Category: Light

What Can You Learn from a Holiday Light and a Glass Cup?

12/20/2021

Vicki Cobb
The Master Chef of Kids’ Hands-on science

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.

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Isaac Newton's Wonder Years

4/2/2021

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Kerrie Logan Hollihan
Teaching the Power of Wonder

   In spring 1665 a college student named Isaac Newton studied natural philosophy, what we call “science.” Back then, a good student could learn everything to know about the natural world. But plague, the Black Death, came to England. Cambridge University closed. Isaac went home to Woolsthorpe.

            For two years Isaac thought about his studies during four years at university. He’d always been thoughtful—not the best at games, making friends, or minding sheep. But everybody knew Isaac Newton liked to think. Folks told time by the sundial he’d drawn on a wall.

            Home at Woolsthorpe, Isaac’s learning about science and math bubbled up in his head like yeast rising in a loaf of bread.

            So... Newton unplugged. His mind roamed like that of an artist or composer. He was driven by the need to create—not paintings or symphonies, but questions.

            “Why do things always fall down?”

            “Why does the earth move around the sun?

            “Why doesn’t the moon fall onto the earth?”

            “Does everything ‘up there” work like things work ‘down here?’”

            Isaac Newton answered his questions with three science rules, Newton’s Laws of Motion.

            At Woolsthorpe, Newton grappled with the concept of moving objects. He worked out the math to find the area under curves. He called this math fluxions. Today we call this calculus, useful for launching rockets or tracking TV signals.

            Once back at Cambridge, Newton said nothing until he read someone else’s paper on fluxions. Newton published a better paper. Soon he was Cambridge’s top math professor.

            Isaac Newton wondered another twenty years. He played with prisms in a dark room and theorized that white light comprises the visible spectrum of red, orange, yellow, green, blue, indigo, and violet. He practiced alchemy and chemistry, looking for the legendary philosopher’s stone to turn base metals to gold. In 1687, Newton published our most important science book, the Principia.

            In the Principia, Newton showed how laws of gravity and motion work the same at great distances—far off in space, or in your classroom. We accept these ideas, but in 1687 many still had medieval beliefs that sun, moon, planets, and stars all traveled in their own crystal spheres.

            Yes, Newton wondered about A LOT:

Gravity
Forces
Mass
Inertia
Math
Motion
Light
God
???

Whatever interests you, I hope you’ll think about it—a lot! Like Isaac Newton, take time to WONDER!

Sir Isaac Newton was an English mathematician, astronomer, theologian, author and physicist who is widely recognized as one of the most influential scientists of all time and a key figure in the scientific revolution. Based on a portrait by Godfrey Kneller, 1702, via Wikimedia Commons

Sir Isaac Newton's own first edition copy of his Philosophiae Naturalis Principia Mathematica with his handwritten corrections for the twentieth edition. Photograph Andrew Dunn via Wikimedia Commons

Trinity College, the part of the University of Cambridge where Newton worked and lived. Library of Congress

This statue of the young Isaac Newton stands at the Oxford University Museum of Natural History. Look carefully around his feet for a hint on what he is wondering about. If you can’t figure it out, then read about Newton and gravity.
Wikimedia Commons

Featuring 21 hands-on projects that explore the scientific concepts Isaac Newton developed, Kerrie Logan Hollihan's Isaac Newton and Physics for Kids paints a rich portrait of the brilliant and complex man and provides readers with a hands-on understanding of astronomy, physics, and mathematics. A time line, excerpts from Newton's own writings, online resources, and a reading list enhance this unique activity book.

MLA 8 Citation
Hollihan, Kerrie Logan. "Isaac Newton's Wonder Years." Nonfiction Minute, iNK
Think Tank, 21 Feb. 2018, www.nonfictionminute.org/the-nonfiction-minute/
isaac-newtons-wonder years.

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What Can You Learn from a Holiday Light and a Glass Cup?

Isaac Newton's Wonder Years

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