Shala K. Howell's Blog, page 18

A selection of vintage Ford cars

Earlier this summer, we happened across a line of vintage cars parked on a street next to a town festival in Northern California.

Naturally I took pictures. Turns out, even though there were lots of vintage Jaguars and Dodges there as well, almost all the pictures I took were of various types of vintage Fords. (Did that man know how to market to the average American or what?)

Two early Model T’s

Sadly, my vacation brain forgot to make sure that I also took pictures of the signs saying what each car was, but I’m pretty sure this one’s an early Model T.

[image error]Oh my goodness, would you look at that hand crank. (Photo: Shala Howell)

Different car, but miraculously I included the sign in one of the photos. Which is why I can say with confidence that this is a 1913 Model T. According to the sign, it was manufactured on January 17, 1913.

[image error]I can’t decide which part of this picture I like the best: the hand crank, the guitar in the back seat, or the man with the fedora. Is this the most Californian thing ever? I don’t know, but it’s a contender. (Photo: Shala Howell)



A 1926 Model T modified for racing with a RAJO overhead valve

Next up, a 1926 Model T modified to perform on the car racing circuit. You may remember this car from my July 4th post. At the time, I didn’t know what a RAJO overhead valve was. Apparently, it was a special valve designed by former car racer Joseph W. Jagersberger and manufactured in Racine, Wisconsin that was designed to increase the horsepower in the standard Model T Engine.

The good folks over at the Old Motors blog explained that adding the RAJO overhead valve to a standard Model T engine could boost the engine’s power from 20 h.p to 30 h.p. Contemporary advertisers claimed that Model T’s equipped with the RAJO overhead valve could go from 0 to 70 mph in just 600 feet. (The Old Motors blog has some great contemporary photographs and ads at their place if you’re interested in that sort of thing.)

[image error]1926 Model T modified for racing. (Photo: Shala Howell)



A Model A roadster for variety

This picture actually included the sign. Sadly, the date on it was obscured by the windshield wiper.

[image error]Model A Roadster. (Photo: Shala Howell)



A Ford De Luxe (probably)

Let’s end this post with what I think is a Ford De Luxe. Ford introduced the De Luxe in the late 1930s to offer customers a slightly better than standard car, at a price point lower than the higher-priced luxury models in its Lincoln car line. I had seen Model T’s and Model A’s in person before, of course, but I think this is the first time I’ve encountered a Ford De Luxe in the wild.

[image error]Ford De Luxe at a recent vintage car show in Northern California. (Photo: Shala Howell)

(If only I’d thought to take a picture of its sign so I could be certain what I was looking at. I’m relying on an identification by Google image search here.)

What about you? Have you stumbled across any interesting vintage cars this season?

Related Links:

Twin-Engined Model T Ford Monstrosity with Rajo Heads (The Old Motors)Happy 4th of July (Caterpickles)

Wordless Wednesday: Bougainvillea

It’s just a glorious time of year for flowering plants. Google tells me this is a bougainvillea.

[image error]Photo: Shala Howell

Oh, by the way, Happy (slightly early) 4th of the July, y’all.

Related Links:

More Wordless Wednesdays on Caterpickles

Happy 4th of July!

Just a quick post to wish you and yours a very happy 4th of July, and to thank you for making Caterpickles a part of your day.

We’re going to take a few days off here at Caterpickles Central to enjoy the summer and maybe learn a few things about vintage cars. ‘Tis the season for vintage cars, after all.

Here’s a photo of a 1926 Ford Model T Speedster modified for racing. We spotted it at a recent Vintage Car Festival in our area. Regular readers will remember that one of Roland T. Byrd’s crew member showed up for a dig in a Model T. I’m going to go out on a limb here and declare that it probably wasn’t a racing model.

[image error]1926 Ford Model T Speedster. The little sign on its front told us that the original Model T body had been replaced with a lighter weight body suitable for racing. Also that “a RAJO overhead valve was added for extra power,” which raises the question: “What’s a RAJO overhead valve?” (Photo: Shala Howell)

Related Links:

More Wordless Wednesdays on CaterpicklesShala reads books and counts OSHA violations: The Bones for Barnum Brown edition (Caterpickles)

Wordless Wednesday: Obligatory summer caterpillar post

It’s not summer if I don’t have at least one post with a bug.

[image error]Google tells me this is most likely a Western Tussock Moth caterpillar. (Photo: Michael Howell)

Related Links:

More Wordless Wednesdays on CaterpicklesMore summer bug posts on Caterpickles

Book Review: What the Night Sings by Vesper Stamper

What the Night Sings by Vesper Stamper

Knopf Books for Young Readers, 2018 
Age Range: Grade 7 and up
Format: Print, Library Bound

From the Amazon Book Description: 

“After losing her family and everything she knew in the Nazi concentration camps, Gerta is finally liberated, only to find herself completely alone. Without her papa, her music, or even her true identity, she must move past the task of surviving and on to living her life. In the displaced persons camp where she is staying, Gerta meets Lev, a fellow teen survivor who she just might be falling for, despite her feelings for someone else. With a newfound Jewish identity she never knew she had, and a return to the life of music she thought she lost forever, Gerta must choose how to build a new future.”

What I Thought

I’ll be honest: When the librarian at my daughter’s middle school handed me this book at the end of May with a strong READ THIS NOW recommendation, I wasn’t sure I’d be able to handle it emotionally. And frankly it was touch and go there for a bit. I read most of it in two giant gulps, but they occurred a couple of weeks apart. I needed the emotional break.

[image error]

When the book opens, the main character, Gerta, has no idea she is even Jewish. She lives with her father and her stepmother in Germany. Her father is an accomplished musician, and Gerta spends all of her time practicing the violin with her father and training with her stepmother for her upcoming vocal debut.

Before that debut can take place, however, someone turns Gerta and her father in to the Nazis. Her father tells Gerta that she is Jewish while they are on the train to the concentration camp. Although Stamper does include some of Gerta’s experiences at the camp, the bulk of the book deals with life in the camp after liberation.

This may be the only book I’ve read about the Holocaust that deals primarily with the question of what happens after. How do you rebuild your life after all you thought you had has been systematically stripped away both by the people who imprisoned you and the things you had to do to survive while so many others died?  

As Stamper’s vivid illustrations and skilled storytelling make clear, liberation is a much more complicated process for both the former prisoners and their liberators than most history books lead us to believe. After liberation, it takes months to refeed and revive the former prisoners enough for them to even imagine restarting their lives. And in the meantime, life in the camp remains extremely difficult, even when that camp is run by benevolent, well-intentioned people with the express goal of nurturing the people housed there.

Thankfully, Stamper’s narrative ends on a hopeful note. So yes, even though it’s hard, if you pick up this book, do yourself the favor of reading through to the end. This book is essential reading for our times.

Who Would Enjoy This Book



Anyone looking for a fictionalized account dealing with the aftermath of WWII or the founding of Israel

Wordless Wednesday: Silk Tree

While touring the Happy Hollow Park and Zoo in San Jose, CA, The Twelve-Year-Old and I spotted a tree with a smattering of feathery pink flowers.

If my National Audubon Society Field Guide to Trees is to be believed, this is a silk tree. Here’s a larger photo of the same tree.

[image error]Silk tree. (Photo: Shala Howell)

In case you are curious — Happy Hollow Park and Zoo is a cute little place, great for kids 10 and under, with a smattering of animals, some kiddie roller coasters, and lots of playground areas to just enjoy being outside. My daughter at 12 was just a tad too old for it, but we enjoyed seeing the animals anyway.

Related Links:

More Wordless Wednesdays on CaterpicklesHappy Hollow Park and Zoo, San Jose, CA

Shala reads books and starts counting OSHA violations: The Bones for Barnum Brown Edition

Regular readers know that I’ve been looking for a copy of Roland T. Bird’s 1944 essay, “Did Brontosaurus ever walk on land?” since 2011, when I had to rely on J.A. Wilson’s second-hand account of it while researching the answer to the pressing question: “Could sauropods swim?”

A few weeks ago, I discovered that I could have a copy of Roland T. Bird’s memoir, Bones for Barnum Brown: Adventures of a Dinosaur Hunter, delivered to my local public library through the Northern California Interlibrary Loan Service. So of course I did, hoping that it would include a reprint of his 1944 article, or at least a first hand account of how he found those Paluxy River trackways.

[image error]

Sadly, Bird’s account of his time on Barnum Brown’s dinosaur hunting crew, doesn’t explicitly include his 1944 essay. Still, Chapter 29 reads very much like Bird’s 1939 Natural History Magazine article, “Thunder in His Steps.” It’s almost word for word in places. So it’s possible that Bird may have recycled some of his 1944 article to write Chapters 32 through 35, which discuss–among other things–how the front-foot only trackways might have been made.

After searching for so long for source material that included Bird’s own account of finding and excavating the Paluxy River sauropod prints, I was a little surprised to find myself more interested in Bird’s rapidly deteriorating eleven-year-old Buick than in his excavation.

What did Bird drive while hunting for dinosaur fossils?

In Bones for Barnum Brown, Bird drives two main vehicles. The first was a Harley motorcycle equipped with a side camper. And when I say side camper, I mean camper. Bird had constructed a specially designed side car that folded out into a lovely little campsite for one or two people. Bird used the Harley to tour all 50 states before joining Brown’s crew, and for some of the early projects he did for Brown.

Bones for Barnum Brown includes a picture of the motorcycle camper. Probably because it was an unusual vehicle, even for the extremely practical and determinedly resourceful 1930s.

[image error]Image from Bones for Barnum Brown of Bird’s motorcycle camper set up for the night. The caption above the picture reads: “Bird and V. Theodore Schreiber with the Harley set up for camp, near Laredo, Texas.” (Source: Bones for Barnum Brown, p. 25.)

Sadly, the book doesn’t include any images of the aging Buick that Bird drives for his later expeditions for Barnum Brown, curator of the American Museum of Natural History in New York’s dinosaur collection. Most likely this was because at the time, the Buick was a fairly run-of-the-mill touring car, with no special features, aside from rust, to mark it as anything special. Even its age was unremarkable. Halfway through the book, Bird describes one of his crew members reporting for duty in a much older Model T.

Still, as far as I can tell from context clues, the car Bird used was most likely a 1927 or 1928 Buick touring car, with a canvas top, much like the one below, except in dark green and with more rust. The side curtains on Bird’s car were also apparently full of holes.

[image error]Restored 1927 Buick Touring car. (Photo by Vic Hughes via Creative Commons [CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0%5D)

I’d like to have seen it.

Over the course of the book, the Buick almost becomes a character in its own right. Here’s how Bird describes the car after it was hit by lightning on its final expedition.

“I stood looking at the Buick in the falling rain, thankful that she had not sheltered us from this particular downpour. Lightning was only a passing event in a life of many trials. Eleven years old, she had been driven so many miles and fleetingly dammed so many rivers it seemed foolish to throw away stuff as rare as money on her. If it had been practical, even at the start of this expedition, to replace the canvas of her touring top, to touch up or to repaint the light green body with its dark green trim and replace some of her more intimate parts, I should have done so. Now her very dilapidation set her apart and gave her color, even the rust spots. She symbolized all that went with fossil-gathering the hard way. If she continued to run and managed to last out the season, I should be satisfied and felt Barnum himself could ask no more of her. A gaping hole in the right rear corner of a long-ago jaunty touring top, where the canvas was blackened and charred by the bolt, marked the spot where it found metal.”

Roland T. Bird, Bones for Barnum Brown, p. 186.

One of my favorite things about reading this book is that it’s sprinkled with reminders that Bird lived in a very different time.

One of those reminders happened immediately after this paragraph. Fresh off feeling grateful that he hadn’t been sheltering in the Buick when it had been hit by lightning, Bird’s next action is to… wait for it… get into the Buick to wait out the rest of the storm.

“I got inside, out of the downpour. There was little shelter left under the remains of the top. A smaller hole than the new one poured water onto the leather back of the front seat. This lesser rent was memento of a sizable hailstone in Michigan, coming home from last year’s jaunt. I moved behind the steering wheel, the driest place I could find, and watched the rising storm lash the surface of the Paluxy like whips; in just a little while the restless stream would be booming with a fresh rise.”

Roland T. Bird, Bones for Barnum Brown, p 186.

Believe it or not, this is not the moment that made me start mentally counting OSHA violations. That event happened next.

Let’s count the OSHA violations, shall we?

Once the rain lets up a bit, Bird sensibly decides that he and his aging Buick had better get back to civilization before the Paluxy River floods out the roads. He calls to some nearby crew members to offer them a lift back to town.

Only problem? The car won’t start.

“Selecting, properly maintaining and routinely inspecting company vehicles is an important part of preventing crashes and related losses.”

Source: “Guidelines for Employers to Reduce Motor Vehicle Crashes,” US Department of Labor OSHA website

In retrospect, this was probably the first OSHA violation that led to all of the rest, but it wasn’t the one that initially caught my attention. After all, the Buick’s suboptimal condition had been a running theme since its first appearance in the book. I barely noticed it at this point.

No, the moment when I started counting OSHA violations was this one. After inspecting the car in the rain, Bird decides that the lightning strike has created a clot in the gas line. He removes the carburetor cap, siphons off a bottle’s worth of gas, and hands the gas and the siphon hose to one of his passengers.

“‘Elmer, if you ride the fender and dribble the gas to her, we’ll get you to Glen Rose just like I said. A little wetter than sitting under that hailstone hole, but …’

… And away we went. Elmer, wedged in behind the spare tire, did a great job. So did the old Buick. We rolled into Glen Rose as proud and happy as we were wet.”

Roland T. Bird, Bones for Barnum Brown, p. 186

That, my friends, is why I found myself counting OSHA violations in earnest in the middle of reading this book.

As far as I can tell (and I’m no OSHA expert), this episode violates modern OSHA Guidelines for Employers to Reduce Motor Vehicle Crashes in at least three ways.

The first one I’ve already mentioned. That old Buick was in dire need of some routine preventative maintenance. (1)

Of course, it turns out that OSHA has guidelines for seat belt use too. “Seat belts are the single most effective means of reducing deaths and serious injuries in traffic crashes.” Pretty sure Elmer wasn’t wearing one of those out there on that fender. (2)

And there are several paragraphs talking about distracted driving. According to the OSHA guidelines, “distracted driving is a factor in 25 to 30 percent of all traffic crashes.” Would having someone sit on your front fender siphoning gas into a lightning-convulsed engine while you drive count as a distraction? (3) 

Two other OSHA regulations might apply in this scenario as well.

The first is a “secure loose materials for transport” regulation. Technically, it applies to objects being transported in the passenger area of the car. But since its intent is to keep those materials from sliding around or becoming airborne during a crash or when the driver makes a sudden maneuver, I feel as though you could make a reasonable case that this regulation would have applied to Elmer as well, if OSHA had existed back then. (4)

The other is definitely a product of our time, and not Bird’s. Before employees take company vehicles out on the road, OSHA requires them to sign a driver agreement that commits them to follow specific safety policies while on the road. I know in my bones that Bird didn’t sign one of these. From everything I’ve read, it seems much more likely that Brown simply tossed Bird the keys to the Buick and told him to go deal with the Paluxy River excavation for him. (5)

Fortunately for Bird, but perhaps less fortunately for Elmer, OSHA didn’t exist until Richard M. Nixon signed the Occupational Health and Safety Act into law on December 29, 1970.

What I thought of the book, when I wasn’t distracted by OSHA

In general, Bird is a far better writer and his book much more fun to read than I had expected. Scientists have learned a lot about dinosaurs since Bird wrote this book, and it was pretty entertaining trying to figure out which tidbits were still correct and which had been amended as new discoveries had come in. For example, Bird very strongly believes that T. Rexes and other theropods couldn’t swim. New evidence suggests that yes, in fact, they probably could.

Never having been on a dig myself, I had also thought that it might be interesting to see what it would have been like to go on a dig in the 1930s, and I was not disappointed. The glimpses into what life was like back then were fascinating. Money was tight in those days, what with the Great Depression and all. The solutions Bird came up with to various obstacles on the dig seemed both ingeniously resourceful to me and second nature to him. His world was clearly not as disposable as ours has become.

[image error]Logo for the Sinclair Oil company (Source: Sinclair Oil website)

It was also a bit jarring to find that Sinclair Oil had funded most of Bird’s expeditions. It made sense, though. After all, Sinclair Oil still uses the sauropod in its logo. I guess back in the day, Sinclair Oil considered finding dinosaur bones to be great marketing for their fossil fuel company. (A quick glance at Sinclair Oil’s website shows that the company is still pretty invested in their entire dinosaur marketing scheme. Which makes me wonder if they still fund paleontology expeditions. A question for another time, I suppose.)

A final note: Bird’s book is definitely a product of his time. On the technology and dinosaur knowledge front, reading a paleontologist’s memoir about his work during the Great Depression can be a lot of fun. But when it comes to talking about people, well, let’s just say that a few times Bird describes the people around in him in terms that can most kindly be called dated. Those episodes were jarring for me. Thankfully they were also relatively infrequent.

Related Links:

“Could sauropods swim?” (Caterpickles)Update to a past Caterpickle: “Why did they draw that dinosaur underwater?” (Caterpickles) “Why does a book from 1999 still show a sauropod living in a swamp?” (Caterpickles)“Thunder in His Steps” by Roland T. Bird (Natural History Magazine archives)“A Dinosaur Walks Into the Museum” by Roland T. Bird (Natural History Magazine archives)

Wordless Wednesday: R.O.U.S.’s do exist

That R.O.U.S (rodent of unusual size) is a Capybara, the world’s largest rodent. We spotted him at the Happy Hollow Park and Zoo in San Jose, CA.

I would provide a 12-year-old for scale, but my daughter informed me that there was no way she was getting any closer to it. You will just have to believe me when I say this guy looked to us to be about as big as a medium-sized dog.

“You said ‘small pony’ when we were at the zoo, Mommyo.”

Small pony, medium-sized dog, whatever. The point is that this guy is larger than any rodent has any business being. Did I mention his teeth never stop growing?

[image error]Capybara at the Happy Hollow Park and Zoo in San Jose. (Photo: Shala Howell)

In case you are curious — Happy Hollow Park and Zoo is a cute little place, great for kids 10 and under, with a smattering of animals, some kiddie roller coasters, and lots of playground areas to just enjoy being outside. My daughter at 12 was just a tad too old for it, but we enjoyed seeing the animals anyway.

Related Links:

More Wordless Wednesdays on CaterpicklesHappy Hollow Park and Zoo, San Jose, CA

Wordless Wednesday: Today’s a writing day, right?

Look who showed up for work today.

[image error]That essay on top of my daughter’s desk, btw, is the one she wrote on the Mothman for Caterpickles. (Photo: Shala Howell)

Related Links:

More Wordless Wednesdays on CaterpicklesCaterpickles consults the 12-Year-Old: “What is the Mothman?” (Caterpickles)

“How much did that plastic bottle shrink in the dishwasher?”

This summer, I got my daughter a couple of high-volume plastic water bottles to use when she goes on adventures outside. I did try to switch the family to metal or glass water bottles, but my daughter never wants to take those outside, because they’re too nice.

The “Don’t worry about that. I’d rather you use it and destroy it than not use it at all” approach has completely failed. Meanwhile, summer is approaching, bringing with it the usual dose of warm weather and daughterly dehydration.

So when I saw some high-volume, inexpensive reusable plastic water bottles on sale at my local Safeway I bought a couple. Sadly, I didn’t notice they were also hand wash only until I got home.

Drudgery aside, those plastic water bottles were just what my daughter wanted.

My daughter totes them quite happily outside, and brings them back in with just enough dirt to convince me that she’s actually used them.

I wish I could claim that I had put the ruined purple one into the dishwasher for a good reason. I would love to say that my daughter had taken it outside and it had gotten so covered in mud and slime it would have been unusable without proper sanitation so I opted to run it through the dishwasher in lieu of dousing it in bleach.

But no. It was actually fairly clean. It shrank because I got lazy.

Our dishwasher has been broken for a couple of weeks, and after an eternity of hand-washing everything I was so thrilled to have a working dishwasher again, I just tossed everything in there. Even the stuff I knew I shouldn’t.

Whoops.

[image error]The shrunken purple bottle next to an undamaged blue one. At least the silver spots are more-or-less ok. I had been worried about them. The purple one is shown upside down because its new mushroom base is too wobbly. (Photo: Shala Howell)



Fortunately for me, shrinking plastic turns out to be a great at-home summer science project.

Which means I can turn this into a teachable moment that’s more meaningful than “Don’t put plastic in the dishwasher.”

I owe this insight to Wayne Goates at NSTA News. In 2002, he took the trouble of outlining a basic science project that parents can do with their kids at home to make shrinking plastic both fun and educational.

But before I get into the details of Goates’ experiment, and how I reworked it to suit our situation, let’s take a moment to learn why plastic shrinks when you heat it.

Why does some plastic shrink in the dishwasher?

I say some, because as you probably know from life experience, not all plastic shrinks in the dishwasher. Some of it just scratches up and gets cloudy, while other kinds of plastic don’t appear to be affected at all for quite a long time. Goates goes into much more detail about the why’s of this at his place, but I’m not going to here. I’m going to give you the very simplified explanation that I gave my daughter.

This particular type of plastic shrinks when heated because of the way it’s made. Basically, during the manufacturing process, a lump of this shrinkable plastic was heated, stretched into its water bottle shape, and held there while it cooled. Once cooled, the plastic had essentially frozen into the shape of a water bottle.

When you heat them again, these kinds of plastics have a tendency to go back to their original shape. How successful they will be at that depends on how hot they get, how evenly the heat is applied, and how long they stay hot. I don’t think my purple water bottle started life as a proto-water bottle with a mushroom base, for example. I suspect its new form may be more reflective of its awkward middle school years.

So how can we turn this unfortunate event into a summer science project?

Goates begins his version of this experiment by having his students carefully craft a metric ruler out of a plastic salad lid. He then heats the rulers in a toaster oven until they shrink. Students finish the experiment by measuring the shrunken ruler and calculating how much the plastic shrank and in which dimensions.

(There are several things to be careful about when shrinking plastic in a toaster oven, including setting your toaster oven too high, which can cause the melting plastic to release toxic gases, so I strongly recommend that you read Goates’ original experiment before trying this at home.)

I have a checkered history that includes setting every toaster oven I’ve ever touched on fire, so instead of making and melting Goates’ metric rulers, The Twelve-Year-Old and I just used the already shrunken water bottle and its not-yet-shrunken twin.

Since the two bottles were once the same size and shape, all The Twelve-Year-Old had to do was measure the height, radius, and volume capacity of both bottles. (Science!) Then she could use the numbers to calculate the amount of shrinkage. (Math!)

Step 1: Assemble the supplies.

For this experiment, we needed the before and after bottles, a measuring tape, pen, paper, and a calculator.

Step 2: Define your equations and terms.

My daughter had calculated the volumes of rectangular prisms and cubes in school, but not cylinders, so we looked up the formula for calculating the volume of a cylinder, V = πr2h, and wrote it down on our paper. I also broke down the formula into its component parts and made sure that she knew what each one meant (V is the volume, r is the radius of the base, and h is the height). We came to a Caterpickles agreement to use 3.14 for π to simplify things, even though that introduced some inaccuracies The Twelve-Year-Old wasn’t sure she wanted to live with.

We also talked about how we would calculate the shrinkage once we’d done all our measurements and volume calculations. In his example, Goates gives the formula:

[image error]

Modifying that to suit our situation gave us a formula that looked more like this:

[image error]

where [M] might be the height, radius, or volume.

This prompted a conversation about why we couldn’t simply divide purple’s measurement by blue’s and multiply that by 100 to get our answer.

My daughter pointed out that she did that calculation all the time when computing her grades at school, and it worked fine. “For example, Mommyo, if you get 18 questions out of 20 correct, that means you got a 90% on the test.”

That turned out to be a very helpful example, because it gave me a better way to explain what we were actually measuring in this experiment. When she calculated her grades at school, my daughter was measuring the percentage of things that were still there (the questions she had gotten right). In this experiment, we were interested in measuring what was missing. That meant, we were going to do the calculation she would use if she were trying to figure out what percentage of questions she had gotten wrong on the test instead of the ones she’d gotten right. It’s just that in this experiment, we would be measuring the height (or radius or volume) that was missing.

[image error](Inferior Graphic Design: Shala Howell)

Those explanations sorted, we were ready to start the experiment.

Step 3: Measure the height and radius of the two bottles, and use that to calculate the volume.

Goates’ experiment uses two-dimensional rulers, so he has his students measure length, width, and height. We’re working with three-dimensional cylinders (and former cylinders) here, so The Twelve-Year-Old measured the bottles’ height and radius, and then calculated their volume, using the formula V = πr2h.

[image error]Our data set at the end of this step.



Step 4: Calculate the shrinkage and its projected effect on volume.

Next, we calculated the shrinkage of the various dimensions using this basic formula:

[image error]



[image error]Our data set at the end of this step.



Step 5: Analyze our results.

We paused for a moment here to assess why we had gotten those particular results.

Why had the radius shrunk more than the height? Did that mean that the plastic shrank more in one direction than in another?

Maybe, but The Twelve-Year-Old thought it might actually have been a measurement problem. You see, she measured the widest point on both bottles to get the radius. On the purple bottle, that meant measuring the opening of the bottle. But on the blue bottle, that meant measuring the base. As you can see from the bottle pictures above, the opening was originally a smaller size than the base, so that very likely distorted the final results.

Why had the volume shrunk so much more than either the height or the radius?

The Twelve-Year-Old pointed out that the volume of the bottle depended on the height and the radius. Any shrinkage in those numbers would naturally be magnified in the volume.

Step 6: Compare our calculated volume for the purple bottle to its actual volume.



[image error]That water you see in the blue bottle is what we were able to fit in the purple bottle. I don’t know if you can tell from this photo, but the blue bottle is barely a quarter full. (Photo: Shala Howell)

There’s a lot of curl in the base of the purple bottle, and its sides are anything but straight. The equation we used to calculate the volume assumes that the radius remains constant throughout the entire shape. Our purple bottle’s radius obviously did not remain constant.

Although Goates’ experiment had stopped with the calculations, we decided that we wanted to know how close our calculated volume came to the melted cylinder’s actual capacity.

To test it, we filled the shrunken purple container with water. Then we poured the contents of the purple water bottle into the blue one. Then we calculated the volume of the water in the partially filled blue container.

[image error]Our data set after this step

I am certain that there must be a mathematical equation that can account for the volume differences generated by that mushroom base and the curvy sides, but for now, my daughter and I are content to know curves really matter when it comes to volume calculations.

Want to try this at home, without ruining your plastic cups first?

The science in our house may be accidental at best, but Wayne Goates is much more purposeful about it. He has instructions for a start-from-scratch science experiment that uses plastic salad lids cut into little rulers, in case you want to explore the science of plastic shrinkage with your kids (or students) on your own.

His write-up also includes much more detailed information on why the shrinkage happens the way it does, and some safety tips for folks who try this for themselves.

Related Links:

Shrinking Science (NSTA News)How to Calculate Volume (WikiHow)