Archer’s Big Bounce Experiment
I am a big fan of University of Minnesota Athletics—even more so now after they sponsored a Science of Basketball project for grade schoolers. My 9-year-old grandson Archer jumped at the chance to put a variety of basketballs to the test with my help. For the results, see the video we submitted to the UMn judges.
Archer’s findings–wood being better than rubber for bounce–stand out in graphics generated with Design-Expert software.
Archer enjoyed doing this science project. I feel sure it helped him understand what it takes to design an experiment, do it properly and analyze the result. My only disappointment is that the high-tech cell-phone app for measuring height, which I used for my experiment on elastic spheres, failed due to too much echo in the gym, most likely.
However, I discovered another intriguing basketball-physics experiment at the Science Buddies STEM website. It determines where a bouncing ball’s energy goes . This requires deployment of an infrared-temperature gun with a laser beam. Awesome! Archer will like that (if he can wrestle the laser gun away from me).
Groundhog Day: Looking forward to spring and the arrival of robins
Puxatawney Phil saw his shadow this morning, thus forecasting 6 more weeks of winter. Most people in the USA took this as a bad sign that spring will not come early—the prediction when Phil does not see his shadow. However, we hardy Minnesotans do not mind 6 more weeks of winter whatsoever.
A sure sign of spring comes with the sighting of the first robin in my yard—typically later than Phil’s more pessimistic forecast. I looked for statistics on the annual migration of robins from the USA National Phenology Network but, though this bird is their most frequently observed animal with over 190,000 records, nothing came up readily on dates of first sightings in my region of the country.
In any case, I will be very happy if the robins do beat the 6-week forecast for spring as they did in 1996 per this report—arriving in Minneapolis on March 12th of that year. Until then, I can only enjoy this lovely video of American robins produced by Lesley the Bird Nerd who grew up north in Ontario—the next stop in the bird’s spring migration after Minnesota.
What got me thinking so early in the year about robins was a report in the Royal Society last week on “The limits of egg recognition: testing acceptance thresholds of American robins in response to decreasingly egg-shaped objects in the nest”. Check out the bizarre fakes—robin-egg blue, of course—pictured here . Evidently it’s not the shape that matters, for example, a pointy eight-sided egg stayed in the nest, but, rather, the size. Those that looked big enough to be put in by a cowbird, a parasitic species, got tossed out. The robins also rejected eggs that were too thin.
“They seem to be quite hesitant about rejecting eggs when the variable that we changed was not natural,” Dr. Hauber said, referring to the angular, pointed eggs. “Robins don’t know what to do with it, because they’ve never evolved to respond to it.”
Quote reported by New York Times in their interview of lead-author Mark Hauber, a professor of animal behavior at the University of Illinois, Urbana-Champaign.
I am tempted to dig up the collection of Dungeons and Dragons dice left behind by my two sons after they moved out and put them out in the bird house this spring to see what happens. Just joking—I like robins too much to do anything so inhospitable. It is very weird, though, that they are so bird brained about egg shapes.
Killer reveals contents of International Shark Attack File
Posted by mark in Nature, Uncategorized on January 26, 2021
I will bet the caught your attention. It did mine but for reasons more benign than indicated by my sensational blog title: The report comes from an outdoors columnist for Florida’s Treasure Coast Newspapers named Ed Killer. He passed along the latest statistics on shark attacks released Monday by the Florida Museum on Natural History. It turns out that “interactions” with these dreaded aquatic carnivores decreased by nearly 10% to 129 worldwide in 2020. Unfortunately, deaths increased to 13, up by 2 from 2019, including the first ever in Maine. Australia led the world for shark fatalities and came in second to the USA for bites.
“When a surfer gets bit in New Smyrna Beach [Florida], it’s often by a blacktip and requires some stitches to recover from. But when a surfer gets bit in Australia, it’s by a 2000-pound 15-foot-long great white shark. A nibble from a white shark can take off a leg.”
– Gavin Naylor, Director, Florida Program for Shark Research*
All this talk about sharks makes me feel a lot better being homebound in Minnesota for the time being. In 1975 my wife and I moved to California just in time for the premier of Jaws at the local drive-in movie theater. I suffered twitchy-legged nightmares for some time afterwards imagining a great white shark lurking at the foot of my bed. Watching this Danish advertisement provides an antidote my now-revived shark fears.
*See details on the data science behind their The International Shark Attack File (ISAF), and a fascinating animated graphic showing attacks by location worldwide over 50 years, here.
Experiment reveals secret to maximizing microwave popcorn—Part two: Results
Posted by mark in pop, Uncategorized on January 3, 2021
Nothing beats microwave popcorn for snacking. That’s what makes unpopped kernels (UPK) so aggravating—not just for the loss of yummy yield, but also for the pain from accidentally biting down on them. Therefore, I am quite pleased to report significantly reduced UPK discovered by my designed experiment detailed in part 1 of this blog.
The big reveal comes from the interaction plot showing that the effect of preheating depends on the timing method.
First off, look up at the upper left of the graph and notice that the default GE timing, done by a humidity sensor, creates significantly greater UPKs—the lower end of the least significant difference (LSD) bars (p<0.5) fall above the higher ends of all other LSDs. The actual results using my GE microwave popcorn button, shown by the red (no preheat) and green (yes-preheat) circles on the left, ranged from 41 to 92—far too many UPKs per bag.
Next, see how the combination of GE++ (adding time) with no preheating wins out overall. The actual counts, shown by the red circles at middle bottom, ranged from 23 to 34—far fewer UPKs than before.
Life is good: Best not bother to put in 1 cup of water and wait for a minute; also, no complications introduced by setting up my cell phone, quieting the household, and standing by to turn off the microwave when alerted by Popcorn Expert. All I need to do is press the popcorn button and then 9 twice for the extra time. Easy! And, by the way, the popcorn tastes great—no burning!
I never would have made this significant improvement without the more-precise:
- measurement of UPK counts (versus weight) and
- Poisson-regression (versus ordinary least squares) modeling*
*(available in the newly released version 13 of Design-Expert® software)
I encourage you to do your own microwave popcorn experiment, ideally multifactor ones using Design-Expert version 13, now available as a free, fully functional, 14-day trial. Many factors can be tested—first and foremost being brand of popcorn and time in the microwave. Two ‘hacks’ posted to the question-and-answer website Quora intrigue me:
Another hack botched by me (as confessed in part 1) is pouring the popcorn into a vented microwave container. Throw one or more of these factors into your design of experiment (DOE) and please let me know the statistical outcome along with the raw data.
I remain a few dozen kernels short of the perfect microwave popcorn: Zero UPK with every exploded morsel being incredibly delicious.
Every once in a while, someone will mail me a single popcorn kernel that didn’t pop. I’ll get out a fresh kernel, tape it to a piece of paper and mail it back to them.
Orville Redenbacher
Experiment reveals secret to maximizing microwave popcorn—Part one: Setup
Posted by mark in design of experiments, Uncategorized on December 27, 2020
Energized by a new tool in Design-Expert® software (DX) for modeling counts (to be discussed in Part 2—Analysis of results), I laid out a design of experiment (DOE) aimed at reducing the number of unpopped kernels (UPK) from microwaved popcorn. I figured that counting the UPKs would be a far more precise measure of popcorn loss than weighing them, as done in this prior study by me and my son Hank).
My new experiment varied the following two factors in a replicated, full, multilevel, categorical design done with my General Electric (GE) Spacemaker microwave oven:
A. Preheat with 1 cup of water at 1 minute on high, No [L1] vs Yes [L2]
B. Timing, GE default [L1] vs GE++ [L2] vs Popcorn Expert app [L3]
I tested the preheating (factor A) before and found it to be unproductive. However, after seeing it on this list of microwave ‘hacks’, I decided to try again. Perhaps my more precise measuring of UPK might show preheating to be of some help after all.
The timing alternatives (factor B) came about when I discovered Popcorn Expert AI Cooking Assistant for systematically applying the #1 hack—the two-second rule: When this much time passes between pops, stop.
By the way, I also tried the third hack—pouring the popcorn into a covered glass bowl, but that failed completely—causing a very alarming “SENSOR ERROR”. It turns out that the GE Spacemaker uses humidity to determine when your popcorn is done. The plastic cover prevented moisture from escaping. Oops! Next time I try this it will be with a perforated lid.
While researching the user manual for the first time since buying the Spacemaker 15 years ago (engineers rarely read instructions) and learning about the humidity angle for the first time, I also found out that pressing 9 twice after beginning the popcorn cook added 20 and then 10 more seconds (++) at the end.
The original experiment-design of 12 runs (2×3 replicated) was laid out in a randomized recipe sheet by DX, all of them done using 3 ounce bags of Jolly Time, Simply Popped Sea Salt microwave popcorn. Due to a few mistakes by the machine operator (me) misreading the run sheet, two extra runs got added—no harm done: more being better for statistical power.
Part 2 of this two-part blog will delve into the analysis details, but it became readily apparent from a one-to-one comparison that the default popcorn setting of my GE microwave came up far short of Popcorn Expert for reducing UPK. However, the “++” adjustment closed the gap, as you will see.
To be continued…
New study reveals the benefits of being a bad wrapper
My wife Karen pulled a good trick on me this weekend. While surrounded with gifts for our very large family (now including 9 grandchildren), she asked “would you like to help me with wrapping?” Ha ha. At the beginning of our nearly half-century together, I taped comics from the Sunday paper around my gifts to her—pathetic but colorful. When Hallmark introduced handled gift bags in 1987, my presentation improved greatly with little effort required other than finding a suitable size and decor—thank goodness.
The ribbons! The wrappings! The tags! And the tinsel! The trimmings! The trappings!
Dr. Seuss
However, I may need to give wrapping another go after seeing this scientific study on gift wrapping that reveals why presents should look messy. It turns out that family and friends prefer sloppily wrapped gifts significantly more than those neatly trimmed. So it seems that my lack of talent in anything crafty is a strong point. Ha ha. (Last laugh.)
Cheers!
Genius dog challenges boggle the mind
Due to the social distancing necessitated by the current pandemic, dogs have become more valuable than ever for their devoted companionship. I have enjoyed owning a number of dogs throughout my life—observing a remarkable range in their intelligence, even within the same breeds. However, I doubt that even the smartest of my canines ever came close to six genius dogs now competing for this world championship in Budapest. They qualified by knowing the names of at least 10 objects. The winner, to be crowned later this month, will need to identify 12 toys with only a week of training.
This feat of memory and recognition seemed impressive by my meager experience with dogs (and limited talent for training them). However, it turns out that a Border Collie named Chaser, who passed away a year ago, knew over 1000 nouns. Incredible! In 2018, he and his owner and trainer, John Pilley, were put to a randomized test (with a surprising twist!) for PBS Nova by Neil deGrasse Tyson. Watch the 6-minute video: You will be amazed.
Raisin Bran sun wearing sunglasses and other shady “alternate memories”
Your mind plays many frustrating tricks. For example, as I detailed in How to arrest what’s-his-name’s [Ebbinghaus] forgetting curve, the brain purges valuable information far too quickly. A fellow statistical trainer recently refreshed my memory of the forgetting curve—citing this study that replicated the original experimental results from Ebbinghaus.
Coincidentally, I watched Friday’s episode of the quirky new “How to With John Wilson” HBO show*, which featured widely shared alternate (false!) memories such as:
- The Raisin Bran sun wearing sunglasses
- Stouffer’s Stove Top Stuffing mix
- Mandela dying in prison.
The last common misconception spawned a growing belief in what became known as the “Mandela Effect”. Check out this list with hundreds of other alternate memories and see if some resonate with your recollection. If so, you may be living in an alternate universe!
The “Mandela Effect” really plays tricks with your mind with memories that never happened but seem as if they did. However, it may not be evidence of a multiverse, but rather more mundane mental mistakes explained here by Healthline.
Never mind the Mandela Effect, the memory lapse that works for me is the forgetting curve—it doing its magic on the year of 2020.
“Forgetfulness is a form of freedom.”
― Kahlil Gibran
* Reviewed highly here by Vulture.
Moving averages creating coronavirus confusion
Posted by mark in Uncategorized, Wellness on October 26, 2020
The statistics being reported on Covid-19 keep pouring in—far too much information by my reckoning. Per the nation’s top infectious disease expert, Dr. Anthony Fauci, I focus on positivity rates as a predictor of the ups and down of the coronavirus. However, the calculations for even this one statistic cause a great deal of controversy, especially in times like now with rising cases of Covid-19.
For example, as reported by The Las Vegas Review-Journal last week, positivity rates for the Nevada now vary by an astounding five-fold range depending on the source of the statistics. It doesn’t help that the State went from 7-day to 14-day moving averages, thus dampening down an upsurge.
“We’re trying to get that trend to be as smooth as possible, so that an end user can look at it and really follow that line and understand what’s happening.”
State of Nevada Chief Biostatistician Kyra Morgan, Nevada changed how it measures COVID’s impact. Here’s why., The Las Vegas Review-Journal, 10/22/20
My preference is 7 days over 14 days, but, in any case, I would always like to see the raw data graphed along with the smoothed curves. The Georgia Rural Health Innovation Center provided an enlightening primer on moving averages this summer just as State Covid-19 cases spiked. Notice how the 7-day averaging takes out most of the noise in the data. The 14-day approach goes a bit too far in my opinion—blunting the spike at the end.
I advise that you pay attention to the nuances behind Covid-19 statistics, in particular the moving averages and how they get shifted from time to time.
PS My favorite method for smoothing is exponentially weighted moving averages. See it explained at this NIST Engineering Statistics Handbook post. It is quite easy to generate with a simple spreadsheet. With a smoothing constant of 0.2 (my preference) you get an averaging similar to a moving average of 5 periods, but it is far more responsive to more current results.
Twenty declared plenty: How slow will we go?
As reported earlier this week by the Center of the American Experiment, motorists face a new 20 mph speed limit in Minneapolis and St. Paul. City authorities figure on a significant reduction in neighborhood traffic fatalities, based on the statistic that a person hit at 35 mph is three times as likely to die as someone hit at 25 mph (they are reducing limits another 5 mph to 20 mph out of an abundance of caution, presumably). Prior to a new law that came into effect a year ago, the Minnesota Department of Transportation (MnDOT) set speed limits based on engineering and traffic studies. But now cities need not involve MnDOT when setting traffic laws for residential streets.*
The lowering of speed limits in the Twin Cities follows a trend in USA metro areas from coast to coast as evidenced by this Seattle Department of Transportation post last December (check out the animated graphic showing how a person’s chance of surviving being hit by a car decreases drastically with faster speeds).
My thoughts:
- If 20 mph on residential streets got enforced, that would be a relief for those like me with young children at home (grandchildren in my case). However, I doubt this will happen, especially with cutbacks in police after the troubles in Minneapolis earlier this year. The lower limits will only work with plentiful speed bumps (more appropriately known as “sleeping policemen” in UK).
- Being an engineer, I worry about taking experts on traffic safety out of the loop in favor of politicians making sweeping edicts with no regard for varying factors for individual streets.
- What are the economic trade-offs of the added time needed to travel at slower speeds versus the increased safety? Is 20 mph optimal?
“Typically, drivers travel 8 to 10 mph above the posted speed limit with a perception that the posted speed limit is a minimum, not a maximum [and] when the posted speed limit is reduced, drivers do not obey the new limit or even pay attention to it unless there is significant enforcement.”
Research Brief: Review of Current Practices for Setting Posted Speed Limits, April 2019, AAA Foundation for Traffic Safety.
One thing for sure, I find it excruciating to drive at 20 mph for any distance. The seems to slow to me.
*Focus on New Laws: Cities Authorized to Set Certain Speed Limits, July 22, 2019, League of Minnesota Cities.