Category Archives: Main Blog

New features in CODAP

Our Common Online Data Analysis Platform (CODAP) software provides an easy-to-use web-based data analysis tool, geared toward middle and high school students, and aimed at teachers and curriculum developers. CODAP is already full of amazing features. We’re excited to announce several new features! Continue reading

Why is Israel building the world’s tallest solar tower?

Fig. 1: Something tall in Negev desert (Credit: Inhabitat)
The Ashalim solar project (Figure 1) in the Negev desert of Israel will reportedly power 130,000 homes when it is completed in 2018. This large-scale project boasts the world’s tallest solar tower -- at 250 meters (820 feet), it is regarded by many as a symbol of Israel’s ambition in renewable energy.

Solar thermal power and photovoltaic solar power are two main methods of generating electricity from the sun that are somewhat complementary to each other. Solar tower technology is an implementation of solar thermal power that uses thousands of mirrors to focus sunlight on the top of a tower, producing intense heat that vaporizes water to spin a turbine and generate electricity. The physics principle is the same as a solar cooker that you have probably made back in high school.

Why does the Ashalim solar tower have to be so tall?

Surrounding the tower are approximately 50,000 mirrors that all reflect sun beams to the top of the tower. For this many mirrors to "see" the tower, it has to be tall. This is easy to understand with the following metaphor: If you are speaking to a large, packed crowd in a square, you had better stand high so that the whole audience can see you. If there are children in the audience, you want to stand even higher so that they can see you as well. The adults in this analogy represent the upper parts of mirrors whereas the children the lower parts. If the lower parts cannot reflect sunlight to the tower, the efficiency of the mirrors will be halved.

Fig. 2: Visualizing the effect of tower height
An alternative solution for the children in the crowd to see the speaker is to have everyone stay further away from the speaker (assuming that they can hear well) -- this is just simple trigonometry. Larger distances among people, however, mean that the square with a fixed area can accommodate less people. In the case of the solar power tower, this means that the use of the land will not be efficient. And land, even in a desert, is precious in countries like Israel. This is why engineers chose to increase the height of tower and ended up constructing the costly tall tower as a trade-off for expensive land.

Fig. 3: Daily output graphs of towers of different heights
But how tall is tall enough?

Fig. 4: Energy output vs. tower height
This depends on a lot of things such as the mirror size and field layout. The analysis is complicated and reflects the nature of engineering. With our Energy3D software, however, complicated analyses such as this are made so easy that even high school students can do. Not only does Energy3D provide easy-to-use 3D graphical interfaces never seen in the design of concentrated solar power, but it also provides stunning "eye candy" visualizations that clearly spell out the science and engineering principles in design time. To illustrate my points, I set up a solar power tower, copied and pasted to create an array of mirrors, linked the heliostats with the tower, and copied and pasted again to create another tower and another array of mirrors with identical properties. None of these tasks require complicated scripts or things like that; all they take are just some mouse clicks and typing. Then, I made the height of the second tower twice as tall as the first one and run a simulation. A few seconds later, Energy3D showed me a nice visualization (Figure 2). With only a few more mouse clicks, I generated a graph that compares the daily outputs of towers of different heights (Figure 3) and collected a series of data that shows the relationship between the energy output and the tower height (Figure 4). The graph suggests that the gain from raising the tower slows down after certain height. Engineers will have to decide where to stop by considering other factors, such as cost, stability, etc.

Note that, the results of the solar power tower simulations in the current version of Energy3D, unlike their photovoltaic counterparts, can only be taken qualitatively. We are yet to build a heat transfer model that simulates the thermal storage and discharge accurately. This task is scheduled to be completed in the first half of this year. By that time, you will have a reliable prediction software tool for designing concentrated solar power plants.

Learning Everywhere taking inspiration from two partners, At-Bristol and Exploradôme

Innovative applications of technology are found virtually everywhere, transforming all kinds of spaces into opportunities for STEM learning that move beyond the walls of classrooms and past schooltime hours. Persistent engagement and interest in meaningful learning activities and practices can spur an enduring pursuit of science.

Our Learning Everywhere initiative is exploring, prototyping, and creating new learning experiences—including exhibits, mobile apps, and user tracking technologies—that connect and coordinate learning across museums and bridge in-school and out-of-school time. To survey new learning spaces and interactive technologies, we visited two of our Learning Everywhere partners, At-Bristol and Exploradôme, as well as other science centers in the London and Paris areas, including the Science Museum of London and the City of Science and Industry at La Villette.

Chad Dorsey and Sherry Hsi at the entrance of At-Bristol Science Center.

Chad Dorsey and Sherry Hsi at the entrance of At-Bristol Science Center.

Donning our bracelets printed with unique barcode IDs at the entrance, we explored the many At-Bristol exhibits, scanning our bracelets to collect and compare our data with data from other visitors. At some stations, we learned how the creators of Wallace and Gromit, from Aardman Animations’ studios also in Bristol, made their great movies before creating our own stop-motion animations. A quick scan of our wrists saved these animations to a website where we could access them later. Other parts of our experience, from scatterplots of our height compared to other visitors to videos of ourselves on slow-motion “startle-cam” added themselves into our electronic portfolio during the visit. We even found ourselves wearing bee wings and performing a waggle dance to mimic bee behaviors in an exhibit about the mysterious lives of bees! This and other digital artifacts from our visit served as opportunities for further conversation and inquiry back home, and as a source of fun for our families. (Needless to say, the bee dance video was a source of great enjoyment, but it will not be showing up publicly on Instagram any time soon!)

At-Bristol Science Center’s animation exhibits area.

At-Bristol Science Center’s animation exhibits area.

Our visit to London coincided with the grand opening of Wonder Lab at the Science Museum of London. Our guide, Dave Patten, Head of New Media there, showed us the spacious, colorful interactive gallery designed to encourage visitors to collaborate, play, and learn from conversation. In another exhibition, Engineer Your Future, teens and young adults use their personal mobile devices in public gallery spaces to design vehicles, then launch and control them on a huge public screen! Other large-screen and combined physical-digital exhibits featured different design-oriented and competitive games on energy, vehicle design, and different engineering careers.

Science Museum of London’s WonderLab the evening before its grand opening.

Science Museum of London’s WonderLab the evening before its grand opening.

The many heads of Dave Patten from the Science Museum of London in a Wonder Lab exhibit.

The many heads of Dave Patten from the Science Museum of London in a Wonder Lab exhibit.

Moving farther south, we visited the Cité des Sciences et de l’Industrie in Paris, where an immense, airy space houses corners with multiple galleries of permanent and temporary exhibitions. Among them, designed areas invite reflection and discussion among school groups or individuals. In a highlight of the visit, François Vescia, Senior International Project Manager at the museum, gave us a tour of their fabrication laboratory, Carrefour Numerique. This public space is a wonderland of design and making, custom created to invite design collaboration and discussions that merge seamlessly into design and construction of physical prototypes and objects. Visitors access materials and machinery from e-textile design, milling machines, 3D printers, and laser and vinyl cutters to turn their visions into reality. Drop-in and scheduled programs and workshops and in-person support are available, and visitors can begin designing projects digitally in the multimedia lab, then move next door to fabricate them.

Chad Dorsey, Francois Vescia, and Sherry Hsi at Parc de la Villette, an area in Paris, known for the Cité des Sciences et de l'Industrie science museum.

Chad Dorsey, Francois Vescia, and Sherry Hsi at Parc de la Villette, an area in Paris, known for the Cité des Sciences et de l’Industrie science museum.

Entrance to the Fab Lab at the City of Sciences and Industry in Paris.

Entrance to the Fab Lab at the City of Sciences and Industry in Paris.

Taking the train to the southern suburbs of Paris, we visited the Exploradôme, where we met Goery Delacote, its founder and a longstanding member of the Concord Consortium Board of Trustees. Goery toured us among the great exhibits packed into the floor of this small museum, where the motto is “Not touching is not allowed!” Playing like kids (and some of us were!), we explored visual perception phenomena, dug holes for water in a version of the AR Sandbox Sherry helped create and worked together to launch six-foot smoke rings that rose to the ceiling.

Goery Delacôte, Sherry Hsi, and Chad Dorsey at the entrance of Exploradome in Vitry-sur-Seine south east of Paris. Colors from the building were selected from colors found around the local neighborhood.

Goery Delacôte, Sherry Hsi, and Chad Dorsey at the entrance of Exploradome in Vitry-sur-Seine south east of Paris. Colors from the building were selected from colors found around the local neighborhood.

The thoughtful curation and orchestration of interactive exhibits throughout our Learning Everywhere tour was inspiring, as was the innovative use of technology to engage visitors and extend museum experiences beyond the visit. As we collate and catalog these experiences and technologies as part of the project work, we look forward to working further with museums and other out-of-school institutions to bridge and extend learning everywhere.

Making smoke rings collaboratively at the Exploradome with Goery Delacôte and Sherry Hsi.

Making smoke rings collaboratively at the Exploradome with Goery Delacôte and Sherry Hsi.

Making virtual lakes by digging in the Augmented Reality Sandbox exhibit at the Exploradome.

Making virtual lakes by digging in the Augmented Reality Sandbox exhibit at the Exploradome.

Exploring optical illusions and visualization puzzles at the Exploradome with Goery Delacôte.

Exploring optical illusions and visualization puzzles at the Exploradome with Goery Delacôte.

By Popular Demand: Printable NGSS Pathfinder

The Next Generation Science Standards (NGSS) provide a framework and examples of three-dimensional learning. Soon after they were released, we created the NGSS Pathfinder to help educators find their way through the core ideas, crosscutting concepts, and science and engineering practices that make up the NGSS. This intuitive tool allows you to consider some of the myriad paths possible, and links to free Concord Consortium resources for any given path.

NGSS Pathfinder

We’ve had lots of positive feedback about the NGSS Pathfinder, including many requests for a printable version. And since we love to give educational resources away for free, we’ve made a printable version of the Pathfinder available. Feel free to use it for handouts, full-size posters, or anything else. We’re especially excited about the idea of people creating laminated posters so they can draw their own paths!

As always, you can continue to use the online NGSS Pathfinder to create interactive links from core ideas to science and engineering practices and crosscutting concepts, and get access to free resources for your selected path. Our computational models and probe-based activities bring important learning within new reach. Students using such technology-based activities also gain wide experience with crosscutting concepts—from scales in space and time to energy and systems—across domains in science, math, and engineering.

The NGSS Pathfinder graphics are licensed under the Creative Commons Attribution 4.0 license (CC BY 4.0), so you’re welcome to use them under those terms. If you share the graphics online, please attribute the Concord Consortium and include a link to

Geological models to help students explore the Earth

Geoscience poses many questions. Why are there continents and oceans? How do mountains form? Why do volcanoes form in some areas and not others? What causes earthquakes to be more frequent in some areas than others? Why are oil, diamond, gold, and other deposits clustered in particular areas rather than being spread evenly across the world?

Teaching geoscience poses significant challenges. Experiments with Earth’s geology are impossible, and many of the natural processes that shape Earth, such as sedimentation, folding, and faulting, take place out of sight, over unimaginably long time periods. We think that technology has the potential help to transform how geoscience is taught and understood.

From the people who brought you High-Adventure Science comes the GEODE (Geological Models for Explorations of Dynamic Earth) project. Funded by the National Science Foundation, the new project aims to design dynamic, interactive, computer-based models and curricula to help students understand how Earth’s surface and subsurface features are shaped. As in the High-Adventure Science modules, GEODE modules will incorporate real-world data and computational models, with a focus on making scientific arguments based on evidence.

The GEODE  project, a partnership between the Concord Consortium and The Pennsylvania State University, held a kickoff brainstorming session Monday, September 27. Principal Investigator Amy Pallant and Co-PI Hee-Sun Lee, both of the Concord Consortium, and Co-PI Scott McDonald of Penn State organized a meeting to begin developing a plate tectonics model to accompany the recently developed Seismic Explorer.

In Seismic Explorer, students can see patterns of earthquake data, including magnitude, depth, location, and frequency.

In Seismic Explorer, students can see patterns of earthquake data, including magnitude, depth, location, and frequency.


Students can make a cross-section to see a three-dimensional view of the earthquakes in an area.

Professional geologists, geoscience educators, and software developers reviewed the currently available models and simulations of plate motion, earthquake waves, sedimentation, folding, and faulting, and discussed ways to make these concepts accessible to middle and high school students.

We look forward to sharing more models and activities as they are developed over the next few years!

Designing solar farms and solar canopies with Energy3D

Fig. 1: Single rack
Many solar facilities use racking systems to hold and move arrays of solar panels. Support of racks is now available in our Energy3D software. This new feature allows users to design many different kinds of solar farm, solar park, and solar canopy, ranging from small scale (a few dozen) to large scale (a few thousand).

Fig. 2: Multiple racks
Mini solar stations often use a single rack to hold an array of solar panels (Figure 1). This may be the best option when we cannot install solar panels on the building's roof. You probably have seen this kind of setup at some nature centers where the buildings are often shadowed by surrounding trees.

If you have more space, you probably can install multiple racks (Figure 2), especially when you are considering using altazimuth dual-axis solar trackers to drive them. This configuration is also seen in some large photovoltaic power stations.

Fig. 3: Rack arrays
Larger solar farms typically use arrays of long racks (Figure 3). Each rack can be driven by a horizontal single-axis tracker. Using taller racks usually requires larger inter-rack spacing, which may be an advantage as it allows maintenance trucks to drive through. In a recent experiment, SunPower experimented with how to grow crops or raise animals in the inter-rack space with their Oasis 3.0 system. So arrays of taller racks may be desirable if you want to combine green energy with green agriculture.

Fig. 4: Solar canopy above a parking lot
If you raise the height of a rack, it becomes a so-called solar canopy that provides shading for human activities like the green canopies of trees do. The most common type of solar canopy converts parking lots into power stations and provides shelters from the sun for cars in the summer (Figure 4).

Designing solar canopies for schools' parking lots may be a great engineering project for students to undertake. This is being integrated into our Solarize Your School Project. In fact, Figure 4  shows a real project in Natick High School in Massachusetts. The hypothetical design has more than 1,500 solar panels (each of them has the size of 0.99 x 1.96 m) and costs over a million dollars.

National Science Foundation funds chemical imaging research based on infrared thermography

The National Science Foundation (NSF) has awarded Bowling Green State University (BGSU) and Concord Consortium (CC) an exploratory grant of $300 K to investigate how chemical imaging based on infrared (IR) thermography can be used in chemistry labs to support undergraduate learning and teaching.

Chemists often rely on visually striking color changes shown by pH, redox, and other indicators to detect or track chemical changes. About six years ago, I realized that IR imaging may represent a novel class of universal indicators that, instead of using  halochromic compounds, use false color heat maps to visualize any chemical process that involves the absorption, release, or distribution of thermal energy (see my original paper published in 2011). I felt that IR thermography could one day become a powerful imaging technique for studying chemistry and biology. As the technique doesn't involve the use of any chemical substance as a detector, it could be considered as a "green" indicator.

Fig. 1: IR-based differential thermal analysis of freezing point depression
Although IR cameras are not new, inexpensive lightweight models have become available only recently. The releases of two competitively priced IR cameras for smartphones in 2014 marked an epoch of personal thermal vision. In January 2014, FLIR Systems unveiled the $349 FLIR ONE, the first camera that can be attached to an iPhone. Months later, a startup company Seek Thermal released a $199 IR camera that has an even higher resolution and can be connected to most smartphones. The race was on to make better and cheaper cameras. In January 2015, FLIR announced the second-generation FLIR ONE camera, priced at $231 in Amazon. With an educational discount, the price of an IR cameras is now comparable to what a single sensor may cost (e.g., Vernier sells an IR thermometer at $179). All these new cameras can take IR images just like taking conventional photos and record IR videos just like recording conventional videos. The manufacturers also provide application programming interfaces (APIs) for developers to blend thermal vision and computer vision in a smartphone to create interesting apps.

Fig. 2: IR-based differential thermal analysis of enzyme kinetics
Not surprisingly, many educators, including ourselves, have realized the value of IR cameras for teaching topics such as thermal radiation and heat transfer that are naturally supported by IR imaging. Applications in other fields such as chemistry, however, seem less obvious and remain underexplored, even though almost every chemistry reaction or phase transition absorbs or releases heat. The NSF project will focus on showing how IR imaging can become an extraordinary tool for chemical education. The project aims to develop seven curriculum units based on the use of IR imaging to support, accelerate, and expand inquiry-based learning for a wide range of chemistry concepts. The units will employ the predict-observe-explain (POE) cycle to scaffold inquiry in laboratory activities based on IR imaging. To demonstrate the versatility and generality of this approach, the units will cover a range of topics, such as thermodynamics, heat transfer, phase change, colligative properties (Figure 1), and enzyme kinetics (Figure 2).

The research will focus on finding robust evidence of learning due to IR imaging, with the goal to identify underlying cognitive mechanisms and recommend effective strategies for using IR imaging in chemistry education. This study will be conducted for a diverse student population at BGSU, Boston College, Bradley University, Owens Community College, Parkland College, St. John Fisher College, and SUNY Geneseo.

Partial support for this work was provided by the National Science Foundation's Improving Undergraduate STEM Education (IUSE) program under Award No. 1626228. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Early start in educational research

New York Times Clipping

Paul Horwitz, senior scientist, got his start in research earlier than most — when he was three! We’ve enjoyed his stories for many years. This one was too good not to share. One day at lunch we decided to follow up on his memories and dig a little deeper. We contacted Lindsey Wyckoff at Bank Street College, who sent us this story from their archives. Here is Paul’s story:

It’s July 1942. Hitler’s armies have conquered most of continental Europe and are about to unleash their fury on the Russian city of Stalingrad. England has survived the “blitz” but thousands of frantic British parents have allowed their children to be evacuated, some as far away as Canada. In New York the Bank Street Nursery School, under the auspices of the Office of Civilian Defense, has embarked on an ambitious experiment. Forty-five preschool children, ages two to five, will be “evacuated” for six weeks to Lake Waneta in upstate New York in order to evaluate whether the trauma of being separated from their parents outweighs the risk of exposing them to possible attack.

I was one of those children.

I was three and a half, far too young to understand what was happening to me, much less why, but the weeks I spent at “camp” that year are among my earliest memories. And the memories, by and large, are good ones.

I remember being introduced to a special kind of photosensitive paper that could record the silhouettes of objects placed upon it. I remember kicking my legs in shallow water, thinking guiltily that I had tricked my parents into believing I could swim. I have a hazy memory of a newsreel crew with a huge camera that moved back and forth on wheels.

I have no recollection of the battery of psychological tests that must have been run on me, though I do remember my answer to one question: in a race would you rather be first or last? (I chose last, on the basis that that way I wouldn’t always be looking behind me to see whether someone was catching up.)

I have since learned that the experiment was a success: given proper care, including cuddle time as well as meals, young children proved unexpectedly resilient. So no permanent damage was done, though I very much doubt that one could attempt this kind of thing today. In the end, as we know now, no evacuation of New York or any other American city was deemed necessary. The broad Atlantic and the absence of aircraft carriers from the German fleet offered protection enough in that long ago time. But today, as we learn to cope with sporadic and unpredictable violence resulting from a protracted “war on terror,” it is perhaps instructive to remember that we have survived much worse.

Modeling horizontal single-axis solar trackers in Energy3D

In the last post, I have blogged about modeling dual-axis solar trackers in Energy3D. To be more precise, the trackers shown in that blog post are altitude-azimuth (Alt/Az), or altazimuth trackers, or AADAT in short. In this post, I will introduce a type of single-axis tracker -- the horizontal single-axis tracker, or HSAT in short.

Fig. 1 Solar panel arrays rotated by HSATs
Because single-axis trackers do not need to follow the sun exactly, there are many different designs. Most of them differ in the choice of the axis of rotation. If the axis is horizontal to the ground, the tracker is a HSAT. If the axis is vertical to the ground, the tracker is a vertical single-axis tracker, or VSAT in short. All trackers with axes of rotation between horizontal and vertical are considered tilted single-axis trackers, or TSAT in short. None of these single-axis trackers can help the solar panels capture 100% of the solar radiation that reaches the ground. Exactly which design to choose depends on the location of the solar farm, among other consideration such as the cost of the mechanical system.

Fig. 2 Compare daily outputs of HSAT, AADAT, and fixed in four seasons.
HSAT is the first type of single-axis tracker that has been implemented in Energy3D. HSAT is probably more common than VSAT and TSAT and is probably easier to construct and install. In most cases, the rotation axis of a HSAT aligns with the north-south direction and the solar panels follow the sun in an east-to-west trajectory, as is shown in the YouTube video embedded in this post and in Figure 1.

Fig. 3 Compare annual outputs of HSAT, AADAT, and fixed.
How much more energy can a HSAT help to generate? Figure 2 shows the comparison of the outputs of a HSAT system, an AADAT system, and an optimally fixed solar panel on March 22, June 22, September 22, and December 22, respectively, in the Boston area. The results suggest that the HSAT system is almost as good as the AADAT system in June but its performance declines in March and September and becomes the worst in December (in which case it can only capture a little more than half of the energy harvested by the AADAT system). Interestingly, also notice that there is a dip at noon in the energy graphs for March, September, and December. Why so? I will leave the question for you to figure out. If you have a hard time imagining this, perhaps the visualizations in Energy3D can help.

Fig. 4 Compare wide- and narrow-spacing of HSAT arrays
Figure 3 shows the annual result, which suggests that, over the course of a year, the HSAT system -- despite of its relatively unsatisfactory performance in spring, fall, and winter -- still outperforms any fixed solar panel, but it captures about 86% of the energy captured by the AADAT system.

An important factor to consider in solar farm design is the choice of the inter-row spacing to avoid significant energy loss due to shading of adjacent rows in early morning and late afternoon. But you don't want the distance between two rows to be too far as the rows will occupy a large land area that makes no economic sense. With Energy3D, we can easily investigate the change of the energy output with regard to the change of the inter-row spacing. Figure 4 shows the gain from HSAT is greatly reduced when the rows are too close, essentially eliminating the advantages of using solar trackers. Despite of their ability to track the sun, HSATs still require space to achieve the optimal performance.

Solar Engineering Summer Camp 2016

Computer modeling with Energy3D
The free Solar Engineering Summer Camp offered by the Concord Consortium was an intensive week-long event that focused on learning and applying solar science, 3D modeling, and engineering design. It featured a solar engineer from a leading solar company as a guest speaker. The activities included hands-on and computer-based activities that were designed to inspire and empower children to solve real-world problems and become change makers who will hopefully create a more sustainable future.

Poster session with parents
This year, eleven children (age 11-16) participated in the event that took place on Concord Consortium's east coast campus. Participants became the science advisors for their parents, investigating how their own houses could be turned into a small power station that supplies the energy needed.

A 3D house created and studied in the event
Using Google Earth and our Energy3D software, they made 3D computer models of their own houses, designed different solar array layouts, and then ran computer simulation to evaluate and compare their yields. They performed cost-benefit analysis of different solutions, based on which they completed solar assessment reports about the solarization potential of their own homes. At last, they presented their results in a poster session and discussed their findings with their parents.

The parents were generally very supportive. Some even helped their kids measure the dimensions of their houses (unfortunately, Google Earth does not provide sufficient information for students to retrieve the geometry of their houses; so some kids must learn how to measure the heights of their roofs using other methods such as photogrammetry).

3D houses created by kids
How did the little science advisors do their jobs in terms of informing their parents then? When asked "Did your child’s Solar Assessment Report make you change your view or interest in solar energy?", a parent responded in the exit survey: "We already have solar panels on our house. This project allowed me to consider our energy needs and additional options for increasing our capacity to generate electricity." This example shows that even for those people who already have solar panels on their roofs, the findings from their kids might have spurred them to think about more possibilities.

As a side note, I noticed an interesting response from a parent: "She enjoyed using the software to design our house. She said it was an interesting topic, but she cautioned me not to rely solely on her calculations to base our decision on whether to convert to solar energy use for our house." The kid is right -- all models have limitations and engineers must use caution. A science advisor should inform her advisee that a model may fail.