles.

Inconveniently, if you keep it at 100% power you have loss of power as well. To quote Wikipedia:

high charge levels and elevated temperatures (whether resulting from charging or being ambient) hasten permanent capacity loss for lithium-ion batteries

Sadly, I searched around on the internet and could not find a real reason as to why this is. All the websites agree, but they also all quote one another. If anyone knows a battery expert, hook us up. We want credentials!

This chart from BatteryUniverse.com does a good job of summing up temperature and battery charge levels. Crazy!

For your laptop, the best way to get additional cycles out of it is to unplug the battery when the laptop is plugged in. That way, you’ll drop its active temperature and keep it from overcharging. For your ipod or phone, just let the charge dip to 10-20% before recharging, with a full recharge once every 30-50 cycles.

For these few disadvantages, Lithium Ion batteries have one of the best energy/weight ratios and are exceedingly popular. I hope some of these tips help you extend the life of your equipment.