Nuclear Bomb vs. Dirty Bomb: What's the Difference?

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iStock

The Quick Trick: If you're standing in an absolute wasteland amid thousands of corpses, it was a nuclear bomb. If you're standing in a normal city street amid a moderate amount of inconvenience, it was a dirty nuclear bomb.

The Explanation: Here is the primary difference: Nuclear bombs have, in the past 70 years, killed hundreds of thousands of people. Dirty nuclear bombs have, in all of human history, killed exactly no one—partly because they aren't terribly dangerous and partly because not one has ever been detonated.

Conventional nuclear weapons get their explosive power from either nuclear fission or fusion. The bombs dropped on Hiroshima and Nagasaki—the only nuclear weapons that have been used in warfare—were both fission bombs. Fusion bombs, sometimes called hydrogen bombs, are even more powerful—the U.S. once detonated a 15-megaton fusion bomb in a test. That's approximately 100 times more powerful than "Little Boy," the nuclear weapon dropped on Hiroshima that instantly killed 100,000 people. Most modern bombs combine fission and fusion: a small fission bomb is used to create heat adequate to fuel the
fusion.

Even with the physics know-how, the bombs require exceedingly rare isotopes of either plutonium or uranium. The process of getting the elements to the necessary isotope is known as enrichment, and enrichment is generally the stumbling block for nations looking to join the nuclear club. It was even a challenge for the U.S.: Almost 90 percent of the Manhattan Project's budget was spent enriching uranium.

In short, nuclear weapons are extremely difficult to make—and we hope they always will be. A dirty nuclear bomb, on the other hand, could be made by a reasonably smart 14-year-old with access to hospital equipment. Dirty bombs combine conventional explosives (say, dynamite) with radioactive materials (say, cesium, which is used in radiation treatment for cancer patients). Almost all scientists believe that even in the case of a well-designed dirty bomb, the explosive would cause much more damage than the radiation. The fact is there just aren't any acquirable materials radioactive enough to cause much fallout. And while it could be very expensive and inconvenient to clean up an urban area after a dirty bomb attack—that's about it. The difference between the two is that conventional nuclear weapons are infinitely more worrisome.

Dirty Secrets
The only recorded attempt to detonate a dirty bomb came in 1995, when Chechen rebels—who had been on the forefront of terrorism techniques since the Soviet Union's breakup—called reporters to say they'd planted a bomb in a Moscow park. Made of dynamite and cesium taken from a cancer treatment center, the dynamite might have killed people, but its cesium would have been just the equivalent of a few X-rays for those walking past the park. Regardless, the bomb was defused before it exploded.

Why Is Pee Yellow?

Chloe Effron
Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Your body is kind of like a house. You bring things into your body by eating, drinking, and breathing. But just like the things we bring home to real houses, we don’t need every part of what we take in. So there are leftovers, or garbage. And if you let garbage sit around in your house or your body for too long, it gets gross and can make you sick. Your body takes out the garbage by peeing and pooping. These two things are part of your body’s excretory system (ECKS-krih-tore-eee SISS-tem), which is just a fancy way of saying “trash removal.” If your body is healthy, when you look in the toilet you should see brown poop and yellow pee.

Clear, light yellow pee is a sign that your excretory system and the rest of your body are working right. If your pee, or urine (YER-inn), is not see-through, that might mean you are sick. Dark yellow urine usually means that you aren’t drinking enough water. On the other hand, really pale or colorless pee can mean you might be drinking too much water! 

Your blood is filtered through two small organs called kidneys (KID-knees). Remember the garbage we talked about earlier? The chemicals called toxins (TOCK-sins) are like garbage in your blood. Your kidneys act like a net, catching the toxins and other leftovers and turning them into pee.

One part of your blood is called hemoglobin (HEE-moh-gloh-bin). This is what makes your blood red. Hemoglobin goes through a lot of changes as it passes through your body. When it reaches your kidneys, it turns yellow thanks to a chemical called urobilin (yer-ah-BY-lin). Urobilin is kind of like food coloring. The more water you add, the lighter it will be. That's why, if you see dark yellow pee in the toilet, it's time to ask your mom or dad for a cup of water. 

To learn more about pee, check out this article from Kids Health. 

Scientists Discover How to Snap Spaghetti Into Two Perfect Pieces

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iStock

Important news for pasta lovers: Researchers at MIT just figured out how to snap a strand of spaghetti into two perfect pieces, according to New Scientist. The days of having to sweep up the tiny fragments that fly in all directions when you break spaghetti into two pot-ready portions are over.

In 2005, researchers in France figured out why spaghetti cracks into bits: The strand flexes in the opposite direction after the initial snap, creating a “snap-back effect” that causes it to break a second time.

Now, after snapping hundreds of spaghetti sticks, MIT mathematicians have the solution. The researchers used a pair of clamps to twist individual strands of spaghetti almost 360 degrees. Next, the two clamps were slowly brought together to bend the stick, resulting in a perfect fracture. This worked for two kinds of spaghetti with different thicknesses—Barilla No. 5 and Barilla No. 7, to be precise.

The process was recorded using a high-speed camera (which can be viewed on MIT's website). While reviewing the footage, researchers realized that adding a twist is key because it prevents the spaghetti stick from forcefully flexing backwards. Their findings were published in the Proceedings of the National Academy of Sciences.

Even without equipment, you can can try this at home. It might take a bit of practice, though, so have a couple of boxes handy. Ronald Heisser, a former MIT student who is now a graduate student at Cornell University, came up with the technique for how to manually snap spaghetti in two.

“I would start with my hands opposite each other—one hand upside down and the other right side up—and then make both of them right side up while twisting the spaghetti so you can work your arm strength into it,” Heisser tells Mental Floss.

“You know you're twisting it right when you feel it really trying to untwist itself. Then, you can carefully bring the ends together, trying not to change the twist at all.”

He noted that your hands should also be dry, because oiliness can make the strand slip in your fingers.

However, it's unlikely that anyone has the patience to sit there and snap one strand of spaghetti at a time. So does this trick work for a whole handful of pasta? Dr. Jörn Dunkel, who led the study, says it’s difficult to predict how a handful of spaghetti would fracture, but he believes this technique would reduce the number of pieces you end up with.

“When many spaghetti [strands] become bunched together, they can transfer energy between them, which can change their bending and fracture behavior significantly,” Dr. Dunkel tells Mental Floss. “Very roughly, as a rule of thumb, one would expect that splitting the energy between bending and twisting should always help to reduce the fragment number compared to pure bending.”

Of course, if you want to cook the true Italian way, you’ll leave your spaghetti unsnapped and intact. (Longer pasta is said to wrap around your fork better, making it easier to eat.)

But if you want to try this bend-and-snap technique for yourself, the purists would probably give you a pass.

[h/t New Scientist]

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