
Real Life Physics
6/16/2021 | 26m 46sVideo has Closed Captions
The physics of hammers, traffic jams, jumping springtails & the overuse of a NC state park
Learn how physics helps an NC company manufacture 600 different hammers, see the science behind traffic jams and how AI could help stop them, watch springtail insects jump and flip, and learn how a state park is in danger of being overused.
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SCI NC is a local public television program presented by PBS NC
PBS North Carolina and Sci NC appreciate the support of The NC Department of Natural and Cultural Resources.

Real Life Physics
6/16/2021 | 26m 46sVideo has Closed Captions
Learn how physics helps an NC company manufacture 600 different hammers, see the science behind traffic jams and how AI could help stop them, watch springtail insects jump and flip, and learn how a state park is in danger of being overused.
Problems with Closed Captions? Closed Captioning Feedback
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Learn Moreabout PBS online sponsorship[light piano music] [funky electronic music] - Hi there.
I'm Frank Graff.
Can artificial intelligence stop traffic jams?
Check out what a globular spring tail can do, and well, you know what this is, a North Carolina company is taking the hammer to a whole new level it's hammer time, coming up on Sci NC.
- [Female Narrator 1] This program was made possible by contributions to your PBS station by viewers like you.
[light upbeat music] - [Female Narrator 2] Additional funding for the Sci NC series is provided by G S K. [funky electronic music] ♪ - Hi again, and welcome to Sci NC.
The hammer is one of the earliest tools ever invented.
In fact, archeologists call those first hammers hammer stones.
They were literally large flat stones used to hammer.
While in today's high-tech world, thanks to material science, a North Carolina company has developed a hammer for every need.
[metal bang] - We make hammers.
[hammer clanking on metal] We make 600 different hammers.
[hammer clanking on metal] - [Frank] And those 600 types of hammers are needed [industrial saw buzzing] because of material science and physics.
[hammer hitting loudly] - We're in the non-ferrous metal industry.
So, non-ferrous is non-magnetic, and because it's non-ferrous, it's soft.
Our softest metal that we deal with is lead, and then we go up to aluminum.
Feel the weight of that.
- Wow, yeah, that's... Yeah.
- The same pattern made this.
Feel the weight of that, quite a bit of difference.
- Yeah, big difference.
- So let's say you as a customer who needs a hammer, and you need it to not damage whatever metal you're working on.
You're working on an expensive part, or how about this?
Here is a thousand dollar Halliburton wheel off your Cobra that you have at home.
This is very expensive.
This piece alone is $400, but you need to remove or you need to put it on.
[hammer clanging against wheel] By doing this, you're going to tighten that on your vehicle but you're not going to damage this.
You're going to damage the hammer.
The hammer is much less expensive to replace than that, but you need the impact.
You need that dead blow in order to get that on or get it off, especially when it's been superheated after a day of racing.
This is just a small example of what we do, but the principle's the same.
Soft metal head doesn't damage the metal that you're working on.
- So are you looking at, so I'm going to call and say this is what I need the hammer for, - Right.
- So you're going to check what that's made of and then you're going to match that to the hammer to do the job?
- Yes.
We always want to make sure that our metal is softer than the metal that they're hitting on.
So again, all 600 hammers that we manufacture have a very specific application.
[hammer tapping anvil] - [Frank] American Hammer makes what could be one of the simplest tools ever invented, from the earliest of civilizations, up to the present day, the hammer solves a problem.
[high pitched whirring] And the Wilmington, North Carolina company ships its hammers all over the world.
- [Ted] A heavy week, we're producing about 3000 hammers.
- [Frank] Pretty much every industry?
- All metalworking, plastic injection molding, automotive, aerospace, nuclear power.
This is for the cryogenics industry.
This is the hammer that will be on the back end of tanker trucks that are delivering compressed gas.
And this hammer can withstand temperatures of 400 degrees below zero.
They could not have a composite handle.
They could not have an aluminum handle and a steel shaft because of sparks.
They are critical non-sparking environment, no steel, no wood, because the wood would shatter.
No fiberglass, they would shatter.
And the same with the composite they needed a solid material, in this case, bronze, they needed it certain length, certain face diameter.
This is a really over-gripped.
And why?
Because they're using a very thick glove.
They're doing one thing, and one thing only with this hammer, they're taking off a CGA nut.
It's a big wing nut, and they're hitting it, It spins off, They're putting their hose up to it, They're clamping it back down, and that's it.
[light hammer strike] - [Frank] Hammers are all made in essentially the same way.
No matter the type of metal required to solve a problem.
- [Frank] What do you call this, is that the mold?
- That's the mold.
Yeah.
- [Frank] That's the mold.
- That's just the mold.
- [Frank] And this is gonna be the - Handle.
Yeah, we just put it in here, And I've got a block of wood I could have over there, and I put it on here and I run, put a level on it to make sure it's level, And then I simply pour.
Now, the reason I'm doing this, is the ladle has to be about the same temperature as the lead.
That's the 700 degrees.
But once it cools down to about 575, this starts getting solid.
As I pour it, I can tell if it's not working right.
- [Frank] Molten metal poured into a mold.
Each metal requires a specific temperature for melting.
Each hammer is then shaped as the metal cools.
- [Allen] This is it's open.
I got to start fashioning the top as soon as possible or I got to take it out, re melt it and do it all over again.
- [Frank] If there's a problem, the defective hammer is simply melted down and recast.
[Metal thumping on table] Break off the excess metal, smooth, polish [hammer banging metal] And a hammer is created.
- This is an 18 pound sledgehammer, there you go, 18 pounds.
[heavy metal guitar riff] - [Ted] I am a problem solver.
I just heard the phone ring just 10 minutes ago.
And usually that's what happens: I'll get a call.
We have this issue.
We have this problem.
If we don't have a hammer of the 600 that we make, I'll come up with another hammer just to solve the problem that that customer, or that potential customer, had.
[heavy metal guitar riff continues] - Hammers are a good example of how science is part of everyday life, Both the good and the bad.
Hammers are good.
Traffic, bad.
The science of the horn honking headaches of getting from here to there is explained in our story from "Overview."
PBS North Carolina produces the series, "Overview," for PBS Digital Studios.
- [Male Narrator] There are a bunch of causes of traffic jams that make sense, like weather, special events, road work.
Then there's the kind of traffic that occurs out of nowhere.
It's surprising.
Some might even call it spooky.
Well, they probably wouldn't call it that, but scientists actually do call that type of traffic a phantom traffic jam.
And while the experience is more annoying than spooky, the larger impacts of traffic are actually terrifying.
- [Dr. Bayen] Traffic induces a lot of problems- emissions, pollution.
There's a clear correlation between the number of fatalities and accidents, and congestion.
Traffic has become one of the major problems plaguing cities all around the world these days.
- [Male Narrator] So what if I told you our cars themselves might help us solve traffic?
Meet Dr. Alex Bayen, He's kind of a traffic whisperer.
Dr. Bayen is the director of the Institute of Transportation Studies at UC Berkeley, and the director of aerospace programs.
So, it doesn't take a rocket scientist to solve our traffic woes, but like, it helps?
- [Dr. Bayen] Traffic congestion in cities started to become a real problem after World War II, with the acceleration of the automobile.
- [Male Narrator] In the nearly 100 years since the transportation engineering community started trying to understand it, no one has yet been able to solve traffic with science.
Generally, we understand that traffic occurs when the cars on the road require more space than what the roadway can accommodate.
There's a critical density after which small behaviors from drivers can start to seriously jam up the road.
And when that critical density is surpassed, the flow of the roadway becomes unstable, resulting in waves of stop and go traffic.
- [Dr. Bayen] In the early ages of traffic engineering and traffic theory, scientists modeled traffic flow of vehicles as fluid in pipes.
If you observe the propagation of waves in a river, what you will see is shock waves propagating, just like on the freeways.
- [Male Narrator] Traffic scientists have a grasp of the catalyzing events that set off a Phantom traffic jam, and theoretically, what it would take to prevent them.
In order for traffic to flow smoothly, drivers have to maintain a consistent speed and keep an even distance from the cars around them.
Seems simple, right?
Wrong.
Turns out, we are awful at this.
- [Dr. Bayen] Humans are very eager to catch up with the car in front of them, but this is actually the cause of a lot of inefficiency in traffic.
- [Male Narrator] So traffic can actually be caused by our own selfishness.
The desire to get your car to its destination at the expense of all others.
Then, when we realize the roadway is full, and we have to brake suddenly to stop from hitting the car in front of us, we can send ripples of traffic for miles behind us.
- [Dr. Bayen] There was an experiment in 2008, by a group of Japanese researchers.
People were asked to drive in a circle at a given pace and maintain their distances with the vehicle in front of them.
It's a simple task, you would think.
- [Male Narrator] But phantom jams started to occur in under a minute.
Now, check out this experiment that researchers at Vanderbilt University and the University of Arizona did about 10 years later.
This time, they inserted just one automated vehicle in the group.
See that arrow turn red?
That is where the driver let the car drive itself.
You can see as soon as a human driver is taken out of the equation, fuel consumption is reduced by 42%, and that stop and go traffic is smoothed out.
Dr. Bayen believes that if as few as one out of 20 vehicles on a roadway were connected and automated, they could guide human-operated vehicles to create a steady flow of traffic instead of phantom jams.
Bayen thinks the automated vehicles can induce the whole population to behave collectively better.
Maybe this all sounds a bit alarming - machines acting to improve human behavior?
Dr. Bayen doesn't think it's that far of a leap from a feature that many drivers use today.
- [Dr. Bayen] If you have a car that has cruise control, at some point, when you feel comfortable, you might engage it because you don't want to be adjusting the speed back and forth.
The notion of autonomy on demand is similar.
Once these features start to also encompass lane changes or longitudinal control, or keeping up with the person in front, the experience would be nearly identical.
At some point, you would engage these new features, and then the car will do it for you, just like it's doing it for you now when you do cruise control, and you probably don't even think about it.
- [Male Narrator] Bayen's team has created a variety of digital models to simulate traffic scenarios that capitalize on various levels of autonomous participation.
The tool is aptly named "Flow," and it's the first application of deep reinforcement learning with traffic micro simulation tools.
The team has tested their tool on loops, figure eights, and ramps.
In a figure eight simulation, just one automated car in 14, doubled the speed of all the cars in the course, and they were able to get twice as many cars through a ramp with just one in 10 automated vehicles.
In real-world scenario, the connected cars would be able to anticipate slowdowns ahead by communicating with cars in front of them, and maybe the roadway itself.
It would then match their speed to the average speed of the entire roadway, which would prevent sudden slowdowns from forming in the first place.
In instances where a phantom jam has already occurred, the connected vehicle could dampen the shockwave by maintaining a steady flow and even distance from the car in front of them.
So what is this technology that allows a car to react in real time to traffic scenarios?
Bayen and his team are diving into the world of deep reinforcement learning.
- [Dr. Bayen] Reinforcement learning algorithms have the ability to learn by optimizing a reward function.
It's an iterative process.
Every attempt the algorithm does to do things better, it gets a reward.
And if the reward keeps improving, then the algorithms will keep searching in the proper directions.
Now, how can that be used for traffic?
If you want to try to smooth traffic, the reward will try to penalize the waves.
- [Male Narrator] And there are decisions that the AI is making in these simulations that are a surprise to Bayen himself.
- We already see a lot of cases where artificial intelligence has exceeded the ability of the humans, but we can't really explain why.
- [Male Narrator] Learning from algorithmic simulations is one thing, but these systems are also learning from real world traffic.
- [Dr. Bayen] One of the threads that is particularly exciting these days in reinforcement learning is pixel learning.
Pixel learning is the ability to learn from pictures.
In the past, a lot of algorithms have learned from modeling the car, and based on that, learning what to do with it.
But recently, with pixel learning algorithms, I've learned to learn from the rendering of the car.
There's a lot of different images from which algorithms can learn, and this has deep implications because that means that in order to learn how to improve traffic, maybe you don't need to measure as much as before.
Maybe all you need to do is to have enough video footage so that you can learn from it.
- [Male Narrator] And cameras are coming to our roadways and our cars in increasing numbers.
As of 2018, every car that is sold in the U.S. is required to have at least one camera- the backup camera.
And transportation departments across the country are busy installing cameras on roadways.
So how close are we to seeing the positive impacts of this research on our roadways today?
- [Dr. Bayen] What's missing in order to enable this multiple vehicle coordination in the spirit of achieving the greater good for traffic is the ability to create a communication paradigm by which the vehicles start to collaborate.
- [Male Narrator] Currently, there is no one group that is bringing the private sector, scientists, and the public sector to the table to talk about the future of our roadways and driverless cars.
So Bayen and his team are working to build partnerships with everyone involved to do just that.
They've been supported by the Department of Energy, The National Science Foundation, and some private car manufacturers.
- [Dr. Bayen] Travel is such an important part of human life.
I really believe we can make travel better.
Where better is not just a better experience, but really something that is better for our planet.
- [Male Narrator] To gain back our wasted time in traffic, increase safety for everyone on the road, and mitigate some of the environmental impacts of our transportation systems, we're going to have to learn to act collaboratively.
That spirit of cooperation and altruism, along with our increasingly intelligent cars, might just help us finally solve traffic.
[funky electronic music] - Lately, more people are getting out of traffic, out of work, out of our homes, and getting outside, and that is a good thing.
But, as students from the UNC Hussmann School of Journalism and Media show us, it is a challenge for state parks.
- [Female Narrator] In January, 2019, more than 19,000 visitors flocked to Crowders Mountain State Park in a single weekend.
Ranger Kelly Cook has worked at the park for more than 20 years.
[ATV door closing] - I'm worried that some of our state parks, in our state park system, are going to basically be loved to death.
They're going to be loved to the point where people wonder why anyone ever came to them in the first place.
- [Female Narrator] Crowders Mountain State Park opened in 1974.
At that time, nobody knew just how fitting the name would become.
Since 2012, park attendance has almost tripled, reaching close to a million visitors a year.
One big reason, the park's location - just 40 minutes West of Charlotte.
Cook says the huge influx of hikers is eroding the terrain, like this abandoned trail.
- [Ranger Cook] This will never recover within our lifetimes.
Even if we brush pile this, nobody ever walks on it again, you will be able to come back in 50 years and still see where this is through here.
- [Female Narrator] Heavy foot traffic is also threatening plant species that serve as habitat and food sources for animals.
Since many of the parks trails run along ridge lines, where soil is already thin and rocky, foot traffic compacts the soil.
Plants no longer can take root.
- There are areas on some of the summits where, you know, there used to be some fairly nice blueberry patches and stuff, and those blueberry patches don't exist anymore because they've been just literally stomped out of existence.
[gravel crunching] - [Female Narrator] Overcrowding also threatens this Ground Juniper.
State parks Biologist, Sharon Bischof, says this Ground Juniper is well adopted to harsh soil conditions found along ridge lines, just where hikers are walking.
- It's right on the edge of the trail, and it's very easy to miss and easy to walk right through and never see it, especially if there's lots of people here, you wouldn't even notice.
- The bear Oak is another rare species found a Crowders Mountain.
This short, scrubby tree thrives after fire opens the forest canopy.
In some state parks, staff set controlled burns to open the canopy.
Trouble is, at Crowders Mountain, park officials are so busy handling crowds, they have little time or resources to do other work.
- We want folks to connect with our parks and have that positive experience and affinity for our parks.
But we also, part of our mission is to protect the resource and conserve these populations so that they can persist.
- [Female Narrator] But it doesn't take a biologist to see the impacts of overcrowding.
- Trails, are like, packed, there's always going to be like someone on the path with you.
- There are some little side trails that are starting to pop up because people get lazy and don't want to, you know, take the switchbacks.
- The trail is very eroded.
There's a lot of rocks on the trail.
- [Female Narrator] Park staff used to teach multiple nature programs every weekend, but now spend more time handling crowds.
[car honk] - Our over visitation keeps us from doing educational programs so we can't educate the public and make them aware of what they're having an impact on.
And, you know, therefore it just gets worse, you know, and I don't know how to solve that problem.
- [Female Narrator] Cook says many use the park as a gym to exercise, but he laments some go home without appreciating nature around them.
- Going back to when I started with the division, the primary user, primary hiker that we had come to the park was someone that was coming to enjoy nature, to you know, basically just be out in the natural environment.
They were looking for solitude.
You know, they were just looking to get away from things.
At any given point on any weekend when you were on one of the trails, unless it was pouring rain or just miserable weather, you are not going to be alone.
You will either see people in front of you, have people behind you, most often the case is it's both directions.
- [Female Narrator] Safety is a major concern.
With no protective rails at the pinnacle, visitors can crowd as close to the sheer rock cliffs as they dare.
Children, dogs and selfie takers don't always realize the dangers.
Since 2014, 3 people have died in falls at Crowders mountain.
- We try to tell people when they go to the top, don't get any closer to the edge than the height, than your own height.
That way, if you happen to fall forward, somebody stumbles into you.
You're going to fall down on the ground and not fall off the overlook area.
- [Female Narrator] Despite the crowds, the North Carolina State Park System doesn't plan to charge visitor fees at Crowders Mountain.
In fall 2019 two new parking lots were under construction at a cost of an estimated $750,000.
These slots will accommodate 200 more vehicles and allow more visitors to enjoy the park.
But in the meantime, parks staff have no easy answers for how to manage the crowds and still preserve the natural habitat.
[techno music] - Jumping and spinning faster and higher than anyone sounds like an honor for an Olympic athlete, but Adrian Smith at the North Carolina Museum of Natural Sciences tells us in the insect world, it's the globular springtail that would take the gold.
- [Male Narrator] This little creature is a globular springtail, and you're about to watch it jump and spin faster than any other animal on Earth.
Ready?
When it comes to jumping bugs, there's nothing quite like a springtail.
It's not technically an insect, it belongs to a group of animals called collembola, and most importantly, they are everywhere!
I wasn't even planning to film or study them, but then they showed up in huge numbers here on the lid of my trashcan.
After a rain, they'd climb out of the malts and hang out here on the lid.
They're called springtails because they use a tail-like appendage to spring themselves away from danger.
So I brought them back to the lab and started filming them, and now I'm proud to say that part of my research is on trashcan springtails.
There's been very little research done describing the jumps of springtails, which honestly is astounding.
These are some of the most high performance animals out there.
So, for a start, I've been filming the jumps in slow motion and tracking them frame by frame.
I've filmed about 50 individuals, and the data we've gotten back is incredible.
Here's the coolest part, when that spring tail took off it was spinning at a rate of 374 flips per second.
That's equivalent to 22,440 rotations per minute.
To put that in perspective, the main rotor of a helicopter spins between 250 and 600 RPMs, while the max RPM of most race car engines range from 7,000 to 15,000.
So, these tiny little springtails, as far as I can tell, are likely the fastest spinning animals on Earth.
The fact that the fastest back flipping animal is something I can go outside and find crawling around in my yard is amazing to me.
Their jumps and spins are all powered by a spring-loaded fork tail tucked underneath their body, called the fercula.
When it's released, the underbelly of the spring tail folds open and throws the tail down and around the body.
The details of which parts of the body make up the energy-storing spring and how the tail is released at the start of the jump are mostly unstudied and unknown.
But, so far, we've recorded an average upwards acceleration of around 700 meters per second, squared, which puts springtail jump performance beyond other fast jumping insects, like leaf hoppers.
Springtail jumps are incredible, when you consider what they're doing relative to how tiny they are.
For scale, here's one next to the tip of a toothpick.
It's only about one and a half millimeters long, and one millimeter tall.
A more or less vertical jump looks like this.
At the apex of this jump, The spring tail is 48 millimeters off the ground, And its rate of spin has fallen from 255 to 150 flips per second.
It'll continue slowing its spin rate as it falls and bounces off the ground.
Percents of how fast all this happens, Here's that same jump filmed from above and played back in real time.
So all of that footage was of a species that lives in and around the soil.
Some other springtails are semi-aquatic and you can find them on the surface of shallow ponds.
This is a temporary drainage pond in my neighborhood.
Every Spring, there's a mating aggregation of an aquatic species here.
They cover the surface, walking and jumping across the water.
Here's what an off-water jump looks like in slow motion.
That little speck at the bottom of the frame is one standing on water about to jump.
In midair, it completes 14 back flips while traveling a horizontal distance of over 14 body lengths.
And this one totally nails the perfect landing.
Some other jumps are not as graceful, and the springtails end up floating on the water in an awkward position.
When I filmed these off-water jumps up close and directly at the water level, you can see how when they flick their tales down, they aren't submerging them into water, instead the spring tail makes an indentation in the water surface and they actually push themselves forward and up and off the water.
Because these jumps hadn't been studied much, my initial research efforts are focused on gathering more of these clips like what I just showed you.
Further down the road, the research can address more advanced questions, like why are they spinning so fast in the first place?
And do these body rotations actually influence the flight path?
[soft marimba music] Regardless of what we find out, I think a lot of the importance of this type of research comes from being able to see and admire what these creatures are doing.
These are extraordinary organisms that are living their lives largely unnoticed right outside our doors.
So, next time you're outside, crouch down, flip over a leaf or two, and you're likely to find one of these things, but don't blink.
They might flick the tail, spin away, and disappear back into the soil.
- And that's it for Sci NC for now.
I'm Frank Graff.
Thank you for watching.
[bright electronic music] ♪ - [Frank] Want more Sci NC?
Visit us online.
- [Female Narrator] Additional funding for the Sci NC series is provided by GSK.
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