15 July 2018

Our Model is BACK as Degenkolb Takes Stage 9!

After two stages of inexplicably slow cycling, during which our model came up short, we got back on track today.  Germany's John Degenkolb out-sprinted two Belgian cyclists, yellow-jersey wearer Greg Van Avermaet and Yves Lampaert.  Check out the finish below (click on image for a larger view).
Van Avermaet obviously keeps the yellow jersey through tomorrow's rest day.  I'm thrilled that our model did what it was supposed to do, especially with 15 cobblestone sections in today's stage.  An example of a cobblestone section is shown below (click on image for a larger view).
It's a good thing it wasn't raining.  Cobblestones can be dangerous, especially when wet.  Check out how our model performed today.
  • Stage 09:  3h 24' 26" (actual), 3h 27' 37" (prediction), 03' 11" slow (1.56% error)
I just LOVE it when predictions come in under 2%!

Tomorrow, Monday, 16 July, is the first of two rest days for the Tour de France cyclists.  They will rest in Annecy, which is in southeastern France, near the Swiss border.  The Alps await them!  Stage 10 begins on Tuesday in Annecy.  This first mountain stage ends in Le Grang-Bornand after 158.5 km (98.49 mi) of cycling.  Climbers will shine and the general classification will shake up.  There are three grueling category-1 climbs and one Hors catégorie climb.  The finish has a slight uphill, but that follows what is sure to be a fast downhill as cyclists descend from the top of Col de la Colombière.  Our prediction is given below.
  • Stage 10:  4h 15' 27" (prediction)
I can't wait to see the scenery and watch elite cyclists do their thing in the Alps!

14 July 2018

Groenewegen (Good!) and Our Model (Bad!) Go Back-to-Back

Dylan Groenewegen won his second straight Tour de France stage today.  And for the second straight day, I was watching the race and wondering when the pace was going to pick up.  Yesterday, a cyclist would leave the peloton, but nobody would follow.  The peloton looked just as sluggish again today.  The only exciting part of the stage was the final sprint.  Check out the screen capture I got (click on the image for a larger view).
André Greipel is in red and Fernando Gaviria is in blue in the back.  Peter Sagan is on the left in green.  Both Greipel and Gaviria got relegated by the judges after some head-butting.  Sagan ended up with yet another second place.

Our model should be relegated after today's stage!  We did worse than yesterday.
  • Stage 08:  4h 23' 36" (actual), 3h 59' 44" (prediction), 23' 52" fast (-9.05% error)
Groenewegen averaged a rather pedestrian 41.20 kph (25.60 mph).  The time schedule on the Tour de France's website had 44 kph as its slowest projection.  I'm sure there were fans along the route who were wondering when the bloody peloton was going to reach them!  Other than teams' strategies, I don't have a good explanation for the slow speeds over the past two stages.  When I watched yesterday, I'd see someone leave the peloton, but nobody would go after him.  Teams seemed content to go with the flow of the peloton.  We'd have to cut approximately 20% off our power to match the times of Stages 7 and 8.  There is no way we can know that at the start of the Tour de France!

I hope there is faster racing for tomorrow's Stage 9.  Taking place in the north of France, the 156.5-km (97.2-mi) flat stage begins in Arras Citadelle and ends in Roubaix near the Belgian border.  The stage is short compared to the last two and a rest day follows.  Surely teams will push more with the rest day coming.  Our model's prediction is given below.
  • Stage 09:  3h 27' 37" (prediction)
More than seeing my model come through, I want to see some fast cycling, despite the 15 sections of cobblestones!

13 July 2018

Groenewegen Wins Our Worst Stage

Dutch cyclist Dylan Groenewegen won today's long flat stage.   Despite crosswinds slowing riders down, I thought the stage would have been completed a lot faster.  I kept watching the race live, thinking, "Come on!  You're only averaging 38 kph!"  As if I could do any better, right?!?  I did get a screen capture when Groenewegen finally crossed the finish line, out-sprinting his competitors (click on image for a larger view).
Our worst prediction so far is revealed below.
  • Stage 07:  5h 43' 42" (actual), 5h 16' 33" (prediction), 27' 09" fast (-7.90% error)
There was time when I used to think if we got below 10%, our model was doing pretty well.  I no longer think that way.  I want to do better than 5%.  Groenewegen won with an average speed of 40.33 kph (25.06 mph).  Even the time schedule on the Tour de France website didn't think the average speed would be less than 42 kph.  Racing just looked slow today.  The peloton coasted much of the time, even when it got split.  Was the length of the stage a factor?  Were cyclists saving energy for the next couple flat stages?  I don't know.  Our model doesn't know about teams' strategies.  We've got to study this stage after the race ends!

Tomorrow's Stage 8 is another flat stage.  It begins in north-central France in the commune of Dreux.  Cyclists will ride 181 km (112 mi) mostly northeast to Amiens.  Our prediction is given below.
  • Stage 08:  3h 59' 44" (prediction)
Time to pick up the pace!  I want to see cyclists under four hours tomorrow.  I hope our model does a better job!

12 July 2018

Martin OWNS the Last KM!

Irishman Dan Martin simply owned his competition on the final kilometer of today's Tour de France stage.  He stayed in front of home-country favorite Pierre Latour during the final sprint.  I grabbed the screen capture below as Martin came upon the finish line (click on image for a larger view).
Some of the downhill racing hit speeds around 74 kph (46 mph).  There were strong headwinds and crosswinds near the finish.  Strategies and winds had me thinking our prediction might be a bit fast.  Below is how we did.
  • Stage 06:  4h 13' 43" (actual), 4h 06' 24" (prediction), 07' 19" fast (-2.88% error)
I'll take another stage error under 3%!  Martin's average speed was 42.80 kph (26.59 mph).

Our terrain model is pretty good.  After the Tour de France is completed, we'll do as we always do each year and look over the entire race and see if our model can be tweaked for various stage types.  We nailed yesterday's medium-mountain stage, and we weren't too far off today.

At 231 km (144 mi), tomorrow's Stage 7 is the longest stage in this year's Tour de France.  The flat stage commences in the northwest French commune of Fougères and takes cyclists due eat to Chartres.  Below is our model's prediction.
  • Stage 07:  5h 16' 33" (prediction)
With such a long stage, will the peloton keep the pace slow?  Or will a rider decide that he wants the podium at the end of the day and attack early?  I can't wait to see how it unfolds!

11 July 2018

Sagan Gets #2 and We're Nearly Perfect!

Peter Sagan out-sprinted Italian Sonny Colbrelli to earn his second stage win in the Tour de France.  Check out the screen capture I got (click on image for a larger view).
I was again watching the race from home and I was yelping on my couch when cyclists were a few km away from the finish.  We had another shot at perfection.  Check out our prediction for today.
  • Stage 05:  4h 48' 06" (actual), 4h 46' 53" (prediction), 01' 13" fast (-0.42% error)
For the second time in five stages, our error is 0.4%!  I'm thrilled with how our model has performed over the first quarter of the Tour de France.  Sagan averaged 42.59 kph (26.46 mph) during the nearly five hours he spent in the saddle.

Tomorrow's Stage 6 is another medium-mountain (or hilly) stage.  The 181-km (112-mi) stage begins in Brest, which is about as far west as one can get in France.  The commune of Mûr-de-Bretagne is where the stage ends.  Cyclists will have one category-4 climb and three category-3 climbs.  Our prediction is below.
  • Stage 06:  4h 06' 24" (prediction)
Will Sagan win another stage or settle for second place?  Or will someone else rise up tomorrow?  I can't wait to watch it!

10 July 2018

A Thrilling Sprint to End Stage 4!

Wow -- just wow!  I watched today's stage from home instead of my office.  I was on the edge of my seat when that final sprint started.  Those cyclists have me in awe.  As I've written before, I never tire of seeing elite athletes performing at the pinnacle of their métier Peter Sagan planned his push perfectly, but just couldn't catch Fernando Gaviria, who won his second stage in this year's Tour de France.  Another second place for Sagan!  André Greipel was pedaling his tail off and came in third.  Check out the screen capture below (click on image for a larger view).
Sagan is on the far left, Greipel is in red in the middle, and Gaviria is the one crossing the finish line first.  Want to see that from the side?  Check out the screen capture I got from a replay (click on image for a larger view).
Pretty close, huh?  Below is a comparison of Gaviria's winning time and our prediction.
  • Stage 04:  4h 25' 01" (actual), 4h 17' 52" (prediction), 07' 09" fast (-2.70% error)
When I kept hearing the announcers talk about a "massive head wind," I knew our prediction would likely be a bit fast.  But I'm thrilled to be under 3%!  Gaviria's average speed was 44.15 kph (27.43 mph).  Greg Van Avermaet maintains the yellow jersey and Tejay van Garderen is right there with him.

Tomorrow's Stage 5 gives us the first medium-mountain (or hilly) stage.  Beginning on the west coast of France in Lorient, the 204.5-km (127.1-mi) stage ends to the northwest in Quimper.  There are a couple of category-4 climbs and three category-3 climbs.  Our prediction is given below.
  • Stage 05:  4h 46' 53" (prediction)
I hope tomorrow's finish is as exciting as today's!



09 July 2018

BMC Takes Today's Team Time Trial!

BMC Racing Team was focused, determined, and flat-out great in today's team time trial.  Check out that grit (click on image for a larger view).
Every year, we need to tweak our power output and air drag.  Cyclists get more powerful, bikes get more aerodynamic, and team strategies get more efficient.  Science plays a major role in these advancements.  I got a screen capture of BMC crossing the finish line with their winning time (click on image for a larger view).
Below is a comparison between their winning time and our prediction.
  • Stage 03:  38' 46" (actual), 39' 59" (prediction), 01' 13" slow (3.14% error)
We've been slow on recent time trials.  I continue to marvel at how great these cyclists are and how much improvement there is from year to year.  BMC averaged 54.94 kph (34.14 mph), an average speed that boggles my mind.  And the reason it boggles my mind is because I can't imagine being good enough to cycle that fast for as long as they did, even if I could draft the entire time!

Belgian Greg Van Avermaet takes over the yellow jersey and Tejay van Garderen from my country sits in second place.  It's been an exciting start to this year's Tour de France with a new yellow jersey wearer after each of the first three stages.

Tomorrow's Stage 4 gets underway in La Baule on the west coast of France.  The 195-km (121-mi) flat stage finishes a little ways up the coast in Sarzeau.  Below is our prediction.
  • Stage 04:  4h 17' 52" (prediction)
Will the yellow jersey be waiting for someone new after tomorrow's stage?

08 July 2018

Sagan Wins and We're Nearly Perfect!

No second place for Slovakian Peter Sagan today as he won a thrilling sprint to take Stage 2.  Check out the finish in the screen capture I got (click on image for a larger view).
Sagan stretches forward, narrowly ahead of Sonny Colbrelli of Italy.  France's own Arnaud Démare is right behind in third place.  What a great finish!  Sagan now has the yellow jersey.  Racing was again fast, but when I saw the winning time come up, I nearly hopped out of my chair.  Check out how our prediction fared today.
  • Stage 02:  4h 06' 37" (actual), 4h 07' 38" (prediction), 01' 01" slow (0.41% error)
I'll definitely take that error!  Sagan averaged 44.40 kph (27.60 mph), a bit slower than yesterday's winner, but an elite average speed nonetheless.

Tomorrow's Stage 3 is a team time trial.  Still in western France, the 35.5-km (22.1-mi) race will be held in the commune of Cholet.  Can Team Sky get Chris Froome closer to the lead?  We shall see.  Our prediction is given below.
  • Stage 03:  39' 59" (prediction)
With drafting and good strategy on swapping out the lead cyclist, team racing can be very fast.  I look forward to seeing how it unfolds tomorrow!

07 July 2018

Gaviria Makes Colombia Proud!

Fernando Gaviria of Colombia out-sprinted Peter Sagan (another second-place stage finish for Sagan!) to take this year's first Tour de France stage.  Racing was fast and some late crashes tossed Chris Froome 51 seconds behind the leader.  Vincenzo Nibali, who came in 11th today with the winner's time group, has to be smiling now that he's got a lead on Froome.  Team Sky may have the edge in Monday's team time trial over Bahrain-Merida, but Nibali has a lead on Froome that he'll try not to lose before the first mountain stage.  A favorite of mine, Nairo Quintana, came in 112th today at 01' 15" back.

It was a great sprint at the end as speeds shown on the live feed I had reached 61 kph (38 mph).  I cropped this image from the replay of Gaviria crossing the finish line with Sagan right behind him and powerful Marcel Kittel coming in third (click on image for a larger view).
Now let's see how our first prediction turned out.
  • Stage 01:  4h 23' 32" (actual), 4h 36' 43" (prediction), 13' 11" slow (5.00% error)
That's a good, but not great, start.  Racing was definitely fast today.  Gaviria's average speed was 45.76 kph (28.44 mph).  Not too shabby for nearly four-and-a-half hours in the saddle!

Tomorrow's 182.5-km (113.4-mi) Stage 2 commences in the western French commune of Mouilleron-Saint-Germain.  The flat stage ends to the west in La Roche-sur-Yon.  Our prediction is given below.
  • Stage 02:  4h 07' 38" (prediction)
We were 5% slow today.  Will we do better tomorrow???

06 July 2018

Time for the 2018 Tour de France!

The World Cup has kept me so busy that the start of the Tour de France sneaked up on me.  My research student, Carl Pilat, and I have this year's model ready to go.  I'm always nervous with the first prediction!

Stage 1 begins in Noirmoutier-en-l'Île on the west coast of France and ends in Fontenay-le-Comte after 201 km (125 mi) of cycling.  The flat stage looks to be in a beautiful part of western France.  Without further ado, here is our prediction:
  • Stage 01:  4h 36' 43" (prediction)
Will we be fast?  Slow?  It's always fun watching the race and seeing how our model performs.  We can't know detailed weather information, teams' strategies, what crazy fans will do, and if crashes occur.  There are a lot of unknowns in predicting such a complicated phenomenon.  But that's part of the excitement!

24 June 2018

Toni Kroos' Amazing Bend Beats Sweden!

With just a few seconds left in extended time, Germany got the goal it needed to move past Sweden, 2-0, in yesterday's World Cup action.  The win put Germany in a great position to move on to the knockout stage.  Toni Kroos kicked the game-winner and it was a thing of beauty.  The image below shows Kroos just before he kicked the Telstar 18 (click on the image for a larger view).
The view from behind the goal shows what the Swedish goalkeeper had in mind (click on the image for a larger view).
He is protecting the part of the goal to his right, perhaps thinking the Swedish two-player wall and other defenders would be enough to keep the Kroos kick out of the part of the goal to his left.  One of the defenders in the Swedish wall actually flinched away from Kroos' kick!  Check that out below (click on the image for a larger view).
See the blur of the ball on the back of the Swedish defender at the bottom of the image?  Hey, I'd flinch, too, with a fast-moving ball coming right at me, but I bet they guy wishes his back had at least let the ball graze him.

Now it's time to look at the beautiful trajectory.  The Magnus force helped Germany win the match because Kroos put a lot of counterclockwise (as seen from above) spin on the ball by kicking the ball right of center with his right boot.   That led to a Magnus force pushing the ball to Kroos' left, which meant the goalkeeper might have thought the ball would be wide of the goal.  Check out the trajectory that I've labeled with circles below (click on the image for a larger view).
Look at the lovely bend!  That's a banana kick with whipped air!  As the ball spins counterclockwise, the boundary layer of air is being whipped off the back right part of the ball.  If the ball whips the air that way, Newton's third law says the air has to push the ball to the left.  And did it ever!  Check out the view of the bend from a lower angle (click on the image for a larger view).
Air resistance worked to slow down the ball and Earth's gravity pulled the ball downward, but that gorgeous bend is due to the Magnus effect.  Want to see how close the Swedish goalkeeper came to deflecting the ball?  Check it out (click on the image for a larger view).
See the ball just barely off his outstretched right hand?  Want another view?  Sorry, Sweden, but I've got to show it (click on the image for a larger view).
The image will surely give Swedish fans heartache, but sometimes the beautiful game comes down to mere inches.

Okay, let's get quantitative.  I know the aerodynamic properties of Telstar 18 (click here for my research paper).  Modifying the result in my paper with what we've learned about spinning balls, I modeled Kroos' kick.  Check out the trajectory plot below, which shows the trajectory in red (dashed red line is the shadow on the pitch) and what the trajectory would have looked like without the Magnus force in blue (dashed blue line is the shadow on the pitch).  The goal plane is also shown (click on the image for a larger view).

The perspective I have on my 3D plot isn't quite the same on the actual views I showed above, which is why the red trajectory doesn't look quite as curved as the trajectories I put on the actual images.  Television images are also a bit skewed.  But you can see how much the Magnus effect altered the trajectory from the no-spin case.

The ball was kicked at 67 mph at about 13.6 degrees above the horizontal.  The ball was travelling a bit more than 51 mph when it reached the goal plane, having been slowed by air resistance and converting some kinetic energy into gravitational potential energy.

I'll now show you the sizes of the drag force and the Magnus force on Kroos' kicked ball while in flight.  I scale the forces by the ball's weight.  The ball took almost a second to reach the goal plane (click on the image for a larger view).
Look how close to the ball's weight the two forces are at the moment the ball was kicked!  You can see why the ball slowed so much and curved so much on its way to the goal plane.  Had there been no air resistance, the ball would only have slowed 1 mph or so at the height it reached in the goal plane.

I loved watching the kick and I loved analyzing the kick.  Physics makes the beautiful game all the more beautiful!

22 June 2018

Match of a Lifetime for Nigeria's Ahmed Musa!

Ahmed Musa put on a show today as Nigeria defeated Iceland, 2-0, in World Cup Group D action.  The first of Musa's two goals was a thing of beauty.  After a scoreless first half, Iceland had a throw-in early in the second half.  Nigeria got control of the ball and once Victor Moses had the ball down the right side of the pitch, he was off to the races.  He kept looking toward his teammates to his left and he spotted Musa keeping pace.  Look where Moses launched his pass (click on the image for a larger view).
The ball is just leaving the right boot of Victor Moses in the above photo.  He kicked the Telstar 18 down and to the right, which gave the ball a lot of counterclockwise spin (as seen from above).  That meant the Magnus force was on the ball, causing it to curve from right to left (as seen by Moses) off its normal trajectory.  That was the perfect spin because the ball curved in toward Musa.

But the pass, like all passes, was not precisely perfect.  Musa put his athletic skill on full display as he caught the ball.  Check out Musa's outstretched right leg (click on the image for a larger view).
What you have to keep in mind is that Musa not only arrested the majority of the ball's velocity, his right boot was on the underside of the ball.  Whether by design or good fortune, that boot placement caused the ball to rotate counterclockwise -- as seen by Musa!  The ball's rotation axis had been turned 90 degrees.  Look at the closeup below (click on the image for a larger view).
It was great boot placement!  Musa's toes were up to help stop the ball's side-spin, but his ankle was on the bottom of the ball to take advantage of the ball's velocity and create the counterclockwise spin that Musa saw.  That meant that when the ball landed on the pitch, friction with the pitch would cause the ball to move toward the goal.  Muse wisely let the ball hit the pitch (click on the image for a larger view).
By letting the ball bounce off the pitch, Musa allowed the pitch to help the ball move toward the goal, and the ball was in a more stable position to kick with less speed than it would have had had Musa tried kicking the ball before it hit the pitch.  Look at the ball right before the kick (click on the image for a larger view).
Musa has the lean toward his left as his right leg comes through the ball.  He is about to kick the ball with a bit of backspin, so his boot will go through a line below the ball's center of mass.  How close did the ball come to getting blocked?  Check it out (click on the image for a larger view).
Look at how close the Icelandic goalkeeper was to the ball!  But the upward trajectory of a ball kicked at nearly 65 mph with backspin was too much for the goalkeeper.  At the instant shown below, Nigeria was on its way to victory (click on the image for a larger view).
Doesn't Telstar 18 look pretty in the goal plane?  I think so, but not nearly as pretty as Musa's goal!

14 June 2018

World Cup Starts Today!

To whet your appetite for the start of the 2018 World Cup, you can listen to Neil deGrasse Tyson and me yap about soccer science on last night's episode of StarTalk's Playing with Science.  Click on the link below to learn about soccer science in the World Cup.

My only complaint is that the graphics people at Playing with Science didn't use a Telstar 18 ball in the photo!  The last time the traditional 32-panel ball was used in the World Cup was in 2002 when the Fevernova ball was the official ball in South Korea and Japan.  Forget the photo and listen to the podcast!

21 May 2018

Newly Published Telstar 18 Research

My paper on this year's World Cup ball, the Telstar 18, finally went live this past Saturday.  The Journal of Sports Engineering and Technology has graciously allowed the paper to be open access at least until the start of the World Cup.  Click here to download the paper.  My colleagues and coauthors at the University of Tsukuba in Japan, Sungchan Hong and Takeshi Asai, created a short video (48 s) of the Telstar 18 in their wind tunnel.  I put it on my YouTube channel.
As a physicist, I love seeing all the clever ways we humans have devised to study our world.  Wind tunnels are marvelous machines that allow us to determine aerodynamic properties of numerous items, including soccer balls.  Check out our paper and see how I take my colleagues' wind-tunnel data and use it to predict trajectories of Telstar 18 in flight.  We compared Telstar 18 to Brazuca, which was used in the 2014 World Cup in Brazil.  Check out how Telstar 18 will fly in Russia.  Just 24 more days until the start of the World Cup!

19 April 2018

World Cup Soccer Ball Physics

Last night's episode of StarTalk's Playing with Science got us primed for the World Cup, which begins in Russia on 14 June.  I was on during the last half hour or so of the show and talked about my latest published research.  My colleagues at the University of Tskuba in Japan, Takeshi Asai and Sungchan Hong, have worked with me on several research projects.  We showed in 2014 why Brazuca was superior to Jabulani, balls used in 2014 and 2010 World Cups, respectively, and we have just published research on the Telstar 18, which is this year's World Cup ball.  My colleagues got wind-tunnel data on the ball and I did all the data analysis and trajectory modeling.  It's a great partnership!  I discussed the aerodynamics of the new ball and compared it to Brazuca on last night's show.  Click on the link below to hear all about it.

I simply LOVE talking about sports physics, especially the flight of soccer balls.  It's too bad that Russia is a bit out of my travel range this summer.  I would love to see the new ball in action.  I will do like most of the world and watch on television.  The photo below (click on image for a larger view) shows me holding Brazuca (right hand) and Telstar 18 (left hand).  At $160 apiece, I'm glad that I don't have to buy the balls!
I thank John McCormick here at Lynchburg College for taking that photo.

11 April 2018

Cheating and Physics in Cricket

The international sports world was recently rocked when the Australian cricket team was caught cheating during a test match against South Africa.  A bowler was filmed roughening up a ball with what appeared to be sandpaper.  It is nearly impossible to compete on the elite stages of sport and not have every move filmed with high-definition video.  I discussed the physics of cricket, specifically the aerodynamics of the ball in flight and how cheating leads to "reverse swing," on tonight's episode of StarTalk's Playing with Science.  Click on the link below for the episode.
I love talking about the physics of sports, but I hate it that a cheating scandal prompted my participation.  Honesty is of paramount importance to me and I hate to see cheating in sport.  If you can't quite reach the mountaintop, train harder!  If you still can't reach the mountaintop and you've done your best, accept the fact that not everyone can be #1 at the same time.  There are worse things in the world than being the 10th best cricket bowler or 5th best home run hitter or 15th best cyclist.

I do hope you enjoy the episode.  I had a blast talking cricket physics.  I even had my own cricket ball to use for demonstrations!

08 March 2018

Great Time at AFIT!

My trip to the Air Force Institute of Technology earlier this week was very quick, but a lot of fun.  My host, Adedeji Badiru, is someone I first interacted with about eight years ago, but only met in person for the first time during my visit.  I had a great audience for my talk, many of whom serve in our armed forced (mainly Air Force).  My talk began with something new for me and something I felt really good about doing.  I thanked those in the audience for their service in our country's armed forces.

My talked focused on research my students, colleagues, and I have done with World Cup soccer balls and with modeling the Tour de France.  In the photo below, I'm talking about the Brazuca ball used in the 2014 World Cup in Brazil (click on image for a larger view).
During the part of my talk when I discussed the Tour de France, I had to show a classic from introductory physics:  the inclined plane (click on image for a larger view).
It was kind of the people hosting me to snap a few photos while I was giving my talk.  I got some great questions afterwards and now have a couple things to think about regarding future work.  There is nothing like sharing science and getting feedback from curious, smart people.

I had about two hours after my talk before I needed to get to the airport.  On the advice of my host, I stopped at the National Museum of the United States Air Force.  Wow!  That place is amazing and I thoroughly recommend stopping there if you are close to Wright-Patterson Air Force Base near Dayton, Ohio.  There is no charge to get in and so many wonderful exhibits and planes await you.  I was thrilled to walk through President John Kennedy's Air Force One, the VC-137C SAM 26000 (click on image for a larger view).
Being in the plane where Lyndon Johnson was sworn in after John Kennedy was assassinated was a little chilling (click here for a very famous photo).

What really got me giddy was seeing equipment used by the Wright Brothers in their flight experiments.  As someone who plays with wind-tunnel data for soccer balls, I truly loved seeing the wind tunnel shown below (click on image for a larger view).
Is that not cool, or what?!?  I'll definitely have to make a return trip to Dayton and spend more time in that wonderful museum.

27 February 2018

Invited Talk at AFIT Next Week

I was extremely flattered to be invited to give a talk at the Air Force Institute of Technology as part of their Dean's Distinguished Guest Speaker series.  I'll be at the Wright-Patterson Air Force Base near Dayton, Ohio.  Below is a flyer for my talk (click on image for a larger view).
If you happen to be in the Dayton area, stop by for some fun sports physics!

22 February 2018

The Thrills and Speed of Alpine Skiing

Tonight's episode of StarTalk's Playing with Science concerned alpine skiing.  Erin Mielzynski and Andrew Weibrecht joined us on the show.  It was a blast talking to them!  You won't believe how fast one can fly down a hill on skis.  Click on the link below to listen to the show.
This is the third of three Winter Olympics shows I recorded.  Meeting great athletes and learning a little bit about how they train and perform has been thrilling for me.  My jaw drops when I see them in action.  Teasing out all the great physics only makes what they do all the more fascinating!

16 February 2018

Ronaldo's PK: Black Magic or Simple Physics?

Did you see the crazy penalty kick Real Madrid's Cristiano Ronaldo let loose against Paris Saint-German this past Valentine's Day?  In the 45th minute, Ronaldo blasted the ball into the left side of the net.  What made people's jaws drop was what happened to the ball just prior to Ronaldo's famous right boot making contact with the ball.  The ball popped off the turf!  You can see the video here where "black magic" is referred to.

I did a frame-by-frame analysis for i News in the UK.  There was, of course, no black magic involved!  Check out the images below (click on image for a larger view).
As Ronaldo planted his left boot, a pressure wave was initiated in the turf.  A crinkle was all it took to get the ball to hop off the turf about a centimeter.  Click here for more details in the story by Will Magee.  Getting ball off the turf prior to kicking saved a little energy loss from friction between the ball and turf.  Hard to stop that shot!

15 February 2018

Curling is AWESOME!

StarTalk's Playing with Science aired an episode on curling yesterday evening.  I had a LOT of fun doing that episode!  Curling is one, cool spot.  There is plenty of fascinating physics and an unanswered question or two.  Check out the show via the link below.
My plan was to post the above show's link last night, but the shooting in Florida took my thoughts elsewhere.

How many slaughtered will it take?

My cousin notified me of yesterday's atrocity in southern Florida.  Broward County?  That's where my sister's family lives and where her kids go to school.  I called my sister.  "Is that [my nephew]'s school?"  "No.  His school is in the neighboring district."  Marjory Stoneman Douglas High School in Parkland is eight miles from my sister's house.  She described to me scenes of roads packed with cars as parents raced to their kids.  Friends of my sister had a son in that school yesterday.

What I described above is as close as I've ever been to a school shooting (I did know a student at Virginia Tech in 2007).  I know what's it like to lose a child.  I know what it's like for a moral monster to steal half my children's childhoods from me.  I know what's it like to be told a friend was murdered with a gun.  I've known parents who watched a state trooper pull his car in their driveway and inform them that their child was killed in a car wreck.  My guess is that anyone reading this will share some or all of what I've experienced.  I suspect there is a reader or two who has been directly affected by a school shooting.  I don't know what it's like to send one of my daughters to school and never see her alive again.  I hope I never experience such a horror.  Any tragedy in my life pales in comparison to a parent sending a child off to school, only to have that child be murdered.

How many dead children are enough?  How many people, simply going about their lives, working, playing, etc have to be slaughtered before the needle of sense moves in my country?  When do we in the US have our Dunblane?  When do we have our Port ArthurSandy Hook saw 27 murdered, but that didn't change anything.  Last October, 58 people were shot dead in Las Vegas, but that didn't change anything.  I couldn't possibly list all the mass shootings in the US because I have to feed my girls dinner in a couple hours.  I read yesterday (click here) that we've now had four shootings at middle and high schools in 2018.  Yesterday was just the 45th day of the year.  Children are taken through "shooter in the building" drills in schools in present day America.  My girls never did that during their school year in England.

We are learning about all kinds of mental issues associated with the loathsome individual who destroyed countless lives yesterday.  What astounds me is that many of the same people who so ferociously defend our "right" to own and use an AR-15 or a Bushmaster or some other military weapon simultaneously rail against universal health care and more money for mental illness treatment.  There are plenty of people with mental issues in countries that have serious gun restrictions.  This problems isn't confined to mental issues.  The ease of obtaining a weapon that can end many lives in a short time is obscene.

Like many other politicians, President Trump offered "prayers and condolences" yesterday.  No matter how good the intentions or how warmed people may be to receive "prayers and condolences," I have to ask, when is that bullshit going to end?  When are people going to embrace reality and actually DO something in the here and now?  Will it take a politician's kid being murdered to get something done?  What if a lobbyist's child gets shot at school?  Or a celebrity's kid?  Does the death count have to reach triple figures in a massacre to make us think that, perhaps, we don't need assault rifles?  Are we going to go nuts in the other direction and have guards armed to the teeth walking down every corridor in every school?  I need not insult my readers by detailing the absurdity of that scenario.

If by chance anyone is reading this that has been affected by a school shooting, please know that I'm filled with sadness and anger over what happened yesterday.  Kids in Parkland are not alive today because of a "blessing" or "luck."  They are alive because they were not in the wrong place at the wrong time.  The power to take a life, many lives in fact, is too easy to acquire in my country.  Four shootings in middle and high schools in just 45 days so far this year.  What's in store for the next week-and-a-half?

07 February 2018

Winter Olympics! Let's Talk Figure Skating!

Tonight's episode of StarTalk's Playing with Science will get you ready for the Winter Olympics, which begins this Friday in PyeongChang, South Korea.  We talked figure skating, which is so many people's favorite event come Winter Olympics time.  A very special guest is on the show, Olympic Medalist Sasha Cohen.  I have such wonderful memories watching her compete in the figure skating competition at the 2006 Winter Olympics in Turin, Italy.  My older daughter, Emily, and I rooted Sasha on like crazy.  Emily wasn't quite two-and-a-half at the time, but she got a great introduction to Olympic skating.  My younger daughter, Abby, was born less than a month later.  I recall patting my wife's belly and telling Abby to root for Sasha while she skated.  Abby doesn't remember that!  Sasha took home the silver.

The link for tonight's show is given below.  Also on the show is Jackie Wong, who I thoroughly enjoyed talking to.  He hosts the podcast Ice Talk.   Check it out!
The video producer at StarTalk was kind enough to send me a screen capture when I was posing a question to Sasha Cohen (click on the image below for a larger view). 
I actually had to leave the show earlier than I wanted.  I had to drive across town and give a keynote address at Randolph College.  No need to have a tie on otherwise!

03 February 2018

Physics of the Quad Cork 1800

I worked on a piece for WIRED Magazine that appears in its February issue.  Billy Morgan successfully executed the famed snowboarding trick known as the quad cork 1800.  I analyzed the trick from start to finish and WIRED has a phenomenal two-page photographic spread that shows the entire trick from stroboscopic images.  I calculated several numbers, from launch speed to landing force.  Check out the nice spread on pages 20-21 (volume 26, issue 2).  I worked with Sophia Chen on the piece and she did a great job putting it all together!  Click here for a sneak peak.

01 February 2018

Great fun giving my talk!

I thoroughly enjoyed giving the keynote address at Randolph College last Saturday for the United States Association for Young Physicists Tournament (USAYPT).  My audience got to hear about my Tour de France research and my research on World Cup soccer balls.  It was my first chance to speak about the Telstar 18, which will be used in Russian during this summer's World Cup.  My friend and colleague Peter Sheldon took the photo below as I was on stage giving my talk (click on image for a larger view).
During talks and media experiences, I like to sell the virtues of my college, Lynchburg College.  I'm always looking for new students to join us at Lynchburg College, major in physics, and contribute to my research.  Students have always played a central role in my sports research.  I was treated very well at Randolph College and I'm happy give that school a shout-out here.  Check out what Peter has going on in the Department of Physics there!

24 January 2018

Martial Arts Repeat

Tonight's Playing with Science episode is a repeat, but it happens to be the fan favorite episode for 2017 (click here for the poll results).  If you missed the martial arts episode, check it out!
I'm thrilled fans of the show voted this episode their favorite Playing with Science episode.  I'm in the process of completing my Krav Maga book.  I hope it'll be available early in 2019.

23 January 2018

Keynote Talk this Saturday

I was extremely flattered to be asked to give the keynote address for the United States Association for Young Physicists Tournament (USAYPT) at Randolph College here in Lynchburg.  My talk will be this coming Saturday, 27 January 2018, at 4:15 pm in Smith Hall Theatre.  A poster appears below (click on image for a larger view).
This will be my first talk of the year, and it will be the first talk in which I discuss the Telstar 18 soccer ball, which will be used in Russia for this year's World Cup.  I look forward to meeting the talented high school students at the tournament!

18 January 2018

Playing with Science Mix

StarTalk's Playing with Science put together a nice mix from the first two seasons.  I get to chime in on the show.  Click the link below for last night's episode.
It was a lot of fun working with Playing with Science in 2017!  Who knows what's in store for this year with the Winter Olympics and World Cup ...?

31 December 2017

Physics and Psychology Aid Callahan's Punt Return TD!

The Chicago Bears finished a rather dreadful season with a loss to the Minnesota Vikings today, 23-10.  The Bears did have a fun play that I got to analyze for TuneIn's Ho Huddle.  With just over six minutes left in the first half, the Vikings faced a 4th and 9 at their own 16-yard line.  Vikings' punter Ryan Quigley (#4) punted the ball from Minnesota's 7-yard line (click on image below for a larger view).
You can see in the above screen capture that Quigley was right on the 7-yard line when the ball left his right shoe.  The ball was punted at almost 60 mph and over 60 degrees to the horizontal.  For an incredibly short amount of time, the force between shoe and ball on a good punt can be over 1000 pounds.  The punted ball traveled 53 yards and had a hang time of 4.24 seconds.

The problem for the Vikings was that the Bears' Tarik Cohen (#29) played the perfect decoy.  He was on the right side of the field and acted as if he was going to catch Quigley's punt.  But Bryce Callahan (#37) was on the left side of the field and caught the punt while sliding on his own 40-yard line (click on image below for a larger view).
Look at Cohen with his arms out like he's about to catch the punt!  The Vikings' Jayron Kearse (#27) is running full speed at Cohen while Callahan has just caught the punt.  The screen capture below shows when Callahan got up after his slide (click on image for a larger view).
You can see the purple blurs heading toward Cohen!  I couldn't tell from the video I watched, but Quigley should have been yelling at his teammates, telling them where his punt was headed.  Even though the Vikings were at home, the noise level could have been in the 70 dB - 100 dB range, which corresponds to the sound a vacuum cleaner makes all the way up to what a busy subway sounds like.  Quigley's teammates down the field probably wouldn't have heard him if he was yelling.

Callahan could get up after his slide and run because the NFL doesn't use college football rules.  The screen capture below shows that Callahan had many blockers in front of him (click on image for a larger view).
The Vikings are headed to the right while Callahan is preparing to run down the left side of the field.  Cohen did such a good job selling the fake that Kearse nearly ran into Cohen and had to veer off to Cohen's left upon realizing that Cohen didn't have the ball.  Check out the screen capture below, which shows five Vikings near Cohen, all realizing too late that they ran after the wrong player (click on image for a larger view).
Meanwhile, Callahan was hitting a top speed of 19 mph in Vikings' territory (click on image below for a larger view).
Callahan crossed the goal line at about 16 mph, having slowed a little to celebrate (click on image below for a larger view).
A lot of great physics for sure, but psychology had the Vikings off course and chasing the wrong Bear!  The Bears finished 5-11 this year, but left me with a fun play to analyze before bringing their season to a close.

Chuck Nice of Playing with Science joined me on today's segment.  As he always does, Chuck set up the play really well before tossing it over to me for the nerdy stuff.  Click here for our segment.  The NFL regular season finished up today, but like the 13-3 Vikings, we football fans are anxious for the playoffs to begin!