GadgetOff 2009

October 20, 2009

KenByrneby:  Ken Byrne

Ron Perkins and I had the privilege of being invited to share some of our favorite EI products at GadgetOff 2009. GadgetOff is an exhibition that includes people on the cutting edge, not just of technology, but also science, the arts, education, and the future in general.

There were so many amazing presentations that I don’t know PIC_0275which one was my favorite. Much of what we saw was just plain fun. There were two variations on an amusement park carousel, only they were powered by pulse jets. We also got to see pumpkins hurled by a trebuchet that must have been eighteen times the size of our Advanced Trebuchet Kit. But perhaps the strangest sight there was PIC_0298eight-foot diameter mechanical spider brought by a team from Vancouver. This gas-powered, hydraulically actuated monster was driven around the field like a bulldozer. It made me want to build a robot in my basement…or buy a tarantula.

There were also more serious and life-changing presentations. Segway inventor, Dean Kamen, shared with us the progress on his latest project, a prosthetic arm unlike any other. It has fully articulated human-like fingers, not a simple clasp or hook. It allows the user to pick up an egg or a grape without crushing it, and  enable the user to tell the difference between the two. All the servos, processors, sensors and everything else associated with the prosthetic arm weigh in at under three pounds!

We met dreamers, visionaries, and inventors. One group specialized in projecting large-scale artwork onto the sides of buildings using lasers. Through this, they met an artist that has been struck with amyotrophic lateral sclerosis (ALS), also known as “Lou Gehrig’s Disease.” This artist has been paralyzed below the chin for years. They developed and inexpensive eye-movement tracking system that has now given him a mean of communication, as well as the ability to make art again.

So, what did we share with these visionaries. It was a difficult choice. The other invitees showed great interest in our Mirage Illusion, especially when using it with a laser. They all mir100knew that the image of the pig floating above the Mirage was an illusion, so were amazed that you could still hit it with the laser beam.

Ron also demonstrated his BB Board, a devise of his own design. With it you can easily explain how molecules reorganize when hs12heat-treated, show movement of geological formations, and visualizing the motion of solid liquids and gas particles.

Everyone also loved the sneak preview of our new device for transmitting sound using a common laser pointer. This device will be available soon. Look for the announcement in our newsletter.

As always, one of the favorites was the FunFlyStick. This is our mini Van de Graaff van200generator with its floating toys that seem to defy gravity.

We truly appreciate the opportunity to attend GadgetOff and are grateful to Michael and Dan for extending yet another invitation to us this year!

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Posted by Tami O'Connor

Goldenrod Paper

October 1, 2009

ronby: Ron Perkins

Color changing goldenrod paper has been exciting students of all ages for decades to the wonders chemistry! Imagine the enthusiasm of the first student or teacher who spilled a few drops of ammonia on a piece of yellow paper and observed it turn bright red! One can only image them exclaiming: “Super, Wow, Neat!!!”

Place the paper in a solution of household baking soda and the paper turns red; immerse it in vinegar and the red turns back to yellow! This goldenrod paper is colored with a dye that is an acid/base indicator: red in base and yellow in acid. The paper is similar to litmus paper that is blue in base and red in acid.

Even though color changing, goldenrod paper is no longer being manufactured, Educational Innovations, Inc. still has a supply and the paper is being sold in 100 sheet packages, (#SM-925). This special paper was being manufactured until Junesm925 of 2008. At that time the process was changed to use a different dye that is more cost effective and better for the environment. Currently, paper of the same color, Galaxy Gold, is being offered by retail office supply stores, however, this paper uses a different dye and is not color changing.

Simple Activities With Goldenrod Paper

1. Write a “secret” message on the paper with paraffin or candle wax. The invisible message can be seen by spraying or wiping the paper with a weak basic solution e.g. ammonia (NH3 (aq)) or baking soda (NaHCO3). If you use ammonia solution, the message will disappear when the ammonia evaporates. If you use a baking soda solution, the message will remain.

2. Write a message on the paper using a cotton swab dipped into household ammonia. As the ammonia evaporates, the red message disappears.

3. Repeat Activity #2 using a cotton swab dipped into a solution of baking or washing soda. The message can be erased using vinegar (HAc) as “Yellowout .”

4. Use goldenrod paper to classify household products as acidic or basic. Solutions that turn yellow paper red are bases; solutions that turn red paper yellow are acids; and solutions that do not turn the color of either paper are considered “neutral.”

5. Tape a piece of yellow goldenrod paper to the board. Dip your hand into a shallow container of baking or washing soda and water. Then, when you press your hand against the paper, you will leave a “bloody” hand-print. Especially useful at Halloween. Compliments of Bob Becker 1985, Greenwich High School

6. Sponge the surface of a piece of goldenrod paper with a baking soda or washing soda solution and allow the wet, bright red paper to dry. Then, tape the paper to the board and press a hand that has been dipped into vinegar against the paper. The yellow hand-print will be the reverse or the “negative” of the result in activity #5. Complements of Carl Ahlers 2008, Australia

More Advanced Activities with Goldenrod Paper

7. Sponge a solution of baking soda or washing soda on a piece of goldenrod paper. Observe that the red color becomes gradually darker. Explain? Carl Ahlers has written: “Drying shifts the equilibrium in reaction 1 to the right as the H2CO3 is reduced due to the evolving of CO2 gas (reaction 2) (Le Chatelier). Subsequently more of the red Gol forms on drying. HGol (yellow) + HCO31- <—> Gol1- (red) + H2CO3 (aq) Reaction 1 H2CO3 (aq) <—> CO2 + H2O Reaction 2

8. Determine the equilibrium constant, the Ka, for this acid/base indicator. One way is to prepare a set of different pH solutions using a method of serial serial dilution on a spot plate or in small test tubes. Then, test to see at what pH the color change seems to occur for this indicator paper.

9. Make color-changing paper similar to goldenrod paper using household tumeric powder. Although tumeric is insoluble in water, in a workshop at Sacred Heart University, ca 1987, we discovered it was soluble in either ammonia or ethyl alcohol. White paper dipped in a solution of ammonia with dissolved tumeric will be dyed red which turns to yellow as the paper dries; dipped in a solution of tumeric and alcohol, the paper will remain yellow as it dries. When dry, test and observe how similar and how different the paper is from the color-changing goldenrod. Note: although this paper seems to react similar to color-changing goldenrod, the color fades much faster.

10. Prepare acid/base color changing paper using natural indicators: rose petals, purple cabbage, etc. Then determine the pKa of the paper.

2 Comments | Chemistry, College Level, Elementary Level, Experiments, High School Level, Middle School Level | Tagged: , , , , , | Permalink
Posted by Tami O'Connor

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