An important concept in physics is simple harmonic motion – the periodic motion of a mass with a restoring force proportinal to its displacement. This force might come from gravity, a spring, or many other sources, but the same mathematics describes their motion. We have many demonstrations of simple harmonic motion (or SHM) in our collection, including G1-01 and G1-52, which you can see in action in this video starring UMD PhD student Subhayan Sayu.
You can experiment with this at home! Any mass on a spring or on a string or rolling in a well can be a pendulum. Or, try out these Periodic Motion simulations at the PhET Collection: Pendulum Lab or Masses and Springs.
The University of Cambridge offers an example of a simple pendulum experiment to try at home; check it out at https://nrich.maths.org/5376
The Flame Tube, or Rubens Tube, is a classic device for showing the wave structure of sound. It was named for German physicist Heinrich Rubens, who developed it around the turn of the last century.
You can see our own flame tube demonstration in action in this video starring Prof. Norbert Linke
The device is, in essence, and oscilloscope without the electronics – it transforms a sound wave into a visible trace by allowing the changes in pressure in the gas in the tube to drive flames to different heights along the top. In this way, you can see that sound does form a wave, and can show a standing wave and measure its wavelength.
To learn more about the Rubens’ Tube, explore these links:
The Lecture Demonstration Facility at the University of Maryland is designed to help faculty spark student interest, identify misconceptions, help students make predictions, facilitate discussion, and reinforce curricular concepts.
We’re often asked how many demonstrations we have in the collection. That’s a more complex question than it might at first seem.
At last count, we have just over 1,500 demonstrations published to the website – that is, that’s how many demonstration pages exist in the collection. But some pages describe a single setup than can be used in several different ways. Take a look at K2-61: Thomson’s Coil, for example. This single page actually describes four different, related demonstrations that can be performed with this device. They don’t require very different equipment to be delivered, just slight changes in preparation, though, and they’re usually all relevant at approximately the same point in a syllabus, so it’s simpler to list them all in one place. Conversely, there are many demonstrations that use the Optical Board – browse through section L and you will see many of them! Since ray optics is divided into several sections in the demonstrations catalog, each of the configurations of the Optical Board is listed separately, to make it easier to find the one you need; and if you’re only doing one demonstration with it, we can configure it for you in advance to save you time in class.
On the other hand, consider M1-12 and H2-22. These are both listings for Interference Transparencies, a popular way to illustrate the interaction of wavefronts. Here, we made the unusual decision to list the same demonstration twice in two different sections, since otherwise someone planning a course on sound might not think to look for relevant demonstrations in the optics section, and vice-versa. These occasional cross-references make it easier to find the demonstrations you need for your class.
And even aside from the demonstration listings as they stand, we’re often called on to combine equipment in unique ways to demonstrate something new! If it’s a combination that’s likely to be repeated or that proves useful to others, it will be added to the website, but we’re generally open to creatively reinterpreting demonstrations to fit a new class context.
Every year we add more demonstrations to the collection; and occasionally a demonstration is retired, if it no longer meets an instructional need or has been superseded by others. So defining just how many demonstrations we have might not be the right question to ask. Ask, rather, what can we demonstrate for you today?
Science is all about data, and our current pandemic is no different.
Be sure to check the UMD COVID-19 Dashboard for the latest campus data and links to reopening plans and proper safety procedures.
In support of most classes moving to an online model this year, the Lecture-Demonstration staff are doing our part to help connect you to resources you need for teaching remotely. As one part of this project, we have begun compiling a Directory of Simulations from around the internet, organized by general area of physics. Find it under the Tools and Resources menu above, or click the image below.
There are a tremendous number of simulations out there, that folks have been creating for years. We’re testing them out, choosing ones that we can confirm currently work (always a question as internet technology marches on) and that seem useful for our department’s classes. As of this posting, we have just over fifty simulations collected. Our initial focus has been on physics that is hard to demonstrate in the classroom, or experiments that are difficult to present as static pictures or live video.
This project is ongoing! As we continue to explore we will be adding more subjects and more demonstrations per subject. We also invite recommendations! If you have a favourite simulation, let us know (email lecdemhelp at physics.umd.edu) so we can check it out and add it to the directory.
We’ll have more new projects posted soon; watch the site for news!
As the COVID-19 pandemic continues, researchers at UMD and around the globe continue to try to better understand the virus and how to treat it.
In our ongoing work to support remote teaching, we are pleased to announce a new resource. Over the summer of 2020, a Teaching Innovation Grant helped to create our new Demonstration Videos. These can be used for remote, hybrid, and in-person classes to present demonstrations in conjunction with class engagement questions.
The Conference for Undergraduate Underrepresented Minorities in Physics returns January 8-10, 2021, and we've gone virtual!
CU2MiP is co-sponsored by UMD Physics and NIST.
Check out the latest blog posts!