One-Time Donations for 2018

$1,350 of $2,500 raised

ChemThink – “The Behavior of Gases” is Here!

Category : Uncategorized · No Comments · by February 28, 2018

Great news!  “The Behavior of Gases” has been ported from Flash to HTML5.  This ChemThink tutorial took a lot of time to make, and it looks great!  All of the original controls are here, and the question set is as challenging as ever.  Students will adjust temperature, number of atoms, pressure, and volume to see how this affects the frequency and force of the collisions with the walls of the container.

If you have already donated to the site, thank you!  As of the time this writing, we are nearly halfway to meeting our yearly goal of $2500 to keep the site running.   If you have not donated yet, please consider donating., ChemThink, and rely on your support to pay for the cost of their web server.

Donate Today!

2018 Donation Drive for SimBucket, ChemThink, and QuizEvolved

Category : Uncategorized · No Comments · by February 13, 2018

Dear and users,

Last week I received an invoice from our web hosting company with a huge price increase for our servers. Up until this year, I have been able to pay for both sites with help from a few users, but with the price increase I can no longer afford the expense.

In order to ensure the financial stability of and, we are planning an annual donation drive. So far, we have collected the following donations for 2018:

$1,350 of $2,500 raised

Donate Today!

In addition to the donation drive:

1. I have consolidated all of our web services down to just two: a cloud-based VPS provider and Amazon Web Services. We now have a single, modern, powerful VPS that can easily handle all of the load for several hundred dollars cheaper per year than before.

2. At the end of 2018, I will review our income and expenses to make sure the websites are still financially viable.

Please donate today! If you are willing to donate for SimBucket, ChemThink, or QuizEvolved, please click here to continue to the donation form. With your help, I hope we can keep these sites free forever.

Chris Bruce
Physics Teacher, NBCT
Lead Developer,

3D Model Files for Physics Demos Shown at Physics Northwest

Category : High School, Middle School, Physics · No Comments · by November 17, 2017

We had a great evening of physics demos and discussions on Wednesday night.  Thanks to Marty (CHS), Dave (CHS), Caleb (CHS), Josh (PMSA), Kunal (HPHS), Bryan ( GBN), Mark (PHS), Mike (SHS), and Sasha (Northwestern University) for sharing.  The hosts were excited to give away 3D printed models of the “Accurate PVC Launcher”, “Moment of Inertia Spinner”, “Cheap Pulley”, and “Adjustable Frequency PVC Horn”.  All of the designs were built using the free website

If you have access to your own 3D printer, you can print your own!

Click on the images below for the model files and instructions for printing the “Accurate PVC Launcher”, “Moment of Inertia Spinner”, “Adjustable Frequency PVC Horn”, and the “Cheap Pulley”:

Adjustable Frequency PVC Horn on Thingiverse by David Torpe

Moment of Inertia Spinner on Thingiverse by Chris Bruce

Accurate Ball Launcher PVC on Thingiverse by David Torpe

Cheap Pulley on Thingiverse by Caleb Cochrum

New video – “Pendulum Energy Lab”

Category : High School, Physics · No Comments · by November 9, 2017

For the past few years in our regular physics classes, students have struggled to complete the “Pendulum Energy Lab”. This lab involved setting up a mass hanging from the ceiling by a string. Students were asked to shoot video of the mass as it swung back and forth. They then analyzed the video to compute potential energy and kinetic energy at various points during the swing. The problem was that to get the height and speed, they would have to set up multiple meter sticks at lots of different crazy angles, and then have to deal with blurry video. The lab that was designed to show a simple concept ended up being so complicated and taking so much time that most students completely missed the point.

This year we decided to shoot high-quality video of the lab to see if we could distill things down to their essence and eliminate the blurry meterstick mess.

The result is the new “Pendulum Energy Lab” video. Students must still measure height and speed, but this time the measuring devices are perfectly positioned and are easy to read. Students can easily scroll through the video to record height, position, and time. We have included a paper copy of the activity which prompts students to create a data table for potential and kinetic energy at various points, then to create energy bar graphs.  We are looking forward to trying the new lab in class on Monday!

Its Momentum Time! – Egg Drop and Bathroom Scale Videos Posted

Category : Physics · No Comments · by October 23, 2017
Its Momentum Time! – Egg Drop and Bathroom Scale Videos Posted

We are excited to announce two new momentum labs for Video Motion Analysis: “Egg Drop” and “Paper Towel Roll Dropped…

New Video Motion Analysis – “Battery Cannon”

Category : Uncategorized · No Comments · by October 12, 2017

The last few days have been rainy in Chicagoland, so we took advantage of the bad weather by launching our indoor air cannon. We have lovingly blasted all of our Nerf darts into oblivion, so yesterday we decided to launch a AA battery instead. We started small, using an 8-foot section of 1/2 inch PVC pipe as a blowgun. Using nothing more than lung power, we were able to launch the 24 gram battery at 22 meters per second. Although this is impressive, we figured that we could push the limits a little and hook up our pressurized air launcher to the PVC pipe. With the air launcher we were able to launch the battery at significantly higher speeds. We launched the “battery cannon” three times. Each time, the battery was safely “caught” by a box mounted to low-friction rails.

As always, we captured the motion of the battery and the box using the Edgertronic high speed camera. Our first shot was captured at 200 frames per second, but we realized that we would need to go to 1000 frames per second for higher launch speeds. The result is a series of videos that students can use to verify the Law of Conservation of Momentum.

Please note that our experimental setup wasn’t perfect, and the battery did ricochet off of the inside of the box, introducing a small but measurable increase in the speed of the box after the collision. This is a perfect opportunity to discuss imperfectly inelastic collisions.

We hope you enjoy the new videos, and please let us know if you are using them in your classroom.

Also, chemistry and biology teachers, we have found that the camera also works great for fast-moving explosions and insects. Please let us know if there is a potentially interesting phenomenon that you would like to see filmed in slow motion!

New Video Motion Analysis – “Tennis Ball Cannon”

Category : Physics · No Comments · by September 28, 2017

Today was a beautiful day, perfect for launching the tennis ball cannon on the football field. We had a lot of good shots, and took videos of two of them with an iPhone. The first video was shot from the goal line, and landed in the end zone on the other side of the field. The second shot was also shot from the goal line, but it landed well into the track on the other side, for a total distance of 145 yards!

We wrapped the videos up in the app, and have made them available for student analysis. Enjoy, and please let us know if you are using them in your classes!

New Video Motion Analysis – “Horizontal Atwood Lab”

Category : High School, Middle School, Physics · No Comments · by September 25, 2017

We just finished uploading six (really five, because we were able to reuse one of the scenarios) new high-speed videos for Video Motion Analysis called “Horizontal Atwood Lab”. We also put together a very simple lab activity to go with it, suitable for an introductory high school physics classes. In the activity, students analyze sets of three videos to determine the relationships between acceleration and total mass, and acceleration and force. Students should be able to finish the activity in about 30 minutes.

Now that the analysis apps are built, shooting new videos and uploading them goes fairly quickly. Let us know if you have any videos that you would like to see for your class!

Video Motion Analysis – New on!

Category : Biology, High School, Middle School, Physics · No Comments · by September 20, 2017

New Video Motion Analysis Apps on

We are pleased to announce “Video Motion Analysis“, a new set of apps on  Each app features one video shot with a high-speed camera.  Students can scroll through each frame and take careful measurements.  Some of the apps contain more advanced plotting, graphing, and analysis tools so that students can collect, plot, and analyze the data directly within the app.

We tried the “Ball Launched At An Angle” videos today with our students.  Using the graphing and slope calculation tools, they were quickly able to determine that horizontal acceleration is always zero, and vertical acceleration is always 9.8 m/s² downward, no matter which videos they selected for analysis.

We are continuing to shoot video, and hope to have many more videos available for analysis over the coming months.  If you have a physics lab that you do with your students and would like us to shoot video, please let us know.  We will do our best to recreate it for you and make it available on

The new Video Motion Analysis section can be found on the homepage, or via the following direct link.

ChemThink – Two New HTML5 Tutorials and Guest Mode

Category : Uncategorized · No Comments · by June 16, 2017

Covalent Bonding and Molecular Shapes For HTML5 Now Available!

The first piece of news may not be news to you at all! If you have particularly sharp eyes, you might have noticed that both “Molecular Shapes” and “Covalent Bonding” are now available in the HTML5 ChemThink web app. Although they should be fully functional at this point, we are still doing some tweaking and testing to make sure they are ready for students before the start of the coming school year.  Please let us know if you see any problems!

A Tetrahedral Molecule in 3D – From the new Molecular Shapes Tutorial

The Molecular Shapes tutorial has undergone a major overhaul since it was original created 15 years ago. The new version of the tutorial starts by visualizing the 3D location of each electron pair in a Lewis Dot diagram, then uses those locations to show “areas of electron concentration” in 3D (shown in dark yellow on the image above), and finally shows students the 3D space-filing model of each molecule.  With new 3D visualization and physics-based animations, students should be able to much more easily understand how and why molecules assume certain shapes.

With the inclusion of “Covalent Bonding” and “Molecular Shapes”, five of the original eleven ChemThink tutorials are now available on the ChemThink web app:

ChemThink server and database ✓ Done
Atomic Structure tutorial and questions HTML5 port ✓ Done
The Particulate Nature of Matter tutorial and questions HTML5 port ✓ Done
Ions tutorial and questions HTML5 port ✗ Flash Only, No Server or Database Connectivity
Ionic Formulas tutorial and questions HTML5 port ✗ Flash Only, No Server or Database Connectivity
Ionic Bonding tutorial and questions HTML5 port ✓ Done
Covalent Bonding tutorial and questions HTML5 port ✓ Done
Molecular Shapes tutorial and questions HTML5 port ✓ Done
Gas Laws tutorial and questions HTML5 port ✗ Flash Only, No Server or Database Connectivity
Isotopes tutorial and questions HTML5 port ✗ Flash Only, No Server or Database Connectivity
Chemical Reactions tutorial and questions HTML5 port ✗ Flash Only, No Server or Database Connectivity
Precipitates Lab Simulation HTML5 port ✗ Flash Only, No Server or Database Connectivity

“Guest Mode” Coming Soon – No Student Login Required!

The second piece of news is that this summer we will create “guest mode” for ChemThink.  I’m sure many of you have been frustrated when students forget their password and can’t log into ChemThink.  In many cases, students lose a good chunk of the period trying to login and navigate the system.  This is valuable time they could otherwise spend thinking about how atoms bond to each other or why molecules are formed in different shapes.  In order to reduce the amount of mental friction in the classroom, we are creating “guest mode”.  Guest mode should get students into the appropriate tutorial or question set immediately — no student login required!

Guest mode is still evolving as a concept, but we should have a basic version of it up and running in the next week or two, and it should be completely ready to go by the beginning of August.  We will put out an announcement when it is ready.

Please Consider Supporting ChemThink with a Donation

ChemThink still needs your support!  Please consider donating to help defray server costs.  To donate, click on the paypal button below, or send an email to

(c) 2014 Nerd Island Studios, LLC