429. Scales, digital and ridiculous

Ah, the good old days. They really sucked.

Even the phrase sucked falls into that category. I know that most of those who read this will not remember, but there was a time when nobody said sucked. It ranked up there with the “F” word. I remember when it arrived on the scene in my middle school students’ vocabularies, how it was an issue for a short time, and how two years later teachers were saying it. That’s what happens when a perfectly good forbidden word becomes common; it loses its flavor.

============

I have a great respect for Science Olympiad, but I never liked coaching, so I always volunteered to judge events instead. I enjoyed taking on new events that needed to be shepherded through their first year of implementation, and that led me to build a lot of gadgets to use in judging the contestants’ gadgets.

The people who think up new events in Science Olympiad often show an Olympian detachment (pun intended) from reality. Case in point — and forgive me if my numbers are off, I’m writing from memory — in two events students had to build light structures and test them to destruction. First it was a bridge, and a few years later, a tower. The lightest bridge or tower that held the most weight before failing won the event. There was a formula for weight vs. load, and specifications for what constituted failure.

The students applied the weight by pouring sand into a suspended bucket and there was a set maximum. If the structure held the maximum, the lightest structure won. If the structure failed, the weight vs. load formula was invoked. All in all, it was a well thought out event.

Except for one thing. The load was in pounds — up to ten, as I remember — and the weight of the structure was in grams. Let’s do the conversion.

1 pound equals 16 ounces
1 ounce equals 28.35 grams
Therefore, 10 pounds equals 4536 grams
And 9 pounds equals 4082.4 grams
That is a difference of 453.6 grams

Did I lose you? Just look at the cartoon at the top for a moment, regain your equilibrium, and come back to me. There is no final exam on this. This is just memoir about how much fun teaching science can be on a small budget.

To measure mass in grams, you could use a triple beam balance available in any science class. To measure ten pounds, you have your bathroom scale. But wait a minute, that ten pound maximum-weight bucket of sand has to be measured in grams! How do you do that?

You do it with levers, using the gizmo pictured at the top of the page. I actually built it, and used it all the years I was associated with that event. The lever makes the scale read about 160 pounds when there are 10 pounds in the bucket. That spreads out the difference between two similar weights. The box the adult is staring at is my old Mac SE, with a preprogrammed formula in a database. The formula is:

Scale reading in pounds after the sand has been added (times) conversion factor to grams (minus) weight of bucket in grams ——- all this fed into the formula for comparing load in grams to weight of the bridge or tower in grams, a formula provided by Science Olympiad.

At the event, all I had to do was watch the contestant, and stop her/him at the moment the structure failed. He/she was only given ten pounds of sand to work with, so overfilling could not happen. I typed in the reading from the bathroom scale and the computer gave me the score — after I had built and tested the device, programmed the database, and provided ten pounds of sand, calculated to the nearest gram on the same device.

Fun? Of course it was fun. I volunteered to do this, remember?

Was it accurate? No and yes. No, there was too much friction for the gram readings to be accurate, but the friction was the same for every trial, so yes, the ranking of the contestants was completely reliable.

About three years after Science Olympiad retired the event, digital scales which would measure that much sand to the nearest gram became available for under five bucks at every-guy’s-public-man-cave, Harbor Freight. Thank goodness it didn’t come earlier and ruin my fun.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s