 At left in the back is a fresh spinach leaf that has been treated with trehalose, frozen and defrosted.. The droopy one has been frozen and defrosted without trehalose. It's what is giving us hope that we may soon be able to defrost a salad. When it comes to preserving a fresh taste in food to be eaten at some later time, nothing beats freezing it. That was the discovery made by Clarence Birdseye in 1924. He had been working in northern Canada and noticed that fish caught by the native Canadian Inuits froze almost instantly in the frigid winter air. It was just as delicious when cooked and eaten months later as it was on the day it was fresh. Birdseye figured that if food was frozen quickly at very cold temperatures, large ice crystals couldn’t form to damage the food and make it mushy. His flash-freezing process made him very rich. The problem isn’t so much the freezing of food as what happens when it’s defrosted. See for yourself. Stick a stalk of celery in your freezer. The next day defrost it. Want to eat it? Compare it to a fresh unfrozen stalk. The perky structure of fresh celery is destroyed by ice. Water has the very unusual property of expanding and taking up more space when it changes into ice than when in a liquid state. That’s why ice cubes float and frozen unopened soda cans bulge. Expanding ice crystals destroy the cell walls of plants. Quickly freezing fresh food keeps the ice crystals smaller than slower freezing, but they are still large enough to destroy the cell walls of delicate vegetables like spinach or lettuce. But if you defrost frozen spinach from the supermarket it is beyond limp. So a salad you can defrost and serve as if it were fresh has seemed like an impossible dream. Federico Gomez, a Swedish scientist, is working to change this. Like Birdseye he took a close look at nature, specifically at plants that stay alive in very cold climates. He discovered that they contain a sugar called trehalose (tree-HAL-ose) that works like a natural antifreeze. Could he find a way to get trehalose into spinach leaves? If so, would the trehalose protect the structure of the spinach and keep it crisp after defrosting? This picture shows the results. The leaf on the left was treated with trehalose. The one on the right was untreated. He froze and defrosted both. The treated leaf is as crisp as if it had never been frozen! Just because there is success in a lab doesn’t mean a defrosted salad will show up on your dinner plate any time soon. But these results are enough to keep the research going. Move over Clarence Birdseye!
 Cobb has revised her classic book, Science Experiments You Can Eat. While doing her research, she came across this work of Frederico Gomez. She bought trehalose on line and soaked some slices of parsnip and zucchini in a trehalose solution, hoping that the sugar would be absorbed by the plant cells. But when she froze them and defrosted them, it didn't work. Dr. Gomez got the sugar inside the plant cells by removing some water from between the cells in a vacuum chamber, soaking the leaves in a trehalose solution (which moved the sugar into the spaces outside the cells) and then exposing the leaves with a mild electric shock to get the sugar through the cell walls. Vicki didn't have the equipment to do all this but she tried anyway. The book was published in 2016. Vicki Cobb is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more. MLA 8 Citation Cobb, Vicki. "Why You Can't Defrost a Salad...Yet." Nonfiction Minute, iNK Think Tank, 11 01 2018, www.nonfictionminute.org/the-nonfiction-minute/ Why-You-Can't-Defrost-a-Salad-Yet. 
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Think you might like to be a helicopter pilot? If so, here’s what the U.S. Flight Aptitude Selection Test for helicopter pilots says: “Helicopter pilots must pass some of the most demanding physical tests of any job in the military. To be accepted for pilot training, applicants must have excellent vision and be in top physical condition. They must have very good eye-hand-foot coordination and have quick reflexes.” A sense of balance is also extremely important because sometimes instruments alone are not enough to keep a helicopter oriented properly in the air. Pilots may have to make very subtle corrections. So here’s a test for balance. Be forewarned. Not many people can do this, maybe one in twenty. 1. Stand at attention. 2. Make two fists and extend your arms straight down by your sides. Point your index fingers to the ground. 3. Close your eyes. 4. Bend one leg back at the knee so that your lower leg is parallel to the floor and you are standing on one foot. Don’t let your foot droop. You must maintain your knee at a right angle. 5. Keep your eyes closed and hold this position for ninety seconds. 6. Try not to shake. I learned about this from a Scotsman who told me about this test to qualify for the British Royal Air Force. He couldn't pass it, nor could I. In fact, no one I knew could rise to the helicopter pilot challenge except a Navy pilot in my family. He held the position perfectly for two minutes. Solid like a rock. No problem. It’s clear that when it comes to certain skills not everyone is equal. Some people are not even close. So very few people are in the running to become helicopter pilots. You're probably not one of them but this may change with training.  This young man is an athlete who actually wants to be a helicopter pilot. He passed the test and is holding the correct position. Not sure if the bare feet helped. Photo credit: Alexandra Siy  Vicki Cobb is a former science teacher with a M.A. in secondary school science. She is also the founder and president of iNK Think Tank, the group that is producing The Nonfiction Minute. Thanks, Vicki! Check out How Could We Harness a Hurricane?. To find out more about this book and other books that Vicki has written, click here. Vicki Cobb is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more. MLA 8 CItation Cobb, Vicki. "Take the Helicopter Pilot Challenge." Nonfiction Minute, iNK Think Tank, 4 Jan. 2018, www.nonfictionminute.org/ Take-the-Helicopter-Pilot-Challenge.  
 A land surveyor sends a heliograph to his partner more than 100 years ago. He must have been fluent in Morse Code How do you know it’s the holiday season? There are lights everywhere sending that message. But that’s not the only kind of message light can send. A little more than 100 years ago when a telegraph began to become popular, people sent wireless messages called heliographs. They were made of flashes of light in Morse code (the same pattern of short and long as used in telegraphs) by reflecting the sun’s rays with a mirror. When the mirror was at a particular angle to the sun, it reflected a flash of bright light to observer miles away.  Note where the red light from the bulb emerges on the opposite side. Some internally reflected light is emerging from a ridge in the glass. Photo by Alexandra Siy Maybe there’s another way to send light. Put a holiday light on one rim of a heavy glass measuring cup or dish. See where the light emerges on the rim on the opposite side. Move the light back and forth and watch what happens on the other side. The light travels down the side, and bends to go across the bottom and up the other side, but if you look at the cup sideways you can’t see the beam. Light stays inside the glass as it travels from rim to rim. Could we make something like a wire from glass that can transmit light? Absolutely! An optical fiber is a flexible, transparent fiber made of glass or plastic that acts as a wire for light. Imagine a beam of light entering a fiber at exactly the right angle to bounce off the inside wall of the fiber where it meets the air. It is then reflected at exactly the same angle to bounce off the opposite wall making a zig-zag path until it reaches the end of the fiber. This internally reflected light stays inside the glass fiber as it travels at the speed of light. HUGE quantities of all kinds of information—words, pictures, music, and videos—can now be sent through optical fibers, much more than through wires. A modern network with copper wiring can handle about 3,000 telephone calls at the same time, while a similar system using fiber optics can carry more than 30,000! So when you hit “send,” know that your holiday message is a blinking beam of light, bouncing off the inside walls of a glass fiber on its speedy journey to friends and family. How ‘bout that!  Fiber optics can be made into holiday decorations. Note the bright light emerging from the ends of the fibers.  Want to know more about optics? Have a look at Vicki Cobb's book Light Action! She co-authored it with her son, Josh, who is an optical engineer and her other son, Theo, drew the pictures. It's full of experiments that let you use optics to: -Bend light around corners - Stop time with a pair of sunglasses - Capture light on a silver tray - Magnify pictures with an ice cube - Pour light into your palm - Project a big-screen image from your small TV - Fool a doorbell with a bike reflector! For more information, go here. Vicki is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more. MLA 8 Citation Cobb, Vicki. "What Can You Learn from a Holiday Light and a Glass Cup?" Nonfiction Minute, iNK Think Tank, 14 Dec. 2017, www.nonfictionminute.org/ What-Can-You-Learn-from-a-Holiday-Light-and-a-Glass-Cup. 
Polar bears are built to withstand some of the coldest temperatures on the planet. Their brown and black bear cousins avoid the winter cold by digging dens and sleeping. But, except for pregnant females, polar bears spend the arctic winter outside where temperatures could be -40° F (which equals-40 °C) and windy. That’s too cold for humans. You could go outside, but only for only a few minutes with every part of your body completely covered. And if you didn’t wear goggles, your eyelashes would freeze and break off if you touched them. Polar bears are warm-blooded like us with a body temperature of about 98°F/37°C. But they are invisible to night-vision goggles that pick up the infrared rays that warm-blooded creatures, including humans, give off. Why? Nature has given polar bears enough insulation to prevent body heat from escaping. They are toasty warm and comfortable in the frigid arctic. Their heat insulation is in several layers. Under their skin, there is a 4-inch (21.5 cm) layer of fat. Next to the skin is a dense layer of woolly fur that also keeps heat in. The fur you see is a thick layer of long, colorless guard hairs that shed water quickly after a swim. They are stiff and transparent and hollow. In the arctic sunlight, the hairs act like mirrors and reflect white light, which acts as camouflage against the snow so the bears are not seen by their prey. Polar bear skin is actually black, so that it can absorb the invisible warm infrared rays of the sun and the bear’s own body heat, both of which are reflected back by the guard hairs. Most warm-blooded animals raise their body temperatures through exercise. Polar bears hunt seals, which they don’t often chase. They prefer to sit at the edge of an ice floe and wait for dinner to arrive. At best, they’ll lumber after a seal at four and a half miles (7.25 km) an hour, raising their body heat to 100°F (38°C). When that happens, they go for a swim to cool off. Cold won’t kill off the polar bears, but global warming can. As polar ice disappears, so does the hunting ground for seals. Not so cool!  ​The polar bear is the largest land carnivore. Its long non-retractable claws help it get a grip on the icy surface it prowls for prey. Wikimedia Commons  Close up, the polar bear guard hairs are transparent. This allows the infra-red light (heat) from the sun to pass through them to be absorbed by the black skin under the hairs. The hairs also act like mirrors , reflecting back to the skin any infra-red radiation escaping from the bears body so it can be reabsorbed. Thus, the insulation is just about perfect with no infra-red radiation escaping. The hairs are also coated with oil so they drain quickly after a swim.  The polar bears’ white appearance serves as ideal camouflage in a snow-covered environment. Art by Barbara Lavelle from This Place is Cold by Vicki Cobb.  Vicki Cobb's This Place Is Cold shows how the latitude of Alaska affects the lives of the plants, animals and people who live there. It is gloriously illustrated by Barbara Lavallee, a long-time Alaskan resident and artist. Vicki is a member of Authors on Call—she can visit your classroom with interactive videoconferencing: Read more about her here. MLA 8 Citation Cobb, Vicki. "The Way Polar Bears Keep Warm Is Cool." Nonfiction Minute, iNK Think Tank, 29 Nov. 2017, www.nonfictionminute.org/The-Way-Polar-Bears-Keep-Warm-Is-Cool.  
Are your two nostrils exactly the same size? Don’t struggle to find out by looking in a small mirror. Put your nose right above the mirror and breathe down on it. You will see two circles of moisture as the warm moist air from your nose condenses into water when it hits the cool mirror surface. One circle will be a LOT larger than the other. You might conclude that yes, one nostril is bigger than the other; that you will have to live with being lopsided. But wait! I mean wait an hour or so and do it again. Surprise! This time the small nostril is now the BIG one! The larger nostril is dominant and takes in more of the air. You can do scientific study of your nose and see just how long each nostril dominates. Perhaps if you check often enough, you’ll discover a time when the two circles will be about the same size. This will be the moment of the changing of the nostrils. Of course, you have to do this study when you don’t have a stuffy nose. What’s behind this? It seems that your nostrils are on an automatic timer from your brain so that they take turns being dominant. It’s very interesting. But I’m not sure if it is important. Not many people know about this. But your dentist might. A dentist is always looking at peoples’ nostrils. See if your dentist knows about this. He or she might even know why this happens. This just might be a medical mystery worth investigating. And you might be just the one to do it.
 Vicki Cobb ‘s “Discover Your Senses” series of books are available through the iTunes store. She begins by asking: “Know how to stop smelling? Hold your nose.” Also, check your library for copies. I mean wait an hour or so and do it again. Vicki is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more. MLA 8 Citation Cobb, Vicki. "The Mystery of the Alternating Nostrils." Nonfiction Minute, iNK Think Tank, 21 Nov. 2017, www.nonfictionminute.org/the-mystery-of-the-alternating-nostrils.  |
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For Vicki Cobb's BLOG (nonfiction book reviews, info on education, more), click here: Vicki's Blog *NEWSFLASH *
The NCSS-CBC Notable Social Studies Committee is pleased to inform you that 30 People Who Changed the World has been selected for Notable Social Studies Trade Books for Young People 2018, a cooperative project of the National Council for the Social Studies (NCSS) & the Children’s Book Council Categories
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