Random Flukes

From time to time, in our day-in/day-out lives, stuff happens, that, at first glance, seem spooky or mysterious. Most often they turn out to be due to quite explainable phenomena. One of these events happened to me this week.

My 92 year old mother-in-law was being readied for heart bypass surgery. They would not permit her to wear her wedding ring in the operating room so she gave it to my wife for safekeeping. A few days later my wife cannot find it. It has been an anxious week and this upped the tension level.

She seemed to recall putting the ring in her coin purse but she could not find it there. Frazzled, she dumped the purse on the kitchen table and searched everything but found no ring. She remembered throwing out some tissues so all the trash was searched. Still no ring.

Being a retired engineer, I have been known to be “overly thorough”. I have actually been called anal-retentive at times. Sometimes this trait comes in handy.

I decided to carefully look through the coin purse. The photo shows what I saw. Can you see the ring?

[ Click coins to embigenate ]

The other examples of these everyday mysteries that I can recall are more technical.

One day many years ago while walking to my car after work, I heard a strange sound coming from the engine area of my friend’s car. I noticed a pile of shredded rubber under the front of the engine. It turned out that some unknown electrical fault caused the DC generator (this was before the days when alternators were used) to become a DC motor. The turning generator drive pulley shredded the rubber drive belt.

This last example may be hard to visualize but let’s give it a go.

I once owned a car in which I had added an air conditioner. In other words, it did not come with “factory air”. Such add-ons do not get the testing rigor of production automotive systems so glitches were not unexpected. One day the A/C failed and I traced the problem to a failed power switching relay. Examining the failed relay, I could not see a problem visually but voltage measured on the input terminal was not present on the other side of a riveted connection. How could there be an open circuit in a securely riveted connection? Hint: the relay base, where the terminal was riveted, was plastic.

The overheated terminal caused the plastic base to locally melt. Plastic flowed around the rivet and completely insulated it from the electrical terminal. When it cooled and the plastic solidified, current could not flow but the connection appeared firm to the casual observer.