Staying home during COVID means teachers and students have to get creative. Things that you would normally have at school you might not have at home and vice versa. A few days ago I decided to see if I could make a homemade “force plate” that could accurately measure impact forces. My smartphone has a high speed camera. I just needed something that was sensitive enough that it could measure tiny forces happening over very short periods of time.
My solution is shown above. To build it you will need:
Assemble your force plate as shown above. Adjust the height of the stick such that the laser beam hits the middle of it.
To measure static forces, press on the plate. As you press the laser beam will move across the stick. You can use a ruler and some known weights to calibrate your stick.
To measure impact, download a suitable video analysis app to your smartphone. For iPhones and iPads the “Technique” app by HUDL works well. I used Technique and a homemade force plate to create the latest Video Motion Analysis activity, “Measuring The Force Of Impact Over Time“. In the activity students learn how padding minimizes the force of impact.
Feel free to share and comment below!
It has been a super-productive week, and I just finished the port of “Ionic Formulas” from Flash to HTML5. The new HTML5 version is identical to the Flash version, and shows how we name ionic compounds. Because it runs in HTML5, it should work on any modern browser.
If you have already donated to the site, thank you! As of the time this writing, we are almost 80% of the way to our yearly goal of $2500 to keep the site running. If you have not donated yet, please consider donating. www.simbucket.com, ChemThink, and www.quizevolved.com rely on your support to pay for the cost of their web server.
Great news! “Ions” has been ported from Flash to HTML5. The load lightened just enough at the end of the school year to allow me to finish the port of the Ion Formation tutorial. The new HTML5 version leads students through the formation of positive and negative ions, and should run on any modern browser..
If you have already donated to the site, thank you! As of the time this writing, we are past the halfway mark of our yearly goal of $2500 to keep the site running. If you have not donated yet, please consider donating. www.simbucket.com, ChemThink, and www.quizevolved.com rely on your support to pay for the cost of their web server.
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. www.simbucket.com, ChemThink, and www.quizevolved.com rely on your support to pay for the cost of their web server.
Dear www.simbucket.com and www.quizevolved.com 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 www.simbucket.com and www.quizevolved.com, we are planning an annual donation drive. So far, we have collected the following donations for 2018:
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.
Physics Teacher, NBCT
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 www.tinkercad.com.
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”:
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!