Technology Index

The Perversity of Inanimate Objects 1 4/10/10
Insulin Pumps 5/20/10
Wars With Word 5/28/10
The Perversity of Inanimate Objects 2 6/4/10
Float Chair (fictional) 6/24/10
Tricycles are not Bicycles 8/8/10
Why Temperature Remembered doesn’t match the Record 4/5/11
Does Banking Software Work? 4/21/11
My New Toy – an iPad 2 5/12/11
Before Computers 6/5/11
How do you Eat a Salad? 4/28/12
Battery Woes 5/12/12
Printer Woes 6/14/12
Adult Proof 9/8/12
Digital Cameras 9/29/12
Who Needs a Nightcap? 9/3/13

Why an Index?

With 550 posts as of today, I’ve started to have problems remembering what I’ve already put on here. This is particularly a problem with posting existing content such as poems, short pieces from the Summer Arts Festival, or science explanations originally written for the Alaska Science Forum. I can’t remember which books or DVDs I’ve posted reviews on. It also is starting to be a problem when I want to link to a previous post and can’t remember when it was put up or what the title was. And there are posts on this blog that have permanent information, like the series on planet building and the one on horse color genetics, or the book and DVD reviews. I want to make it easier for my readers as well as myself to find things.

I made a start some time ago by adding an index page, which can be accessed from the menu at the top of any page. Right now, the only links are to index pages on my author site. This takes you out of the site and sometimes back in, which is rather clumsy. The index list is also incomplete.

I’m going to start posting an occasional entry which is strictly an index of past posts on a particular topic. These posts will be linked from the index page, and will link forward to the individual blog posts. As it takes a while to find all the posts that belong together, this will be a slow process—probably extending over the next few months. The first in this series, on DVD reviews, is already queued for January 3. Others will follow, most on Thursdays.

I probably won’t be indexing every post. Some, like those early posts which were simply glossary entries for my books, are on the author site and really belong there. Others, like the regular Monday updates on North Pole weather starting in November 2010, can be found easily enough just by using the calendar on the site. But I hope that by the time I have finished this, older posts of interest will be easier to find.

Tricycles are Not Bicycles

That’s adult tricycles, of course.

You may think that, having ridden bicycles for years, riding a tricycle would be a no-brainer. But remember when you made the transition from tricycle to bicycle, probably with the aid of training wheels? At first you probably felt pretty unstable—three points on the ground keeps you level; two doesn’t. But at some point you discovered that if you leaned one way or the other the bicycle turned in that direction rather than falling over, and that fact rather quickly got into your muscle memory. Without even being consciously aware of it, you began to rely on weight shifts, rather than the handlebars, for steering.

The reason a bicycle reacts that way is conservation of angular momentum. I’m not even going to try to explain it (it takes calculus) but if you’ve ever taken a physics class you’ve probably seen it demonstrated. A student sits on a revolving chair holding a spinning bicycle wheel. If he tries to change the direction of the axis of the wheel, he will turn himself. A spinning bicycle wheel on a bicycle acts exactly the same way. Its axis tries to stay pointing in the same direction, which keeps the bicycle upright. If you force the axis to move, by shifting your weight, the result will be a rotational force at right angles to the force you put on the axis. Leaning tries to tip the axis vertically; the turn forced is horizontal.

Of course a bicycle does try to tip over if it is stopped—if the wheels aren’t turning. A wheel that is not spinning has no angular momentum—which is what makes the axis resist changing direction.

What happens if we apply the same principles to a tricycle?

I even rode my tricycle in the Golden Days parade one year, for a diabetes support group.

A tricycle touches the ground at three points, so it has no propensity to tip over while it is stationary on level ground. But that same three-point stability means that you cannot change the direction of the axis of a spinning wheel simply by shifting your weight. A tricycle has to be steered with the handlebars. Further, the front wheel will resist being turned, and if is turned too sharply when you are going fast, turning the wheel will try to tip the tricycle over. This isn’t usually a problem with a child’s tricycle, because most are direct-driven, with the pedals on the front wheel, and they don’t move very fast. My adult tricycle is a three-speed that easily exceeds 10 mph on a slight downward slope.

Even worse, if you are riding on level ground and hit a side slope, the tricycle will try to turn of its own accord. This leads to real problems with uneven ground, side slopes, and angled curb cuts on bike paths, especially since a tricycle with a rider is very top-heavy.

A tricycle is a bicycle legally, so I can ride on bike paths. I tend to avoid narrow shoulders, for obvious reasons—first because a tricycle is a good deal wider than a bike, and second because most roads are crowned. This means I am riding on a side slope where I must steer very accurately to avoid getting one of the rear side wheels off the pavement. It’s also rather miserable to “walk” a tricycle–the rear wheels keep hitting you in the back of the leg

In short, a tricycle takes some retraining of your reflexes if you are used to riding a bicycle. They are still wonderful exercise for someone like me who no longer has the balance to ride a bicycle.