Field Trip Explainers

Reflections on life at Exploratorium

Observatory Study Group – Special Places in the Bay Area

by lapinehorizon


This is an example of the group project we did, about personal places that we would like to share (or not, maybe.) This is the only visual I could manage to upload. The rest of them are in possession of Explainers, on physical paper.

Settling Plate Experiments Begin!

by rbehnam

Several weeks ago we finiished building and installing settling plates around Pier 15 in an effort to continue Karen Kalumuck’s experiments, formerly known as Dock Schmutz. This name affectionately refers to all the amazing creatures that grow on side of the docks in our bay. In more scientific terms, these creatures are known as intertidal invertebrates, and include both plant-like and animal-like organisms.

We decided to make our plates using PVC plastic, wood, and metal, and to hang them along the pier on both sides to see if we noticed any differences between the creatures on either side. And it wouldn’t be an Explainer experiment if we didn’t give each plate a strange name. So, the eight plates are named as follows:

1. The Old City – an entirely PVC plate that was installed prior to our official move to the piers by Karen. We estimate it was attached in the fall of 2012.

2. Boris – a series of two wood plates. Unfortunately, we somehow lost Boris a week ago and have to build a Boris #2.

3. Triplet City – a series of three, small PVC plates installed just outside the tinkering studio.

4. Rainbow City – Our only plate containing wood, PVC and metal layers, on the southwest corner of the pier.

5. Rusty Heartbeat – three metal and one pvc plate. Two of the metal plates are perforated with many holes. This plate is nearest to the gates by the Seaglass Restaurant.

6. Root Canal City – One of the older plates that was installed at the same time as The Old City, but is on the north side of the pier. Interestingly, the life growing on this plate looks very different from its brother plate on the south side.

7. Dedo Muerte City – a stacking series of both clear and white PVC plates hanging at the end of the echo tube.

8. Delicious Pineapple City – three wood plates hanging in the plaza, near Disappearing Rings.


Here is an example of the drastic changes we are seeing. Triplet City went from this,


to this,


in a matter of weeks!

And sometimes, very interesting things happen where we least expect it, like on the rope or bucket rather than on the plate itself. Here is a black limpet that has found a good home on the bucket of Rainbow City:


We are excited to see what will become of our plates! As they have only been hanging for a month, the biggest changes we have noticed is how quickly they become covered with black, brown and green sludge of all kinds. The Old City seems to represent the great diversity of creatures that could potentially grow on our plates, including tunicates (both solitary and colonial), skeleton shrimps, worms of all kinds, barnacles, mussels, scallops, limpets, bryozoa, and a variety of seaweeds.

Here are some thoughts and questions that have arisen in our notes and observations over the last month:

  • How much biomass is there? And how fast is it growing?
  • What is all this slime, mud, sludge really made of? Is it of any value?
  • Why do some of the buoy buckets get covered more than the plates?
  • What happened to Boris?
  • Are those long, spindly, pinkish seaweed things with bulbs on the end plants or animals?
  • Do creatures have trouble attaching to the smooth, metal plates?




Circuit Inspiration

by Julie C.

Explainers spend a fair amount of time in the Tinkering Studio playing with Circuit Boards. We connect motors to batteries; compare series and parallel circuits; and experiment with types of switches. Visitors join us throughout the day to create their own circuits.

But, what is an electric circuit?

An electric circuit is “a complete conducting loop from the positive terminal to the negative terminal [of a battery], with both the battery and the light bulb [or other component] being part of the loop.” *

blog circuits circuit

But not all circuits are so simple… Read the rest of this entry »

Explainer Recipes

by Julie C.

Allison has collected the culinary wisdom of Explainers. From herbivores to carnivores and complicated to simple, here is the result. Click through for all of our recipes or add your own in the comments!



Robert, Ham Sandwich:
Bread (not necessary)

Read the rest of this entry »

Pianos and Proprioception

by Julie C.

A few weeks ago we experimented with our sense of proprioception. Proprioception is the sense of where our bodies are in space and how much force we need to use to move them. If your sense of proprioception is impaired you may talk too loudly, press a pencil hard onto paper, or grasp things too forcefully. Going through a growth spurt often temporarily impairs one’s proprioception, which is why adolescents tend to knock into things.

We tested our own senses of proprioception with blind drawing. We sat in the West Gallery and took five minutes to draw the exhibits around us. The only rule was no looking at our paper while we did it. A few people drew the same exhibit. Can you tell which one it is?



Read the rest of this entry »

Camera, Camera on the wall, who’s the hottest of them all?

by nlcarlson

If you have ever stood next to another human being, then you probably felt some body heat radiating from her. What you might not realize is that everything emits radiation: you, your dog, your chair. Everything! (see this article:

Explainers play in the infrared camera with ice and hot water. Photo courtesy of Sylvia Algire*

Now you are probably asking yourself “Am I the same as a chair?”. While only you can truly answer that question, for the purposes of this blog post, the answer is “no”. The key difference is that you and your chair radiate different amounts of energy.

Physicists model objects that radiate heat as black bodies. A black body is an idealized object that absorbs all energy (specifically, electromagnetic radiation) that hits it. A black body will emit radiation in a way that is solely determined by its temperature. The emitted radiation is described by Planck’s Law. Note: only click on the link if you can handle lots of maths.

Thus, if we could measure the radiation emitted by a black body, we could determine the object’s temperature. Luckily, the world we live in has such measuring devices: infrared cameras!

An infrared camera measures the infrared radiation emitted by objects and then calculates the apparent temperature of each object. The objects are then colored based on their temperatures (see attached photos for some examples).

However, real objects are not black bodies because they only absorb part of the energy that hits them while the rest of the energy is reflected. The percentage of energy that an object emits back is defined as the object’s emissivity. Therefore, if the emissivity of an object is known, the camera can correctly estimate the temperature of the object and produce an amazing picture.

Photo courtesy of Sylvia Algire*

In short, infrared cameras give us an opportunity to see into a completely different world. Now that you’re done reading, go play in front of an infrared camera with hot water, dry ice, and your own body.

To learn more about the nitty gritty details of infrared cameras, look up Thermography. Thermography is the field dedicated to infrared imaging including measuring radiation and estimating/measuring emissivities. Thermographers (I totally made up this word) develop fancy algorithms and methods for calibrating infrared cameras. If you are interested in reading more about thermography, check out these links:

  • Short-wave infrared camera picture of mock-dead Explainers. Photo courtesy of Jenny Situ*

    *All pictures were taken with the infrared camera or short-wave infrared camera at the Exploratorium ( during a Field Trip Explainer training session.

    ** Apologies to any physicists reading this post if I simplified things too much!

    Image | January 29, 2014

    by Julie C.


    This is a comic that Allison drew . It’s a funny comic and a true story!   The broken piano was turned into the exhibit, Piano Strobe. A strobe light is directed at the exposed strings of the piano. If the strobe flashes at the same speed that a string is vibrating, the string will appear […]

    November 20, 2013

    Seeing Polarized Light

    by nlcarlson

    “Once you see it, you can’t unsee it”

    Earlier this fall, I conversed with Julie about what superpower we would choose. She mentioned that she and Rob were interested in learning how to see different types of light. I immediately grew excited because this seemed like an attainable superpower. I decided to focus on seeing polarized light.

    During my search, I even found a website that listed seeing polarized light as a useless superpower ( My search ended with Haidinger’s Brush (, the manifestation of how humans see polarized light.

    Haidinger’s brush is a visual phenomenon seen in polarized light that looks like a yellow bowtie with a blue bowtie perpendicular to it (see Figure 1). People do not usually see it naturally, but most can train themselves to detect it. The easiest way to see the brush is on the white screen of an LCD monitor (for example, you could use the computer that you reading this blog post on). Be warned though, once you train yourself to see it, you will probably see it on every future computer that you look at.

    Open source image of Haidinger’s brush from Wikipedia

    After this initial research, I quickly coerced my study group into investigating this phenomenon. We initially tried staring at blank Safari tabs on iPads. Hartley was the first to reach success, but Raquel and I needed some extra help. We decided to go on a search for polarizing filters in the museum.

    During our trip to the shop with Kate, we fortuitously ran into the museum’s neuroscientist, Richard Brown. He immediately knew what we were talking about and agreed to help us out. He gave us some tips on ways to train our eyes, and he also mentioned that some light-eyed people might never be able to see the brush (take that recessive genes).

    Richard’s main tip was to try rotating the iPad smoothly while looking at it from a distance. We achieved this by using a turntable provided by Kate and standing on the Explainer Hub table. Soon Raquel, Kate, and I were able to see a rotating yellow brush. Hartley claimed that he could also see the blue bowtie as well, but this claim has yet to be verified.

    We decided to share our newfound powers with the other Explainers during our Friday meeting. Although I had to miss that training, Raquel and Hartley reported back that some Explainers were able to see the brush. Unfortunately, Julie was not one of them; she’ll have to find her own superpower.

    Overall, I am ecstatic that I have succeeded in turning myself into a superhero. The next challenge is training myself to see Haidinger’s brush in the sky. And like every superhero, I’ve already obtained a supervillian: the rain in San Francisco is deliberately thwarting my attempts to see the brush in the sky.

    November 13, 2013

    Happy Halloween from the Explainers!!!

    by salamandersal

    DSC_0099DSC_0104 DSC_0109 DSC_0113 DSC_0118 DSC_0121 DSC_0122 DSC_0131 DSC_0148 DSC_0152 DSC_0153 DSC_0157 DSC_0158 DSC_0162 DSC_0155 DSC_0128

    Video | October 30, 2013

    Cloudy With a Chance of Joy

    by klstirr

    We have been pretty excited about clouds ever since we began plotting our cloud demo several years ago, but our energy around clouds has been supercharged by Gavin Pretor-Pinney and his Cloud Appreciation Society. One of my favorite quotes from his TED talk posted above echoes something that is one of my goals for visitors (and for myself) in many of our demos and interactions at the Exploratorium: as Gavin says, “You don’t need to rush off away from the familiar, across the world, to be surprised—you just need to step outside, pay attention to whats so commonplace, so everyday, so mundane, that everybody else misses it.”

    His talk, and the Cloud Appreciation Society as a whole, remind us that we are not separate from our atmosphere—”we don’t live beneath the sky, we live within it,” and that “cloudspotting legitimizes doing nothing…and reminds us that just being here and letting your imagination lift from the concerns…of just being in the present is good for you—its good for the way you feel, its good for your ideas, its good for your creativity, [and] its good for your soul.”

    So, look up at the clouds & find joy in being here in the world!


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