Tuesday, May 13, 2008

A Pick-me-up

Can you say "Mechanical Advantage?" My kids sure can. Last Saturday at the Witte Museum in San Antonio, my kids had a great time at the "pulley" exhibit. Set up in a triad, children of all ages and sizes sit in a chair then proceed to pull themselves up into the air. The first chair used two pulleys (and was . . . blue? My son could tell you.) The second (green?) chair used three pulleys, giving the participant a greater mechanical advantage whereby they can more easily hoist themselves. The third, and final chair was red. Definitely red. Indubitably red. It had (guess how many pulleys . . . . yes), n+2, where n = 2. This was not only the apparatus which offered the greatest mechanical advantage, and therefore the easiest to use, but it was also red.

The red chair was a hit with my daughter. She must have spent 30 minutes on that seat. Trying to get her off was like trying to get a pork chop away from a hungry mama badger and her badger babies (have you ever tried that?) In the sport of "taking turns" or "looking at other exhibits at the museum" I was determined to oust her from that lift chair. The line of children with sore muscles from riding the more difficult chairs was getting increasingly longer behind me, inversely related to my patience and directly proportional to my daughter's resolve. At that point, I did what any good parent would do: I bribed her down.

Promising to build her one "just like it" at home (or at least something remotely similar and red, of course), she relinquished her throne with a small tear in her eye. "Crap!" I thought. "Now I've got to build a compound pulley system in the yard. I still owe her a spinning stool I promised to build after she wouldn't get off the rotating seat at Freddy's Custard the other night." It was going to be a busy week in the ol' workshop.

We eventually moved on to other exhibits, coming back to that red lift chair only two more times, and later went home, but not before stopping at the overpriced gift shop, very happy, content, and with a renewed appreciation for belts, pulleys, gravity, force, tension, coercion, and Wal-Mart prices.

On Sunday, gimpy legs and all (read previous blog), I took the family to Lowe's Home store to pick up a Mother's day gift, a birthday gift for my son, and to purchase some rope and pulleys. Looking a the wall of parts and more parts, I found several options for pulleys. The cheapest ones were plastic clothesline pulleys. Inexpensive but unsafe for what our purpose. The next gradation was for 5/16 inch rope rated at 150 pounds. With rope that thin, the kids would have a difficult time pulling themselves up. And of course, if I'm building something as cool as a personal hoist, I want to use it too! Weighing more than 150 pounds, I had to go up to the next size. A pulley rated at 400 pounds for use with 3/8 inch rope would do the trick, and since I would be needing 6, yes 6 of them (the museum, at only 4, has nothing on me), I passed on the next size (which was a $30 pulley rated at 700 pounds!)

When we got home, I thought the kids would be eager and excited to help me construct the new contraption, but they played their new DS games instead. I suddenly felt like the "Little Red Hen." Oh well, with the time and money and promises already invested, I've have to do it on my own. And so I toiled for an hour, after which I had a contrivance resembling something the great Leonardo Da Vinci could have built (if he lived near a Lowe's store.) With a proud display of my ever-growing Emotional Quotient, I deferred testing it myself and went inside to retrieve my daughter (who had already forgot about what I was doing outside for her.)

To make a long story short, I worked! We all took turns raising ourselves around 5 feet into the air, lower ourselves down, then lift ourselves up, then lower ourselves down . . . Lifting our bodies seemed to lift our spirits as well, at least until my daughter pointed out, "Daddy, why is the seat not read?"


Anonymous said...

Back to the drawing board...

Anonymous said...

At least now I know what you spent part of your weekend building a pulley seat/swing. I DID enjoy trying it out, sitting up high--almost felt like a child again. Is there anything you won't do for your little princess?.... Good answer.

Anonymous said...

That first sentence should have read - WHY you spend part of your weekend, etc. It never pays to be in a hurry.