16 Nov 2018

A Slice of Science

By Simon Shapiro

Watching "The Great British Baking Show" recently, I was intrigued by the judges' comments. They would glance at piece of bread and immediately say
"You proofed it for too long" (or not long enough)
"You kneaded it too much" (or not enough)
"Overbaked" (or underbaked)
"Oven was too hot" (or too cool)
"The wrong flour"
"Too much liquid"

They really seemed to know all about the process and what can go wrong. (It sounded complex and lots could go wrong).

That led me to wondering about the science behind baking bread. Humans have been baking bread for thousands of years. At its simplest, all you do is mix flour and water, and bake it. But it gets more complicated and there's a lot of science involved.

Nathan Myhrvold, a physicist and former Microsoft Chief Technology Officer, founded Intellectual Ventures Lab, which performs scientific experiments with food. Last year they published Modernist Bread, a 6-volume 2642-page book about bread. It reflects information from 1,600 experiments.

Want more dough? As for a raise. 

Flour and water and 18 minutes of baking will get the flat bread called matzah.  Most people who eat this for a week find it boring, to say the least. Comparisons to cardboard are common.

Jews are required to eat matzah and no leavened bread for the seven days of the Passover festival.

The easiest and quickest leavened bread is soda bread. You make this by adding baking soda or baking powder to the mix. Baking soda is simply sodium bicarbonate (NaHCO3). When it's mixed with an acid, the reaction releases carbon dioxide gas. Common acids in bread recipes include cream of tartar, lemon juice, yogurt, buttermilk, cocoa and vinegar. You have to get the right balance of acid and baking soda. If you have too little acid, unreacted baking soda will taste metallic and bitter. Baking powder makes life easier. It consists of baking soda pre-mixed with dry acid. Adding liquid is all you need to add to get little bubbles of gas. (See it for yourself: add water to some baking powder and watch it fizz; add water to some baking soda - no fizz until you add lemon juice).

It's not as quick and easy, but  using yeast to get the carbon dioxide bubbles tastes better and is more versatile for getting different bread textures. Yeast is a single celled fungus that feeds on sugar and transforms it into alcohol and carbon dioxide gas.

Yeast cells at a magnification of 400
  Where does the sugar come from? Adding water to flour allows enzymes in the flour to convert starch within the flour into sugars.

What else do we need?

We need some sort of framework to capture the carbon dioxide bubbles. The best material for this is gluten. Gluten consists of long, elastic protein chains, which form rubbery networks, perfect for capturing gas. It's a lot like a balloon. Handily, wheat flour contains two proteins, glutenin and gliadin which, when combined with water, form gluten.

 The more protein in the flour, the more gluten it has. That's why cake flour and bread flour are different. Bread needs much more gluten than cakes do. Bread flour has about twice as much protein as cake flour. This video


has a great demonstration of the difference and really shows the elastic property of gluten.

Most bread recipes mix the dry and wet ingredients and then leave the dough for an hour or two to do its magic: breaking down the starch to form sugar, which feeds the yeast cells, giving off bubbles of carbon dioxide which are captured in the gluten network. The dough will rise to about double its original volume. This is called proofing.

Then you knead the dough by repeatedly folding at and squashing it. This helps develop the gluten network to make it stronger and more elastic. Some recipes repeat the process of letting the dough rise and kneading it - sometimes several times.

Now we're cooking!

It's time to bake. As the dough heats up in the oven, the carbon dioxide bubbles expand. New bubbles are also formed because the alcohol (remember that yeast produces both carbon dioxide and alcohol) and the water which the starch absorbed, both vaporize. So the dough rises again. This is called "oven spring".

Illustration of heat transfer from Modernist Bread, The Cooking Lab
Heat is transferred from the outside of the loaf through "heat pipes". Adjacent bubbles transfer heat from the outer side by water boiling on that side and steam condensing on the inner side, releasing heat to start vapourising the next bubble in the "pipe". The rising heat kills the yeast cells, hardens the gluten network and caramelizes sugars on the crust of the loaf.

If the experiment was successful, you now have a hot, crusty, delicious loaf of bread.

Full disclosure: I haven't yet put any of my newly discovered information to the test of actually baking bread. But I will!


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9 Nov 2018

The Woman Who Loves Giraffes





The Woman Who Loves Giraffes PosterI recently had the opportunity to attend a screening of The Woman Who Loves Giraffes,  a biopic about Anne Innis Dagg, a groundbreaking Canadian biologist who was the first to document much of giraffe behavior and ecology. Much like her better-known peers, Dian Fossey and Jane Goodall, Dagg pioneered the observational techniques of animal study, spending hours every day watching and recording every detail of giraffe behavior. Her story is fascinating, and so is she!

Dagg wrote a wonderful children’s books about her life: 5 Giraffes, published by Fitzhenry and Whiteside. It was the 2017 winner of the Lane Anderson Award for Science Writing for Children.  

If you have the opportunity to see the movie, go! It’s great! Here’s the link to the film deets and showings. https://thewomanwholovesgiraffes.com/  



10.Anne Innis Dagg feeding giraffe.jpg

26 Oct 2018

This is Your Brain on Cannabis

Teens who use pot have to engage more
brain resources to complete complex tasks.
By L. E. Carmichael

Confession: I recently tried cannabis for the very first time. My back had been in spasm for five days - five days in which I'd levelled up from hot baths and ibuprofen to prescription anti-inflammatories to prescription narcotics, without even the slightest improvement. I had three days more days to go before I could get in to see a therapist, so in desperation, I tried the pot.

Why had I waited until I was 40 to do a thing a lot of people experience as teenagers? First of all, until last Wednesday (October 17, 2018), cannabis was illegal in Canada. Second of all, I am "the smart girl" and have been my entire life. Being "the smart girl" - and a writer - requires a functioning brain, and the idea of deliberately ingesting things that could mess with my brain made me deeply uncomfortable.

So what does science tell us about the impact of cannabis on the brain?

There aren't a lot of conclusive studies, in part because it's hard to do controlled research on illegal substances. Our knowledge will probably improve over the next few years. That said, the data we do have on impacts of young brains is troubling, to say the least.

Studies suggest that smoking pot during pregnancy can influence the baby's brain development. Possible effects include poor impulse control and difficulty evaluating possible consequences of different decisions. Brain scans show that kids whose mothers smoked use their brains differently than kids whose mothers didn't. The implications of this aren't entirely clear, but we do know that THC and other cannabis compounds can pass through a mother's breast milk to her child, which could compound the problem.

Our brains continue developing until we're about 25 years old, which means cannabis use in young people could also have long-term consequences. Research on teens who use pot suggests similar impairments to "executive function" - decision making, goal setting, impulse control - as in babies exposed in the womb. But there are also troubling links to altered brain anatomy, permanent reductions in IQ, and an increased risk of developing schizophrenia. In fact, some studies suggest that teens who smoke pot are six times more likely to develop the mental illness. This link might be due to genetic mutations that are risk factors for both drug-use and schizophrenia - more research is needed.

Conclusive data or not, lighting a joint seems a whole lot like playing with fire.

As for my first experience? My back spasm improved... for all of 15 minutes. Then the pain rushed back in. Making matters more irritating, I didn't feel the slightest buzz. In other words, not even remotely worth it. Your mileage may vary.

How do you feel about the legalization of marijuana?

23 Oct 2018

Claire Eamer's book wins Science Writing award!

Posted by Paula Johanson

Congratulations to our own Claire Eamer, whose book WHAT A WASTE! has just been given a Science Communication Award from the American Institute of Physics.


There are four winners chosen for these awards, and the categories are books, articles, broadcast/new media, and writing for children. Claire's fine book from Annick Press was selected in the category of writing for children. You can read the announcement on the website for American Institute of Physics at this link.

As Claire commented on Twitter:
My book, WHAT A WASTE!, has won the American Institute of Physics award for science writing for children. I am honoured, delighted, and somewhat astonished.

20 Oct 2018

School of Robots!

posted by Paula Johanson
Have you wanted to learn how to use robots for school or work? Emily Kazanowski is a student at University of British Columbia in their School of Architecture. This fall, she's taking a Robotics workshop. There's she's learning how to use a Kuka robot. This robot is a sort of mechanical arm that moves on more than one axis of motion -- 8 in all! This kind of arm has more than one elbow, and a wrist that moves in more ways than a human wrist.


Image may contain: Emily Kazanowski, smiling, standing

In this photo, Emily shows the tablet she is using to control movements of the Kuka Robotics arm. She was in the Centre for Advanced Wood Processing at the University.
"Day 3 of the Robotics Workshop at UBC! I got to operate an 8 axis capable robot. So happy!" she wrote when sharing her pictures on Facebook.
There's a video of the robotic arm in use carving a sheet of wood on her Facebook page at this link.

5 Oct 2018

A Science Trick to Try at Home

Instructions from Margriet Ruurs

You -- yes, you, right there -- can turn two solids into one liquid. It's not magic. It's science.

How can you turn a solid substance into a liquid without adding any liquid? Here’s a fun trick to try at home. All you need is a spoonful of sugar and some fresh yeast. You can buy fresh yeast at any bakery.

Instructions:
Fresh yeast. Image by Hellahulla, from
Wikimedia Commons
  • In a small bowl put a small slice of the fresh yeast.
  • Sprinkle a spoonful of sugar on top.
  • Just let it sit for a few minutes. You’ll notice the yeast turning darker.
  • After a while, take a teaspoon and stir the two solid materials. 


You’ll find that both solid ingredients have turned into a liquid all by themselves! This process is called osmosis.

White sugar is made up of solid crystals -- until the crystals
meet the moisture in the fresh yeast.
The sugar crystals dissolve because of the humidity (dampness) in the fresh yeast, forming a highly concentrated sugar solution. But the sugar concentration inside the yeast cells is low.

The liquid containing a large amount of sugar has a natural tendency to mix with the liquid that has less sugar and even out the sugar concentration. The yeast cell membranes separating the two solutions aren't strong enough to overcome that force, so the membranes break down. Then the water inside the cells bursts out. Pretty soon, all the sugar is completely dissolved in the released water.

And presto! -- Osmosis has turned your two solids into one liquid. It's a little magical, but it's science magic!

21 Sep 2018

A Frozen World Returns

By Claire Eamer

The wolf pup cleaned, preserved, and ready for display.
Yukon Government photo.
More than 50,000 years ago, when most of Canada was buried under kilometres-thick ice sheets, a wolf pup was born in one of the few places untouched by the ice -- a dry, grassy plain that extended across most of what is now the Yukon. No more than eight weeks later, the little wolf died, probably buried in a landslip and smothered while it slept in its den. The cold muck froze around it and stayed frozen, summer and winter, preserving the small body.

Just over two years ago, on July 13, 2016, gold miners on Last Chance Creek near Dawson City washed away some frozen sediment and found the little pup. It was frozen and dried but still remarkably well preserved. The miners immediately called in palaeontologist Grant Zazula and his colleagues in the Yukon government's Palaeontology Program. They were delighted with the find. To his knowledge, it's the only ice-age wolf ever found, Zazula says.

Only half of the caribou calf's body was found.
Yukon Government photo.
That was the second spectacular find of the 2016 summer. Six weeks earlier, miners on Paradise Hill -- another famous location in the historic Klondike Goldfields -- had discovered the frozen and mummified remains of a caribou calf. It wasn't as complete as the wolf pup, but nearly all of the front half of the body had survived, with skin, muscle, and hair intact.

Zazula and his colleagues knew they had something special, but they didn't realise quite how special until the results of radiocarbon dating came back. Both animals lived more than 50,000 years ago, the limit for radiocarbon dating. And the caribou calf had been found in association with a layer of volcanic ash that had settled to the ground about 80,000 years ago.

Yukon government palaeontologists Grant Zazula and Elizabeth Hall excavate
the caribou calf from the frozen muck of Paradise Hill near Dawson City, Yukon.
Yukon Government photo
Specimens that old are rare anywhere, and especially in the Yukon where the undulating landscape left few places for dead animals to lie and freeze undisturbed. There was no rush to preserve the bodies, Zazula says.

"We had them kicking around in our deep freeze for a couple of months. They were very well freeze-dried already."

The wolf pup's head before preservation, ice crystals visible.
Yukon Government photo
However, if anyone other than experts was going to see them, more work was required. Yukon Heritage applied for help from the experts at the Canadian Conservation Institute. And they got it. Today, both small bodies have been carefully thawed and preserved in a way that will make it possible to display them to the public. They are currently on display in Dawson at the Dänojà Zho Cultural Centre of the Tr’ondëk Hwëch’in First Nation, in whose traditional territory they were found. Later this fall, they will be moved to Whitehorse and a permanent display at the Yukon Beringia Interpretive Centre.

Meanwhile, scientific interest is building. Zazula is fielding calls from Pleistocene scholars around the world and brainstorming with them and his Yukon colleagues about what kind of questions the little corpses might answer. Is the wolf pup related to the wolves that live in the Yukon today, or did the Pleistocene wolf disappear to be replaced by a new population? Does the caribou calf have relatives living today? If so, which of the many caribou herds do they belong to? And that's just the beginning.

The thawing permafrost and melting ice of the world are revealing more and more clues to the past, both animal and human. That's the subject of my latest book, Out of the Ice: How Climate Change is Revealing the Past. The Yukon pup and calf are too recent to make it into the book, but it contains plenty of other fascinating evidence of lost or forgotten worlds.

14 Sep 2018

Brand New School Year, Brand New Books!

by L. E. Carmichael

Forget January, for me, September is the start of the new year - the year of learning new things! September is also Read a New Book Month, and we at Sci/Why are here to help you with that task. Discover a new favourite with our freshly-updated-for-2018 Science Book List. Here are some hot-off-the-presses choices for you and your favourite junior scientist. Captions link direct to Amazon.

Bus to the Badlands

Cats

Erupt!

Do Frogs Drink Hot Chocolate?

Hubots

Hungry for Science

Counting on Katherine

Out of the Ice

Solve This!

The Triumphant Tale of the House Sparrow

Stories in the Clouds

Wild Buildings and Bridges



31 Aug 2018

Flesh-Eating Swarms

By Adrienne Montgomerie


The buzzing starts faintly, then grows. Around and around your head, there is buzzing. Then two buzzing things, then you are surrounded by dozens of flying yellow bodies that… go on their way. Because the meat they’re looking to feed on is not you.

You might think of a sting when you think of bees, and you most definitely think of honey. But I bet you picture their fuzzy little legs heavy with yellow pollen from flowers, not a toothy grin, ripping into flesh.

A Wide World of Bees

There are almost 20 000 types of bees, and there only five types that eat meat. Common names for these flesh-eating bees include vulture bees and carrion bees. The scientific name is for this family of bees is Tragona.

They aren’t known to go out and hunt down prey. These aren’t the killer bees of folklore. These bees don’t even have a stinger!

Vulture bees typically gnaw on carrion, like vultures do. Carrion is an animal that is already dead. The only reason these bees seem to bother with living things is to keep them away from their food.

Sharing the Meat

Vulture bees usually take the bits of meat they gnaw off a dead thing back to the hive. There they spit it up (regurgitate it) as food for baby bees (larvae). This is their only source of protein. They don’t feed on flowers or collect pollen the way that other types of bees do. Their hive still produces honey though, and it is a lot like the honey we put on toast and in tea.

Some other types of bees bring meat back to the nest, but they’re using it as a building material. Those bees don’t eat the meat.

Tracking Vulture Bees

To find a vulture bee, you could try Mexico, but you’re better off going farther south to South America.



Photo of Tragona by José Reynaldo da Fonseca - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=969999