Making Geometric Images with a Smart Phone and a Teleidoscope

In 1817, Scottish inventor and optical scientist Sir David Brewster invented a tube with opposing mirrors running through it and beads of colored glass in one end. He called it the “kaleidoscope,” a word whose Greek roots mean “beautiful shape viewer,” which most of us have peered through and hooted in awe at around kindergarten age. It’s a simple design that capitalizes on a trick of light to incredible effects. Three mirrors arranged in a triangle reflect the light entering one end of the scope down the tube and across to each other. By the time it reaches your eye, it has reflected so many times it creates the effect of a precise geometric pattern that infinitely changes.

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Sir David Brewster.

Back in the nineteenth century, when optics were a new thing, this wasn’t just awe-inspiring for children; even adults were impressed. But Sir Brewster neglected to patent his kaleidoscope, and others copied the new technology and began manufacturing it as a child’s toy, likely costing him millions in potential income and in reputation. Good thing he had other inventions to lean on.

Sir Brewster is responsible for inventing the first portable 3D viewing device, which he called the “lenticular stereoscope.” He built the first binocular camera, the lighthouse illuminator, the polyzonal lens, and two types of polarimeters, a scientific instrument used to measure the angle of rotation caused by passing light through an optically active substance. This last device is used in the chemical industry to test the properties of new substances.

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John Lyon Burnside, III.

In 1972, the kaleidoscope’s potential was pushed a step further. John Lyon Burnside, III and Harry Hay patented a version of the geometry-creating tube that scrapped the bits of colored glass and replaced it with a spherical lens, allowing the viewer to point the viewing tube at any object in nature to see it reduplicated across the mirrors in the same way. They dubbed it the “teleidoscope.”

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At the Houston Museum of Natural Science, we sell both kaleidoscopes and teleidoscopes in the Museum Store. As a lover of photography, nature and geometric patterns, I experimented with this teleidoscope and my iPhone and captured some amazing images in the Cockrell Butterfly Center, the Cullen Hall of Gems and Minerals, and other locations around the museum. Some things work better than others, but for the most part, everything looks incredible through one of these bad boys.

Here’s how you do it, in photo steps. (You can get this awesome notebook at the Museum Store, as well.)

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Grab a cool thing to take a photo of (or just go outside), and bring your teleidoscope and your smart phone or digital camera.

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Hold the viewing end of the teleidoscope against the lens of your smart phone or digital camera. Make sure it’s tight and that there’s no light leaking around the edges. It takes some practice, but you’ll learn quickly.

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Align your shot and snap it when you see a pattern you like. The edges will appear darker than the center. This is yet another property of light as it bounces around inside the scope.

And here are some of the images I made, cropped down to a square, eliminating the dark edges. What do you think?

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Roof of the Cockrell Butterfly Center.

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Mandrake the Corpse Flower.

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Andelusite.

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Green fluorite and white barite.

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Pink phalaenopsis orchid.

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Orchid mantis.

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Owl butterfly.

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Rice paper butterfly.

MirrorSandstoneConcretion

Sandstone concretion.

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Spondylus shell.

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Orchid.

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Giant squid model.

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Orchid.

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Zebra longwing butterfly.

Everything looks better through a teleidoscope! So buy one or make your own, and post your images on our social media. Your images look even better with Instagram filters! Don’t forget to tag us with #hmns and @hmns. We’d love to see what you come up with.

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Earlier photo through Instagram’s Juno filter, with a few other adjustments I’ll keep secret. 😉

Educator How-To: The eyes have it in this DIY optical illusion

Your eyes are amazing sensory organs. They help you understand shape, color and form, judge distance and alert you to potential dangers. What you perceive as “seeing” is actually the result of a complex series of events that occur between your brain, your eyes and the world around you.

Light reflected from an object passes through the cornea of the eye and moves through the lens, which focuses it. The light then reaches the retina at the very back of the eye, where it meets a thin layer of color-sensitive cells called the rods and cones. Information from the retina travels from the eye to the brain via the optic nerve.

Because eyes see from slightly different positions, the brain must mix the two images it receives to get a complete picture. The light also crisscrosses while going through the cornea so the retina “sees” the image upside down. The brain then “reads” the image and turns it right-side up.

The rods and cones are what you call photoreceptors. When they are overworked, they lose sensitivity. Normally the small movements of your eyes that you make unconsciously, or regular blinking, will keep these photoreceptors sharp and happy. If you are looking at a large enough image, where your eyes can’t rest, or if you purposely hold your eyes still, you will tire out your poor rods and cones and they will adapt to this overstimulation by no longer responding. When you move your eyes to a blank space, your worn out photoreceptors create an “afterimage”.  An afterimage is where your eyes produce a ghost image, like when you stare at something a little too bright and you see dark spots in your field of vision. In an afterimage, light portions of the original image are replaced by dark portions and dark portions are replaced by light portions.

Try this out for yourself by doing the following activity. 

You will create the Texas state flag in some unusual colors. After you stare at this incorrectly colored flag and have worn out your photoreceptors, looking at a blank wall will create a ghost image of the Texas state flag in red, white and blue!

Activity:  Negative Afterimage

Materials:
Scissors
Glue
Paper
Green construction paper
Black construction paper
Yellow construction paper 

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Procedure:

1. Cut your green and yellow papers in thirds, width-wise.

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2. Cut a star out of the middle of your yellow piece.

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3. Glue the yellow piece to one end of the black piece.
4. Turn the black paper so that your yellow piece is placed on the left.

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5. Glue the green piece to the bottom of the black piece.
6. Trim off any extra green.

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Now stare at the flag for a minute or so. Try not to have much in your peripheral vision so that you can concentrate on the flag.

Look away from the flag at a neutral colored wall or piece of paper.  You should be able to see the flag in red, white and blue!

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Have a school group and want to know more about how your eyes work?  Sign up for an Eyeball Dissection with our Labs on Demand.  These labs make a great addition to a field trip, but are also available to come to your school.

Interested in knowing more about how your body works?  Visit Body Carnival, a carnival-themed interactive exhibit that explores the connections between perception and the laws of physics in the human body, at HMNS Sugar Land. Enjoy learning about the human body while investigating force, pressure, light, and color. Crawl through a giant artery to see and hear the effects of restricted blood flow, test your balance in the 10-foot Dizzy Tunnel or don a pair of vision-distorting goggles and discover how sight affects your ability to walk straight. There’s a lot to explore!

 

I can’t find my reading glasses, but I’ll manage.

You’ve probably noticed the magnifying effect of a glass of water or any other clear beverage (the black text to the right of the glass is the same size as the black text behind the glass):

And you probably have some idea that the magnification has to do with the curved shape of the glass and the water it contains: The water in the glass bends light so it appears to us to be coming from an object that is bigger or closer than it really is.

To explore this more, try making differently sized water drops on top of a sheet of waxed paper (the waxed paper helps the water ‘bead up,’ which improves the effect):

You’re aiming for a large drop about 2 centimeters or 1 inch across, and medium and small drops that are, well, smaller.  If you don’t have an eyedropper to help you, you can either pour extremely carefully or dip a pencil or spoon in water and let the water drip off of it.

Look at a page with words through the drops (don’t use your first editions of The Old Man and the Sea or Einstein’s General Theory of Relativity, because the water will eventually seep through the waxed paper and make you very, very sad).  Do you see any differences between the larger and smaller drops?

This looks much clearer if you try it yourself, so go do it! 

You may be thinking “My large drops (possibly puddles) don’t seem to change anything; why do the small drops work so much better?”  To explain this, try looking at your drops from the side (your eyes should be level with the surface of your table:

The shapes are different: The largest drop looks almost flat across the top, while the smallest drop makes a very tidy little dome shape.  Another way to say this is that the smallest drop’s surface is more sharply curved, or is more convex than the larger drops (convex surfaces bulge out, concave surfaces “cave in.” And it turns out that the less convex the surface of the drop, the less it magnifies.  If you want a more in depth explanation with diagrams, check out this site.

Convex and concave lenses are used in all kinds of cool equipment. For more information on lenses and the anatomy of your eyeballs, check out The Anatomy of the Eye.