David P. Jackson’s research while affiliated with Dickinson College and other places

We report here two inadvertent errors that appear in our original paper [OSA Continuum 1, 755 (2018)10.1364/OSAC.1.000755].

https://aip-prod-streaming.literatumonline.com/journals/content/ajp/2021/ajp.2021.89.issue-4/10.0002764/20210319/media/10.0002764.mm.original.v1.,2560,965,773,645,.mp4.m3u8?b92b4ad1b4f274c70877518410abb28bf45a6fadfff54c0884ea58110075615c1d5919ea753725730a4097154a835ed714d870fc6d68a93dc52e8a7a4478091a2025ffc58af7d8eac10a5f5e40149d756ab28c65d5572f2b2db44b9faddbd0416f9540de2df1c0a506a828632536e87c6fe106cb8b5be972455080fba8ea3ff1ae8e88cdf774dfcf07cc38e5efc5119c7ad048435b2dd17bc0a116743a715c62406789e3d9b52eadfb1abc9ce8c6 We investigate acoustic levitation in a vertical standing wave in an attempt to understand the basic physical mechanism responsible for this phenomenon. We find that a description in terms of a simple pressure force leads to the prediction of stable equilibria that occur slightly below the anti-nodes of the standing pressure wave. We then demonstrate that such a prediction is at odds with experimental data, which show that levitating particles come to rest slightly below the nodes of the standing pressure wave. Finally, we outline a theoretical approach based on fluid dynamics that correctly predicts the locations of the levitating particles, which leads to a simple qualitative description for this fascinating phenomenon.

Although interactive videos have been feasible for decades, their use in science teaching has increased very slowly until recently. Interactive Video Vignette (IVV) projects in physics and biology have made it easier to create video-based online activities that foster active learning. IVVs produced by the projects have been tested in college-level physics and biology classes, and there is evidence that they promote learning. Materials created by the projects are available online, including finished IVVs and teacher notes, along with Vignette Studio, a user-friendly software application for making IVVs. Vignette Studio can be used to author IVVs that have sophisticated forms of interactivity such as video-based motion analysis and multiple-select branching. A commercial online homework system, WebAssign, has adopted IVVs for physics. This chapter describes the projects as well as some of their products and research results.

Download Original Video (22.7 MB) https://aip-prod-streaming.literatumonline.com/journals/content/ajp/2019/ajp.2019.87.issue-2/1.5086391/20190117/media/1.5086391.mm.original.v1.,2560,965,773,645,.mp4.m3u8?b92b4ad1b4f274c70877518416abb28b88699062dc1e9e1820569d30bc26a8a12b6934d568e0fe0f15bcd5e3cabdf7614fb58276d366790e3a124b73ea1c89f1f37adeeae7f27e1f784ead18f478e257e23bfa33893ac7347ba55f8cb79755a486a3998ed6f2e2f8515be093b65f4420f0817c8d268fff93c7aa92956ab94fb53a171006f8af0cc50cf135ecb35c6ac32baaa9ae27b016c6ce64143b632a39f0bd0c0fad94a935f0beb56064 We explore the steady-state rotational motion of a cylinder on a flat horizontal surface from a pedagogical perspective. We show that the cylinder's inclination angle depends on its rotational velocity in a surprisingly subtle manner, including both stable and unstable solutions as well as a forbidden region with no (real) solutions. Moreover, the cylinder's behavior undergoes a qualitative change as the aspect ratio decreases below a critical value. Using a high-speed video, we measure the inclination angle as a function of rotation speed and demonstrate good agreement with the theoretical predictions. All aspects of the analysis are well within the capabilities of undergraduate students, making this an ideal system to explore in courses or as an independent project.

https://aip-prod-streaming.literatumonline.com/journals/content/ajp/2019/ajp.2019.87.issue-2/1.5086391/20200331/media/1.5086391.mm.original.v1.,2560,965,773,645,.mp4.m3u8?b92b4ad1b4f274c70877518416abb28b88699062dc1e9e1820569d30bc26a8a12b6934d568e0fe0f15bcd5e3cabdf7614fb58276d366790e3a124b73ea1c89f1f37adeeae7f27e1f784ead18f478e257e23bfa33893ac43d08046135f6742436c69ebbc8f501d8737cef772afdc2eb5f73891a43727858d2ff990f01e7ac2d7bf2c31e00f3e04704ca0158e1b7ef06d62d50183cf4f2c17b24d2732051b45c19c62657357fae5a3877c80aa8 We explore the steady-state rotational motion of a cylinder on a flat horizontal surface from a pedagogical perspective. We show that the cylinder's inclination angle depends on its rotational velocity in a surprisingly subtle manner, including both stable and unstable solutions as well as a forbidden region with no (real) solutions. Moreover, the cylinder's behavior undergoes a qualitative change as the aspect ratio decreases below a critical value. Using a high-speed video, we measure the inclination angle as a function of rotation speed and demonstrate good agreement with the theoretical predictions. All aspects of the analysis are well within the capabilities of undergraduate students, making this an ideal system to explore in courses or as an independent project.

https://aip-prod-streaming.literatumonline.com/journals/content/ajp/2019/ajp.2019.87.issue-2/1.5086391/20200331/media/1.5086391.mm.original.v1.,2560,965,773,645,.mp4.m3u8?b92b4ad1b4f274c70877518416abb28b88699062dc1e9e1820569d30bc26a8a12b6934d568e0fe0f15bcd5e3cabdf7614fb58276d366790e3a124b73ea1c89f1f37adeeae7f27e1f784ead18f478e257e23bfa33893ac43d08046135f6742436c69ebbc8f501d8737cef772afdc2eb5f73891a43727858d2ff990f01e7ac2d7bf2c31e00f3e04704ca0158e1b7ef06d62d50183cf4f2c17b24d2732051b45c19c62657357fae5a3874c808ab We explore the steady-state rotational motion of a cylinder on a flat horizontal surface from a pedagogical perspective. We show that the cylinder's inclination angle depends on its rotational velocity in a surprisingly subtle manner, including both stable and unstable solutions as well as a forbidden region with no (real) solutions. Moreover, the cylinder's behavior undergoes a qualitative change as the aspect ratio decreases below a critical value. Using a high-speed video, we measure the inclination angle as a function of rotation speed and demonstrate good agreement with the theoretical predictions. All aspects of the analysis are well within the capabilities of undergraduate students, making this an ideal system to explore in courses or as an independent project.

We provide measurements of Young’s double-slit experiment using a partially-coherent light source consisting of a helium-neon laser incident on a rotating piece of white paper. The data allow a quantitative comparison with both the standard theory that does not account for the width of the slits, and a full, analytic model that does. The data agree much more favorably with the full calculation.

Download Original Video (3.1 MB) https://aip-prod-streaming.literatumonline.com/journals/content/ajp/2018/ajp.2018.86.issue-9/1.5047438/20180823/media/1.5047438.mm.original.v1.,2560,965,773,645,.mp4.m3u8?b92b4ad1b4f274c70877518416abb28b88699062dc1e9e1820569d30bc26a8a12b6934d568e0fe0f15bcd5e3cabdf7614fb58276d266790e5f7e87d73e5f8aeda6561c0732456b93c21fd51448ac2cae29dbcec188cbd48257bcd20324235a2a846c288a251ad01b165ce6c6dbf7e830b0841c5c73c5c2c9c7bceaebe3977e114f9566c01b6e6076fcfc765b05a612801c54f50aedcd9342cd871cb384292955429ec22e1a6ea340cdb5e3d1 We discuss Young's double-slit experiment using a partially coherent light source consisting of a helium-neon laser incident on a rotating piece of white paper. Such an experiment is appropriate for undergraduate students as an independent project or as part of an advanced lab course. As is well known, the resulting interference pattern is observed to disappear and return, depending on the angular size of the source. Interestingly, while the standard theoretical prediction for the light intensity agrees quite well with experimental data when the fringe visibility is high, the prediction is noticeably off when the visibility is low. A first-principles calculation of the light intensity is performed and shown to agree extremely well with the experimental results for all visibilities.