Field Trip Explainers

Reflections on life at Exploratorium

Tag: exhibit

My New Favorite Exhibit

by lianna

Lately I have been spending an inordinate amount of time with the Tiling Table.  Many a roam mid have turned into “sit-and-make-a-pretty-pattern” and are over before I know it.  It’s funny, because although I’m in my third year of working at the Explo, I’ve spent very little time with this exhibit up until now.  Pattern blocks used to be one of my favorite activities in elementary school, so why has it taken me so long to rekindle my love for these little blocks?


When I was younger, I would always start with the same pattern: yellow hexagon in the middle with six red trapezoids to make a flower, with green triangles for a stem and leaves.  And don’t get me started on how frustrating it was to my six year old brain why those two of those darn green triangles wouldn’t make a square (if only I had known about right angles back then!).  Now, I’m super interested in making patterns that tesselate, especially ones that use the diamonds.  I like to imagine what a whole floor of these patterns would look like as I create them.


Here are a couple of my recent creations:


It started like this…


And 30 minutes later…


Honestly, I’m surprised it lasted as long as it did.


This one was an accidental optical illusion.  My original goal was to make a tessellating shape that had a square as the starting place and included diamonds.




Anybody else addicted to a particular exhibit right now?

How many exhibits can you fit in one four minute music video?

by lianna

In the jungle that YouTube can sometimes be, I stumbled across this video a few months ago and found it fascinating.  Since then I have returned to it several times, not because the song is anything special, but because the video itself is so fun to watch.

It’s fun to see the exhibits that are so familiar to us presented in such a different way.  And that got me thinking, exactly how many exhibits are in that video?  At first I thought that would be easy to figure out — watch and count.  But how do you decide which illusions count?  Ones that are related to exhibits?  Ones that are identical to exhibits?  What about the ones that used to be on the floor and aren’t anymore?  And how many times did the team in white bounce the ball? (just kidding…)

So I propose a challenge to all you explainers out there.  Watch it and count up how many exhibits you see.  Then we can compare answers!  I’d love to hear your perspective on it.

Why Tea Leaves Settle in the Center of a Mug

by Aiona

einstein.jpgAs part of explainer training we completed an example worksheet with a very simple question on it concerning the spinning tea leaf exhibit. “Why do tea leaves settle in the center of the cup?” Several of us pondered this for several minutes and came up with some adequate sounding answers, but I sensed I still hadn’t grasped what was really going on. After an entire week of quizzing physics students, searching the internet, and staring obsessively and abysmally into the bottom of tea cups, I finally found a satisfactory explanation, which, like any good know-it-all, I am posting here for your reading pleasure. By the way, this problem is commonly referred to as the “tea leaf paradox,” and it remained unsolved for decades until Einstein lent his genius to resolving the problem. It may be a bit unfair to be grading 5th graders on that.

“When a person stirs a liquid in a cup, they create a primary flow of the liquid that involves a constant rotation around the center of the cup. Almost like the rotation of a solid body. In order to go around in circles, which involves acceleration toward the center of rotation, the liquid requires a centripetal force on each unit mass. A pressure gradient directed outward through the rotating fluid, and terminating at the solid wall of the cup, supplies this force; and a person can see the effect of this pressure gradient by noticing that the rotating fluid free-surface is shaped like a parabola with the highest fluid surface out near the cup rim. This state of affairs is not in equilibrium, unfortunately, and there develops a secondary flow of liquid which is the real focus of our attention in explaining the behavior of the tea leaves.

This secondary flow of liquid depends on the free surface of liquid in the cup, and friction (viscosity) of the liquid at the cup surface. It occurs in the following way. Viscosity prevents any relative motion between the liquid and the cup at the point of contact. In effect the fluid is “stuck” to the solid surface of the cup, and must come to rest there. A fluid dynamicist would say that there is fluid in a thin “boundary layer” near the solid cup surface in which fluid behaves differently than it does in the bulk of the primary flow. Fluid is also at rest along a vertical line at the exact center of rotation near the center of the cup. But there is a greater height of fluid near the cup wall than there is at cup center, and what results is a pressure gradient that sends fluid along the floor of the cup inward. This disturbs the basic solid rotation of liquid throughout the cup.

Thus a secondary flow now develops that consists of fluid that flows inward at the bottom of the cup, rises at the center of the cup (center of rotation actually), flows outward near the surface, and finally downward along the walls. This secondary flow will sweep loose material, like tea leaves, toward the center of the bottom of the cup. A fluid dynamicist would say that there is a “point of stagnation” on the bottom of the cup near the center, and once materials reach this stagnation point they remain there. Eventually this secondary flow will de-spin the liquid, flatten the surface, and bring everything to a state of rest.”

copied from Kevin Kilty writing for The Citizen Scientist;helical flow this explanation can be found at:

Comparing Yellows

by ryan

It’s the start of a school year which means that we have new explainers, new school groups and new Paul D! Well, actually its the same Paul D., but we get to learn new science facts and experience new exhibits.

Today Paul talked about this exhibit called ‘Comparing Yellows’. It doesn’t come across so well in the photo, but the basic idea is that the center dot is a light emitting diode showing ‘pure yellow light’, while the outside ring has a gradient of ‘green and red light’. The crazy thing that Paul told us was that the colors of light is something entirely created by human perception. Each person has a slightly different combination of ‘cones’ in the color receiving cells in the retina. Most people in our group saw the center dot as the same as the dot at 1 or 2 o’clock but Katie and Chris perceived the middle dot as similar to the greenish dot at 7 o’clock. That’s because they have forms of color blindness which occurs in 1/10th of men and 1/100th of women.

This helped us realize that each visitor to the ExplOratorium may experience the exhibit in an entirely different way. There is no ‘right or wrong’ way to interact with an exhibit, and that’s what makes this place excellently cool.

Make and Break Exhibits

by ryan

 We’ve debuted some cool temporary exhibits at the ExplOratorium over the past few months. The kids at our summer camp made the first exhibit which hangs from the circle of lights in the middle of the museum. For one of our activities, the campers dissected computer keyboards and made flying “cy-birds” from the plastic sheets that lie under the keys. The project allows the kids to create an piece of art that will stay on the floor for the next month or so. I think that the idea of having an exhibit like this demonstrates the spirit of the ExplOratorium as a museum without pretentions about who can make art, do science or contribute to the exhibit space.

The second temporary exhibit going on at the ExplOratorium is a totally amazing sculpture created by the visiting artist Aeneas Wilder. His piece on display at the current moment is titled Untitled No. 133 and can be found in the art space in the back corner of the museum surrounded by the mind section. One amazing thing about the exhibit is that the entire thing is constructed without any glue, nails, or material which holds the pieces together. It’s sort of like a giant Jenga game, although for some reason it probably wouldn’t stay standing if I tried to remove a plank even though I have super steady hands. So the other crazy thing about the exhibit is that the artist kicked down two previous versions of the artwork before settling on the current design. Earlier in the summer, I saw him building a twisting tower which he later knocked down with a mighty boot, creating a loud noise that apparently echoed throughout the entire museum. Watch the video on his website here if you don’t believe me! If anyone wants to check out the demise of the current installation live, I believe that the plans are to knock it down on Labor Day at 4PM.

Something about the piece reminded me of the Marble Machines that the PIE institute has been working with over the past year. Like the marble machines, Wilder’s works is made of simple materials and by nature temporary. I remember that after working on my peg board for only a few hours, I was extremely reluctant to take the pieces apart. I can only imagine what it would be like to destroy something that you spent so much time, planning, and precise placing of wooden boards. Although the spectacle of the crash might be pretty damn satisfying.

The making of a pyro.

by akikoakiko

These days, I’ve been spending a lot of time with Catch a Falling Spark.  I was with a kid the other day, and we were taking turns cranking the handle at warp speed and smushing the steel down to make the sparks triple in volume.  This kid was cranking so hard, he was yelling his manliest, “HAAAAAAAAAAAAAH!” yell that his 9-year old lungs could project as he cranked with both arms.

After we thoroughly exhausted ourselves, he asked me if we could start a fire with this thing.  Although I knew the answer was no, I said, “Do you have any paper?”  He got so excited, he gave me his worksheet, and wore out our arms again as we tried to Catch a Spark onto his Pathways worksheet on Magnetism.

There’s something about the possibility of a fire that makes this exhibit exciting and potentially badass.  Fire is fascinating.  And can I just say, my arms are looking way toned!

How Does It Feel To Talk To A Fish?

by ryan

Ok, I’ll admit it. I was wrong. I used to doubt the ehibit “Talk to a Fish”. I thought it was super-lame- one of the lamest exhibits on the floor. I mean, come on…it’s a flourescent pink phone in a tank with a wierd blue fish. When you pick up the phone it makes muffled farting noises. What’s there to like about it?

Well, today I got the answer – A lot!

It all started about one o’clock when Dawn and I were roaming the mid and kept seeing the same group of kids huddled excitedly around Mr. Fish’s tank.

They were about third graders and were having the funniest conversation with the fish. They found out all about it including it’s birthday (May 18th) and it’s age (2 yrs old). They had some great questions for Mr. Fish and some equally awsome responses. For example…

Kid #1 – Do you know 5+5?
(A beat)
Kid #1 – Oh almost, actually it’s 10. (then to us) He said 9.


Kid #2 – Do you know your ABC’s
Kid #2 – No, actually it’s A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z…not F-I-S-H.

Through our interpreters we learned that all Mr. Fish wants for his birthday is the companionship of a fish of the same species. He originally wanted a goldfish for a friend but the kids informed him that fish only get along with the same type of fish.

Insipired by the connection, Dawn and I want to write “Mr. Fish From Fish Phone” (The Musical). If you want to help, let us know. Don’t forget to say “Happy Birthday” to Mr. Fish on Friday the 18th. He’ll only turn two once!

My Latest Exhibit Crush

by ryan

While I’ve had some deep relationships with exhibits like turntable, the bubble tray, and catenary arch, no exhibit on the floor has been satisfying me lately like the musical drinking fountain. It just the perfect exhibit to show to visitors (whether in orientations or one-on-one). If you don’t believe me, I have six reasons why this little number has stolen a piece of my heart.

1. Its a simple concept and every part is transparent. The ehxibit makes musical tones when the circuit is complete and electricity can flows through the whole system.

2. Its fun to make songs by keeping one hand on the copper band and quickly poking the silver surface with one finger, producing a new and suprising note everytime depending on how much current can flow through that part of your hand.

3. Electricity can flow through people. So when one person touches the silver and one touches the copper…touching each other’s hands makes the musical tones. You can make some really sweet high fives.

4. This concept works with 17 or more people all linked together creating a chain. Most of the best exhibits at the exploratorium have to be used by more than one person at once.

5. Its probably one of the only exhibits where you really can use all 5 senses (wait…can you smell water?).

6. Its hidden as a functional object. I really like how it rewards those who have their eyes and ears open and are curious about everything around them, not just the labeled exhibits.

Has anyone else had any other cool experiences with this baby? Don’t worry, I won’t be jealous.

A world without colors

by Luigi Anzivino

A world without colors, originally uploaded on flickr.

This is a hard one to explain. Richard Brown, resident neuroscientist at the Exploratorium, had an exhibit for the Liminality party, called “A world without colors”. You walked into a room, and all of a sudden you were in a black and white movie: everything was monochromatic, a pale shade of yellow, and it was impossible to determine the color of anything. Very stunning sensation.

At the entrance of the room there was a rainbow-striped carpet: as you passed the threshold (the “limen”), the rainbow lost all its colors and became a collection of stripes in shades of gray. Posters on the wall looked like black ink etchings. There were big bowls of multi-flavored Jelly beans, and they all looked gray and black. It made it harder to identify the flavor, showing that taste is a very complex and multimodal perception, which relies on more than just the taste receptors on our tongues, but includes sight as well as smell. When we say that we eat with our eyes, it is literally (albeit partially) true.

How did it work? He flooded the room with low-vapor sodium lights, which put out only one frequency of light. Our brain can compute color by comparing the information that comes in from our three different types of cones (photoreceptors in the retina, the back of the eye). By flooding the visual scene with one frequency, this comparison is shortcircuited, and the brain interprets everything as monochromatic.

Another genius bit was that he had arranged a number of regular flashlights that you could pick up and go around the room shining a beam of full-spectrum light on objects. This brought back the colors only in the spot where the light shone. It was like having a magic wand that painted colors on the world.

He had also arranged colored markers and index cards, so that you could make a “black and white” drawing, then with the flashlight discover the colors in them. And a lot of other small details. It was a fascinating and fun room to spend some time in, albeit a little eerie and otherworldly.

Of course, digital cameras are not like our brains, so taking pictures did not work very well. They came out strongly dominant in the yellow, but the sense of monochromaticism was lost. So I photoshopped this image to reproduce the percept of what it felt like to be in the room. I think it came out relatively true to the experience.


by Luigi Anzivino

I like how much attention to details goes into every aspect of the museum. For example, take the entrance to the restroom. A more “lowly” part of the museum you couldn’t find. Yet there is an exhibit built into the very tiles of the entrance wall, known as the Cafe Wall illusion.

Deceptions, originally uploaded on flickr.

(Go ahead and click on the picture, and look at it large. Measure the lines with a ruler on your screen. They are really straight!)

The nice touch here, the attention to details, is the wall opposite the illusion, the back of the wall where the photographs hang, which you can’t see in the photo. The illusion is created by staggered black and white tiles with grout in between them that is an intermediate shade of gray. The wall opposite has the same tiles, organized in the same way, but with white grout between them, and they look perfectly straight.

So, in the rare occasion that there’s a line to the restroom, people can still look at something interesting while waiting, and with a bit of observant spirit they’ll figure out that the difference lies in the color of the grout, and learn something.