Learn about how screeching tape travels at supersonic speeds when you peel it; how Americans are aging more slowly than ever; how the HAMMER spacecraft could save our planet from killer asteroids; and why there are mirrors next to elevators.
Learn about how screeching tape travels at supersonic speeds when you peel it; how Americans are aging more slowly than ever; how the HAMMER spacecraft could save our planet from killer asteroids; and why there are mirrors next to elevators.
How screeching tape travels at supersonic speeds by Cameron Duke
The first ever episode of Curiosity Daily: https://curiositydaily.com/0423-daily/
Americans Are Aging More Slowly Than Ever by Reuben Westmaas
The HAMMER Spacecraft Could Save the World from Killer Asteroids by Elizabeth Howell
There Are Mirrors Next to Elevators for a Specific Reason by Joanie Faletto
Subscribe to Curiosity Daily to learn something new every day with Cody Gough and Ashley Hamer. You can also listen to our podcast as part of your Alexa Flash Briefing; Amazon smart speakers users, click/tap “enable” here: https://www.amazon.com/Curiosity-com-Curiosity-Daily-from/dp/B07CP17DJY
Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/anniversary-episode-supersonic-packing-tape-chronological-vs-biological-age-why-mirrors-are-next-to-elevators-and-anti-asteroid-spacecraft
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about how screeching tape travels at supersonic speeds when you peel it. Then, you’ll get a grab bag of three more stories when we do a special throwback. It’s our way of celebrating today, which is the 2-year anniversary of the first episode of Curiosity Daily.
CODY: Happy anniversary, us! Let’s satisfy some curiosity.
I’m moving into a new home in about a month, so I’ve been packing my stuff for at least 3 weeks now. Which means that maybe this question is a little biased, but I’ve gotta ask: have you ever wondered why packing tape is SO DARN LOUD? To find out, you have to get down to the microscopic level. I don’t really have the means to do that, but fortunately, a group of physicists did — and the results are incredible. It turns out that if tape were a fighter jet, it would break the sound barrier.
When you peel tape to, say, pack a moving box, or assemble Amazon boxes into a Transformer costume called “Amazon Optimus Prime,” you probably notice two things. For one, peeling tape is noisy. Second, it’s hard! You pull a little bit, and nothing happens. Then you pull harder, and too much tape comes off. You might call this annoying, but scientists call it “macroscopic stick-slip.” It might seem minor in the scheme of things. But in certain contexts, like a warehouse environment, this constant screeching could potentially lead to hearing damage.
The weird thing is that scientists didn’t fully understand how the tape makes that sound, so a team of them decided to take a closer look. Like, way up close. With a microscope. They peeled some tape while recording microscopic footage with a high-speed camera that filmed at 300,000 frames per second.
They found that tape is just as finicky on the microscopic level as it is on the macroscopic level. It doesn’t peel smoothly; instead, it detaches in a bunch of little lines that lie perpendicular to the direction you’re peeling. But these lines don’t just appear one after the other; instead, each one races from one side of the tape to the other at around twice the speed of sound. The scientists call those crack fronts. Each one represents potential energy in the tape being converted into kinetic energy, like tiny springs being released. The screeching is the sum of thousands of these little releases.
The scientists still have a lot to learn, and not least of all is why those crack fronts happen. But their research goes way beyond just understanding how tape peels. That knowledge could shed light on other rapid, self-propagating fracture processes, like earthquakes. So the next time your packing tape screeches, don’t cover your ears. Just enjoy the sound of physics in action.
ASHLEY: We published the first episode of Curiosity Daily 2 years ago today. We’d already been doing a weekly podcast that we launched in 2017, so between the original Curiosity Podcast and Curiosity Daily, we’ve published more than 600 episodes.
[ad lib]
ASHLEY: As you might guess, we’ve changed some things since we first launched.
CODY: I have a comment
ASHLEY: So we thought it would be fun to play our first episode, right now, so you can hear how we’ve changed. We’ll talk about it afterwards. Here it is!
[CLIP 5:45] https://curiositydaily.com/0423-daily/
CODY: OH BOY [ad lib]
Let’s do a quick recap of what we learned today
[ad lib optional]
CODY: Today’s stories were written by Cameron Duke, Reuben Westmaas, Elizabeth Howell, and Joanie Faletto, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Today’s episode was produced and edited by Cody Gough.
CODY: Join us again tomorrow for the beginning of our THIRD year of Curiosity Daily, to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!