Simple Experiments Show How Motion Is Equivalent to Heat

Some of the most difficult (and most important) experiments in the history of physics had to do with making connections between different concepts. What about the connection between objects moving around (kinematics) and objects changing temperature (thermodynamics)? That was a tough one. It’s called the mechanical equivalent of heat and it was explored in 1868 by James Joule.

The basic idea was to have a mass that moves down due to the gravitational force. This mass is attached to a string that connects to a spinning paddle in a container of water. As the mass moves down it spins the water and adds energy to it—hopefully increasing the temperature. The change in gravitational energy of the mass should be equal to the change in thermal energy of the water.

OK, we actually already know this relationship. But it’s still fun to reproduce it. To do that, first we need to know about the different forms of energy. First there is the gravitational [...]  read more

The Mysterious Math of How Cells Determine Their Own Fate

In 1891, when the German biologist Hans Driesch split two-cell sea urchin embryos in half, he found that each of the separated cells then gave rise to its own complete, albeit smaller, larva. Somehow, the halves “knew” to change their entire developmental program: At that stage, the blueprint for what they would become had apparently not yet been drawn out, at least not in ink.

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Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

Since then, scientists have been trying to understand what goes into making this blueprint, and how instructive it is. (Driesch himself, frustrated at his inability to come up with a solution, threw up his hands and left the field entirely.) It’s now known that some form of positional information makes genes variously switch on and off throughout the embryo, giving cells distinct identities based on their location. But the signals carrying that information seem to fluctuate wildly and chaotically—the opposite of what you might expect for an important guiding influence.

“The [embryo] is [...]  read more

Costa Rica’s Zero-Carbon Plan Could Be a Model for the World

Carlos Alvarado Quesada has heard all the naysayers before. In February, the 39-year-old president of Costa Rica committed to ridding the country of fossil fuels by 2050. If successful, Alvarado’s plan could make Costa Rica the first zero-emissions country.

With a population of merely 5 million, this leafy Central American nation is not a major contributor to the world’s climate crisis. So why bother then? “People ask me a lot, why do this if you are so small,” Alvarado said in a meeting last week with editors at WIRED’s San Francisco office. “They say, you’re not going to move the needle or affect the scale of the problem.” China, the US, and India hold the dark distinction of leading the emissions charts, and the top 10 emitters account for almost 70 percent of greenhouse gasses. Costa Rica’s emissions barely register in the global carbon belch-athon that’s throwing the climate into disarray.

But Alvarado—who [...]  read more

Those Midwestern Floods Are Expected to Get Much, Much Worse

The record-setting floods deluging the Midwest are about to get a lot worse. Fueled by rapidly melting snowpack and a forecast of more rainstorms in the next few weeks, federal officials warn that 200 million people in 25 states face a risk through May. Floodwaters coursing through Nebraska have already forced tens of thousands of people to flee and have caused $1.3 billion in damage.

The National Oceanic and Atmospheric Administration issued its spring flood outlook Thursday, predicting that two-thirds of the country is at risk of “major to moderate flooding,” from Fargo, North Dakota, on the Red River of the North down to Nashville, Tennessee, on the Cumberland River. The floods from the past two weeks have compromised 200 miles of levees in Nebraska, Iowa, Missouri, and Kansas, according to the US Army Corps of Engineers.

The rains and floods are expected to continue through May and become more dire, according to Ed Clark, director of NOAA’s National Water [...]  read more

You Can Play With Escape Velocity—Without Leaving the Planet

If you like cool-sounding science terms, escape velocity should fit the bill. But what the heck does it even mean? Allow me to explain.

Surely, you have heard this before:

What goes up, must come down.

How about an experiment to see if this is even true? I’m going to take a ball and toss it up. Let’s see what happens. You can try this at home.

Rhett Allain

That seems to work. What if I throw it even higher?

Rhett Allain

It still works. It goes up. It comes down. But why? Here is a force diagram for the ball right after I throw it up.

Rhett Allain

Since the ball is moving upward, I put a dashed arrow to represent the velocity. I just want to point out that velocity is not a force. The real force is the downward “mg” arrow. This is the force due to the gravitational interaction between the Earth and the ball. In this case, the force depends on the mass of the ball (m) and the local gravitational field (g) with a value of around 9.8 Newtons per kilogram.

But [...]  read more

Finally! A DNA Computer That Can Actually Be Reprogrammed

DNA is supposed to rescue us from a computing rut. With advances using silicon petering out, DNA-based computers hold the promise of massive parallel computing architectures that are impossible today.

But there’s a problem: The molecular circuits built so far have no flexibility at all. Today, using DNA to compute is “like having to build a new computer out of new hardware just to run a new piece of software,” says computer scientist David Doty. So Doty, a professor at UC Davis, and his colleagues set out to see what it would take to implement a DNA computer that was in fact reprogrammable.

As detailed in a paper published this week in Nature, Doty and his colleagues from Caltech and Maynooth University demonstrated just that. They showed it’s possible to use a simple trigger to coax the same basic set of DNA molecules into implementing numerous different [...]  read more

Cannabis: The Complete WIRED Guide

Humanity just can’t make up its mind about cannabis. For thousands of years, humans have used the stuff as medicine or to travel on spiritual quests. That, though, didn’t quite suit the British, who banned cannabis in colonial India. Then in the 20th century, the United States government declared war on marijuana, and most of the world followed suit.

But today, state after state is calling out the federal government on its absurd claim that weed should be a schedule I drug—an extreme danger with no medical benefits—and should fall in the same category as heroin. Even on the federal level, congressional reps like Elizabeth Warren are fighting to end the criminalization of cannabis use. The fact is, scientists have proven cannabis can treat a range of ills and that it’s actually much safer than alcohol. The twisty-turny journey of cannabis has landed us back at a central truth: It’s actually a powerful medicine that can help treat what ails the human body.

Matt Simon covers cannabis, robots, and climate science for WIRED.

Yet [...]  read more

The Youth Climate Strike as Seen by Teen Photographers

On the steps of the Georgia State Capitol building in Atlanta, students chanted in unison.

The vibe at the Atlanta Youth Climate Strike was serious, but hopeful, says 17-year-old photographer Esme Bella Rice.

Students leave Henry W. Grady High School in Atlanta to join the climate strike.

“The age diversity was really cool,” says Rice.

As Atlanta drivers passed on Washington Street, students held signs like “Respect Your Mother.”

“The feeling was both hopeful and so serious,” says Rice. “You think, ‘Wow, this is our reality,’ but then you remember that they are out there fighting for it, and it’s hopeful because it’s such a strong generation already.”

Students cheer in Atlanta. Organizers there passed around chant sheets so everyone knew what to say.

A very young boy in Atlanta holds a sign that reads “School Strike for Climate.”

Even after the students left–many to go back to school–their signs remained [...]  read more

A More Humane Livestock Industry, Brought to You By Crispr

Hopes were running high for cow 401, and cow 401 serenely bore the weight of expectations. She entered the cattle chute obligingly, and as the vet searched her uterus, making full use of the plastic glove that covered his arm up to his shoulder, she uttered nary a moo. A week ago, Cow 401 and four other members of her experimental herd at UC Davis were in the early stages of pregnancy. But now, following a string of disappointing checkups, it was all down to her. Alison Van Eenennaam, the animal geneticist in charge of the proceedings, kept watch from off to one side, galoshes firmly planted in the damp manure, eyes fixed on a portable ultrasound monitor. After a few moments, the vet delivered his fifth and final diagnosis. “She’s not pregnant,” he said. Van Eenennaam looked up. “Ah, shit,” she muttered.

Cow 401 and her herdmates were the product of two and a half years of research, Van Eenennaam’s attempt to create a strain of gene-edited cattle specially suited to the needs of the beef industry. Had everything gone as planned, all the calves in this experiment would have been born male—physiologically, at least. Like humans, cattle carry two sex chromosomes; those born XX are female, and those born XY are male. But it isn’t the Y that makes the man. It’s a single gene, called SRY, that briefly flickers to life as an embryo grows and instructs it to develop male traits. Using Crispr, Van Eenennaam’s team added a copy of SRY to the X chromosome too. That way, even if a cow was born genetically female, she’d be expected to appear male all the same. Since beef ranchers generally prefer males to females (more meat for the money), Van Eenennaam believed there could someday be a market for these Crispr’d animals.

Christie Hemm Klok

More than that, though, the project was a proof of concept. One [...]  read more

Women’s Pain Is Different From Men’s—the Drugs Could Be Too

Men and women can’t feel each other’s pain. Literally. We have different biological pathways for chronic pain, which means pain-relieving drugs that work for one sex might fail in the other half of the population.

So why don’t we have pain medicines designed just for men or women? The reason is simple: Because no one has looked for them. Drug development begins with studies on rats and mice, and until three years ago, almost all that research used only male animals. As a result, women in particular may be left with unnecessary pain—but men might be too.

Now a study in the journal Brain reveals differences in the sensory nerves that enter the spinal cords of men and women with neuropathic pain, which is persistent shooting or burning pain. The first such study in humans, it provides the most compelling evidence yet that we need different drugs for men and women.

“There’s a huge amount of suffering that’s happening that we could solve,” says Ted Price, [...]  read more