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Food energy is real energy, and it can be measured as such.

About ten years ago I started working out for the first time in my life, and with it, paying attention to the food I put in my body for breakfast, lunch, and dinner. I never knew much before that about calories, other than the tired "2000 a day" guideline. I could hardly tell you about macronutrients, or how much protein an active person should get. And so, later in my life, I had quite an education.

But there's still a lot that I don't know, apparently, because it wasn't until very recently that I learned where calories come from; or rather, how they're tallied up for inclusion on a food label. Of course, I am familiar with the idea that you can always count up the different ingredients in a meal and their known nutritional values. For example, if you're baking, it's easy to find out the calories in one cup of flour, a tablespoon of sugar, and so on.

But how are the calories in base foods even calculated? And furthermore, how do we know for sure how much protein, fat, or carbs are in certain foods?

It "blew" my mind when I learned that food scientists have a fascinating process for determining the amount of energy contained in different foods. It involves a strange machine called a "bomb calorimeter."


food, nutrition, calories, healthy eating, protein, fats, carbs, vitamins, minerals, eating, science, food scienceAn old bomb calorimeter from the 1960sSeth/Flickr

We all know that food gives us energy, but you've likely never thought of food energy in the same terms as the other different forms of energy like lights, heat, electricity, etc. I know I had never thought of it like energy energy.

But that's exactly what it is, and calories are a very specific measure of that energy.

So in order to determine how many calories are in a certain food, ingredient, or meal — get this — scientists literally blow it up and measure the results of the explosion.

How cool is that!?

In the video below, scientists from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University show the fascinating process from start to finish.

In the experiment, the team prepares a Christmas dinner plate of turkey, gravy, and potatoes. The first step to determining the calories in the meal is to "homogenize it" or blend it into smithereens, destroying any large chunks and turning the meal into a smooth, near-liquid. Yum!

"Then, over the course of three days we slowly remove all the moisture from it in a freeze drier," says Dr. Sue Roberts. Imagine turning that gooey slop into something similar to the consistency of astronaut food.

The dried samples are then compressed into extremely dense pellets about the size of a Tums antacid.

Now here comes the Parr 6200 "bomb" calorimeter. The very precisely measured pellet-ized portion of the original dinner is put into a chamber and lowered into some water inside the machine. An electrical charge is then applied to the food to "explode it."

Why the water? The calorimeter is able to measure the exact temperature of the water before and after the food explosion. When you look at the actual definition of a calorie, which according to Merriam-Webster is: "the amount of heat required to raise the temperature of one kilogram of water one degree Celsius," it all starts to make sense. Take the temperature of the water after the explosion and you can determine exactly how much energy was contained in the food pellet based on the temperature increase. Amazing!


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The calorimeter first came about in the 1800s. Even then, our understand of heat, energy, and food science was extremely limited.

As recently as the 1700s, scientists generally believed heat was made of some kind of weightless gas, which they called "caloric."

The theory was disproven in 1799 when Sir Humphrey Davy, an English chemist, rubbed two pieces of ice together in a vacuum (which contains no air or gas) and was able to generate friction heat, thus melting the ice. It was roughly around the same time that Antoine Lavoisier and Pierre Simon de la Place developed the first calorimeter.

Calorimeters, and the Calorie itself, weren't regularly used for food until the late 1800s.

As cool as it is (and it is extremely cool) exploding food in a bomb calorimeter isn't the most common practice today.

Frankly, it's usually not necessary when you can estimate nutritional values in other ways. More common today is the Atwater System, which estimates calories based on the nutritional breakdown of a food item as such:

  • Four kcals (calories) for one gram of protein
  • Four kcals for one gram of carbohydrates
  • Nine kcals for one gram of fat
  • Seven kcals for one gram of alcohol
All of these elements can be tested and measured in different, fascinating ways. Protein is counted by measuring the nitrogen released from food after putting it through some an artificial digestive process. Fats are measured by weighing the food, then stripping the fats away with ether, and weighing it again.

Carbs are the most complicated and thus are often measured by subtracting the percentage of proteins and fats. The remainders, by definition, should be carbohydrates.

food, nutrition, calories, healthy eating, protein, fats, carbs, vitamins, minerals, eating, science, food scienceThis food is on FIRE!Giphy

And, of course, bomb calorimeters have lots of different uses besides determining the calories in the newest line of flavored Doritos. They can be used to test the energy potential of alternative fuels, find more efficient animal feeds, and analyze samples of oil or coal for their potency.

Understanding this process kind of changes the way I look at food. You can't really see the energy in a bag of chips, let's say, but maybe you can imagine the way it might heat a pot of water if it exploded! It makes the numbers on the back of a nutritional label a little more tangible and real, and can maybe lead to more mindful and intuitive eating practices.

Ultimately, though, there is so much more to food than the calories it contains. There are the nutrients, like the proteins, carbs, and fats — the micronutrients like vitamins and minerals that our bodies need. Some people like to know as little as possible about the inner workings of our food and focus purely on their enjoyment of the making, eating, and sharing. But if you're like me, you like to know the science behind food production, and how and why food powers our bodies the way it does. That's all part of the fun.

Conservation

People are dumbfounded when they learn this little known secret to burning candles correctly

There's an art to avoiding the "memory ring" that makes a candle tunnel around the wick.

Photo by Jessica Mangano on Unsplash
The "tunnel" that often forms around a wick isn't supposed to be there.

The evolution of candles from lighting necessity to scented ambience creator is kind of funny. For thousands of years, people relied on candles and oil lamps for light, but with the invention of the light bulb in 1879, fire was no longer needed for light. At that time, people were probably relieved to not have to set something on fire every time they wanted to see in the dark, and now here we are spending tons of money to do it just for funsies.

We love lighting candles for coziness and romance, relishing their warm, soft light as we shrink from the fluorescent bulb craze of the early 2000s. Many people use candles for adding scent to a room, and there are entire candle companies just for this purpose (Yankee Candles, anyone?). As of 2022, candles were an $11 billion business. Michael Scott once said they're the number one fastest growing product in the scent aroma market.

candle burning, candles, aroma, scent, homemaking, home, diy hacks, diy, life hacksBonfire, James Bonfire!Giphy

With their widespread use, you'd think we'd know a thing or two about candles, but as it turns out, a whole bunch of us have been burning candles wrong our entire lives without knowing it.

A recent post on Twitter X started the education session:

"Just learned that my fiancé, who buys candles all the time and we literally always have candles burning, did not actually know how they work and blew out a medium first burn candle 30 minutes after I lit it when I wasn’t paying attention and ruined it," the user wrote.

Many people had no idea what she was talking about. In fact, the original since-deleted post went viral with hundreds of people asking: Huh? So the OP explained.

"If a candle is not burned for long enough on first burn to melt edge to edge it will create a 'memory ring.' Once a candle has a memory ring, it will continue to tunnel and never burn all the way across."

Now THAT'S something almost everyone has experienced. Candles are pretty expensive, so it's frustrating when all that delicious-smelling wax gets left behind. Apparently, a short first burn (in this case, just 30 minutes) is one of the main culprits of a ruined candle.

Tunneling is the name of the phenomenon where a narrow tube-shaped area of candle continues to burn deeper and deeper, leaving lots of "waste" wax around its edges. Experts agree that the first burn should last 2-4 hours at least to avoid an uneven or narrow memory ring. (But don't burn a candle for over 10 hours at a time or you risk too much carbon buildup on your wicks.)

"If a candle is not burned for long enough on first burn to melt edge to edge it will create a 'memory ring.' Once a candle has a memory ring, it will continue to tunnel and never burn all the way across."

candle burning, candles, aroma, scent, homemaking, home, diy hacks, diy, life hacksWitches must have really known the ins and outs of candle burning.Giphy

"This is why you should not light a large candle at night, which is unlikely to burn all the way across before you need to blow out to go to bed. Allow at least one hour per inch of candle width," she went on.

So that's why candles always end up with a hole in the middle, making us think the candle companies are just running a scam to make us go through candles faster. Nope. It's user error, and many people were flabbergasted by this realization.

"This is the most useful information I’ve been given my entire adult life," wrote one person.

"This skill should be taught in schools," shared another. "The amount I’ve wasted on half burnt candles is outrageous, the amount of times I’ve used Algebra since leaving school = 0."

"When I worked at Pier 1 in the 90s I got to go to some candle workshop that taught us the correct way to use (and therefore sell) candles and that is probably some of the most useful knowledge I've carried in my head this long life," shared another.

Well, never say 'never,' because here's the good news: a tunneled candle can be fixed!

Probably the easiest way is to avoid tunneling your candles in the first place by burning them long enough upon first burn to liquify the entire top layer of wax. Again, that's usually 2-4 hours.

It also helps to care for the wicks regularly! Good wicks allow for a clean, even burn. Trim the burnt ends before lighting the candle and, if possible, use a snuffer instead of blowing out the flames with your mouth. Using a candle warmer is another way to get an even melt; with the added perk of making the scented wax last much, much longer.

But even if you do accidentally "ruin" a candle, it can be recovered. Placing a ring of foil around the candle with just a small opening at the top for the flame will help trap heat and help the edges of the wax melt on the next burn. Once the memory ring evens out, you can burn the candle like normal again.

(In fact, you can even use a candle warmer to melt the wax back to even and then resume burning. Some clever candlers even put candles on the hot pad of their coffee makers as a DIY hack.)

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The candle posts also prompted a separate discussion about candles and indoor air quality and the volatile organic compounds that are released when they are burned.

Some people equated burning candles with having a small engine running in your living room, though according to the Cleveland Clinic, there's scant evidence that the amount of toxins released by burning candles is actually hazardous to your health, especially if you use high quality candles in a well-ventilated area.

candle burning, candles, aroma, scent, homemaking, home, diy hacks, diy, life hacksDon't worry, a tunneled candle can be recovered again. Photo by Rebecca Peterson-Hall on Unsplash

How do you know if a candle is "high quality"? First, check the wick for metal. Lead in wicks is not nearly as common as it used to be, but best not to risk it if you find metal in the wick. Second, choose soy, beeswax, palm or coconut wax candles instead of paraffin, which is petroleum-based product and more likely to put off soot and smoke particles. Everyone reacts differently to different amounts of particulates in the air, so if you find yourself getting headaches or respiratory symptoms when using candles, it's probably best to avoid them.

But if you tolerate them, feel free to enjoy as recommended,—just make sure that first burn melts the wax all the way to the edges to avoid the dreaded tunneling.

This article originally appeared last year. It has been updated.

An image of a great glider

When a team of Australian researchers started checking the high-tech boxes they'd installed to help save endangered greater gliders back in 2023, they weren't sure what they were going to find. The hope was that the tree-dwelling marsupials would use them for nesting—a replacement for the tree hollows they normally nest in—but no one knew whether or not the creatures would take to them.

So when Dr. Kita Ashman, Threatened Species and Climate Adaptation Ecologist at WWF-Australia, found a glider in the second box she checked, she was thrilled.

"I just burst into tears, I was so surprised and so happy," she told ABC News Australia.

Greater gliders are nocturnal marsupials that live in old-growth forests of eastern Australia. They have large ears, fluffy fur, long tails, and they can glide up to 100 meters at a time. The species is only found in Australia.

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"I grew up looking at greater gliders all throughout the Dandenong Ranges. So they have a really special place in my heart," said Dr. Ashman told ANU.

The special nesting boxes were designed and created through a partnership between Australian National University (ANU), Greening Australia and the World Wide Fund for Nature-Australia after 2019-2020 bushfires destroyed a third of the greater gliders' remaining habitat. The tree hollows that greater gliders rely on to nest can take over 100 years to form, according to ANU, so it's not like they can just find some new trees to live in when their homes are destroyed.

Nesting boxes that are commonly used for wildlife aren't a good fit for greater gliders, as the thin walls and lack of thermal protection can result in gliders overheating. (Heat-stressed gliders will slow their eating, which can be life-threatening, according to ANU.) The high-tech boxes in this project are insulated and include a non-toxic, heat-reflective, fire-resistant coating to keep gliders safe.

"I've affectionately been calling this design the Goldilocks box because we hope it will keep greater gliders not too hot and not too cold and will help to increase the species' resilience in a changing climate," Ashman said in July 2022.

"Producing and installing high-quality nest boxes is costly," added ANU research fellow Dr. Kara Youngentob, "so this project is very important because it will help us understand if expensive interventions like nest boxes are the best use of funding in our urgent mission to save greater gliders."

It appears that their efforts are paying off.

"What we didn't know was whether these boxes worked and whether they have an impact on the glider population," Dr. Youngentob told ABC News Australia. "Much to our delight, within a few months of them going up they are already being used by gliders, so we know the individuals themselves like them and use them."

According to Youngentob, greater gliders are the largest gliding marsupial at risk of extinction. More than 200 nesting boxes have been installed in Victoria's East Gippsland and in Tallaganda National Park in New South Wales. Youngentob told ABC News Australia that this project will help researchers learn more about how many of the species are left in the wild.

The quiet, nocturnal marsupial faces threats from climate change and deforestation in addition to the wildfires that ravaged Australia in 2020. Their population has fallen by 80% in the past 20 years and the species has maintained an endangered status since July of 2022.

greater gliders, great gliders endangered, australian animals, endangered animals, endangered australian animals, world wildlife fundAn image of two greater glider on a treePhoto credit: Canva

"They're a treasure for this country." Dr. Youngentob told ANU. "And I think the more people know about them, the more that they will fall in love with them and want to protect them too."

This article originally appeared two years ago

Animals & Wildlife

Why have we domesticated some animals but not others? It comes down to four F's.

An entertaining video explains why we can't ride zebras or breed "war bears."

Horses were domesticated over 5,000 years ago. Zebras, never.

Humans have domesticated several kinds of animals over the millennia, from trusty horses and mules to livestock for milk and meat to our favorite furry companions. But why those specific animals and not others? What is it that led us to those particular choices? Why can we ride horses but not zebras? Why don't we purposefully breed "war bears" to fight for us?

That last question comes straight from the always-interesting and often-hilarious CGP Grey, whose YouTube videos explore all kinds of things we wonder about but don't necessarily take the time to research. In the video "Why Some Animals Can't Be Domesticated," Grey explains the four main elements that make an animal a good candidate for domestication, which excludes bears (and many others) from the list.

Grey alliterated the four elements to make them easier to remember: Friendly, Feedable, Fecund, and Family-Friendly. Let's dig into what those mean.

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Domestication requirement #1: Friendly

This one is fairly self-explanatory, but basically an animal has to not post an inherent, immediate threat. We have to be able to catch them if we're going to domesticate them, so that eliminates all of the "carnivores whose day job is murder" as Grey puts it, as well as the large, nervous prey animals that are too afraid of us to let us get anywhere near them.

wild animals, domesticated animals, gazelleGood luck trying to catch a gazelle.Photo credit: Canva

Domestication requirement #2: Feedable

Every animals is feedable, of course, but that doesn't mean it's easy or cheap to feed them, especially in large numbers. This category pretty much eliminates pure carnivores and some omnivores, leaving mostly herbivores (and some unpicky omnivores) that are easy and cheap to feed. And that aren't dangerous (see #1).

wild animals, domesticated animals, chickens, chicken feedChickens will eat just about anything.Photo credit: Canva

Domestication requirement #3: Fecund

This requirement is all about breeding and babies. Some animals are extremely slow to breed, like pandas and elephants, making them undesirable candidates for domestication. Animals that have mate frequently and have relatively short gestation times and/or large litters are more suited to domesticated life. They also need to grow up quickly, which also takes elephants out of the pool.

However, as Grey points out, humans can still tame other animals like elephants. But taming is not the same as domesticating. The basic rule is: If it's on a farm, it's domesticated. If it's in a circus, it's tamed.

Domestication requirement #4: Family-friendly

This is where the horses and zebras question comes in. Horses were domesticated in Eurasia, but if humans started in Africa, why weren't zebras domesticated first? Grey explains that while horses tend to live in hierarchical herds, zebra are more independent with no family structure. Humans can capture the lead male horse and get the rest of the herd to fall in line. Zebra herds are more of a free-for-all and they're kind of jerks to even one another.

horses, zebras, domesticated animals, wild animalsThere's actually a big difference between horses and zebras besides just the stripes.Photo credit: Canva

Barnyard animals have inherent family structures that humans have figured out how to fit into. These animals learn to see the humans who own them as a lead cow or top chicken or whatever.

Way back in the hunter-gatherer age, when humans were just figuring out animal domestication, animals had to have all four of these requirements. Today, we have the ability and technology to domesticate more animals if we want to, but we also have less of a need to. Some breeds of foxes have recently been domesticated, bred to be friendly with humans. How fun would it be to have a pet fox?

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Technically, a lot more animals could be domesticated if people really wanted to put in multiple human lifetimes of time and effort, but why?

You can follow CGP Grey on YouTube for more fun and informative videos.

This article originally appeared in April.