Oersted Medal Lecture 2007: Interactive simulations for teaching physics: What works, what doesn't, and why

We give an overview of the Physics Educational Technology (PhET) project to research and develop web-based interactive simulations for teaching and learning physics. The design philosophy, simulation development and testing process, and range of available simulations are described. The highlights of PhET research on simulation design and effectiveness in a variety of educational settings are provided. This work has shown that a well-designed interactive simulation can be an engaging and effective tool for learning physics

Chemistry vs. Physics: A Comparison of How Biology Majors View Each Discipline

A student's beliefs about science and learning science may be more or less sophisticated depending on the specific science discipline. In this study, we used the physics and chemistry versions of the Colorado Learning Attitudes about Science Survey (CLASS) to measure student beliefs in the large, introductory physics and chemistry courses, respectively. We compare how biology majors -- generally required to take both of the courses -- view these two disciplines. We find that these students' beliefs are more sophisticated about physics (more like the experts in that discipline) than they are about chemistry. At the start of the term, the average % Overall Favorable score on the CLASS is 59% in physics and 53% in chemistry. The students' responses are statistically more expert-like in physics than in chemistry on 10 statements (P lesser-than-or-equal-to 0.01), indicating that these students think chemistry is more about memorizing disconnected pieces of information and sample problems, and has less to do with the real world. In addition, these students' view of chemistry degraded over the course of the term. Their favorable scores shifted -5.7% and -13.5% in 'Overall' and the 'Real World Connection' category, respectively; in the physics course, which used a variety of research-based teaching practices, these scores shifted 0.0% and +0.3%, respectively. The chemistry shifts are comparable to those previously observed in traditional introductory physics courses

Reforming a large lecture modern physics course for engineering majors using a PER-based design

We have reformed a large lecture modern physics course for engineering majors by radically changing both the content and the learning techniques implemented in lecture and homework. Traditionally this course has been taught in a manner similar to the equivalent course for physics majors, focusing on mathematical solutions of abstract problems. Based on interviews with physics and engineering professors, we developed a syllabus and learning goals focused on content that was more useful to our actual student population: engineering majors. The content of this course emphasized reasoning development, model building, and connections to real world applications. In addition we implemented a variety of PER-based learning techniques, including peer instruction, collaborative homework sessions, and interactive simulations. We have assessed the effectiveness of reforms in this course using pre/post surveys on both content and beliefs. We have found significant improvements in both content knowledge and beliefs compared with the same course before implementing these reforms and a corresponding course for physics majors.Comment: To be published in the Proceedings of the Physics Education Research Conference 200

Investigation of low cost, high reliability sealing techniques for hybrid microcircuits, phase 1

A preliminary investigation was made to determine the feasibility of using adhesive package sealing for hybrid microcircuits. Major effort consisted of: (1) surveying representative hybrid manufacturers to assess the current use of adhesives for package sealing; (2) making a cost comparison of metallurgical versus adhesive package sealing; (3) determining the seal integrity of gold plated flatpack type packages sealed with selected adhesives, thermal shock, temperature cycling, mechanical shock, and constant acceleration test environments; and (4) defining a more comprehensive study to continue the evaluation of adhesives for package sealing. Results showed that 1.27 cm square gold plated flatpack type packages sealed with the film adhesives and the paste adhesive retained their seal integrity after all tests, and that similarly prepared 2.54 cm square packages retained their seal integrity after all tests except the 10,000 g's constant acceleration test. It is concluded that these results are encouraging, but by no means sufficient to establish the suitability of adhesives for sealing high reliability hybrid microcircuits

Design guidelines for hybrid microcircuits; organic adhesives for hybrid microcircuits

The properties of organic adhesives were studied to acquire an adequate information base to generate a guideline document for the selection of adhesives for use in high reliability hybrid microcircuits. Specific areas covered include: (1) alternate methods for determining the outgassing of cured adhesives; (2) effects of long term aging at 150C on the electrical properties of conductive adhesives; (3) effects of shelf life age on adhesive characteristics; (4) bond strengths of electrically conductive adhesives on thick film gold metallization, (5) a copper filled adhesive; (6) effects of products outgassed from cured adhesives on device electrical parameters; (7) metal migration from electrically conductive adhesives; and (8) ionic content of electrically insulative adhesives. The tests performed during these investigations are described, and the results obtained are discussed in detail

Development of low cost, high reliability sealing techniques for hybrid microcircuit packages, phase 2

Adhesives were evaluated to determine if they qualify for application to hybrid microcircuit packages. The effort consisted of the following: (1) seal gold-plated Kovar packages with selective adhesives and determine seal integrity after exposure to temperature humidity environments; (2) seal both gold-plated Kovar and ceramic packages with the four best adhesives identified in (1) and determine seal integrity after exposure to MIL-STD-883A test environments; and (3) subject the best adhesive identified in (2) to a 60 C/98% RH environment and determine susceptibility to moisture permeation. Test results are provided

Investigation of organic adhesives for hybrid microcircuits

The properties of organic adhesives were investigated to acquire information for a guideline document regarding the selection of adhesives for use in high reliability hybrid microcircuits. Specifically, investigations were made of (1) alternate methods for determining the outgassing of cured adhesives, (2) effects of long term aging at 150 C on the electrical properties of conductive adhesives, (3) effects of shelf life age on adhesive characteristics, (4) bond strengths of electrically conductive adhesives on thick film gold metallization, (5) a copper filled adhesive, (6) effects of products outgassed from cured adhesives on device electrical parameters, (7) metal migration from electrically conductive adhesives, and (8) ionic content of electrically insulative adhesives. The tests performed during these investigations are described, and the results obtained are discussed

Poor Man's Content Centric Networking (with TCP)

A number of different architectures have been proposed in support of data-oriented or information-centric networking. Besides a similar visions, they share the need for designing a new networking architecture. We present an incrementally deployable approach to content-centric networking based upon TCP. Content-aware senders cooperate with probabilistically operating routers for scalable content delivery (to unmodified clients), effectively supporting opportunistic caching for time-shifted access as well as de-facto synchronous multicast delivery. Our approach is application protocol-independent and provides support beyond HTTP caching or managed CDNs. We present our protocol design along with a Linux-based implementation and some initial feasibility checks

Development of low cost, high reliability sealing techniques for hybrid microcircuit packages. Phase 2, supplement 1: Moisture permeation of adhesive-sealed hybrid microcircuit packages

The susceptibility of adhesive-sealed ceramic packages to moisture permeation was investigated. The two adhesives, Ablebond 789-1 and Epo-Tek H77, were evaluated as package sealants. These adhesives were previously selected as the most promising candidates for this application from a group of ten adhesives. Ceramic packages sealed with these adhesives were exposed to temperature-humidity conditions of 25 C/98 percent RH, 50 C/60 percent RH, 50 C/98 percent RH, and 85 C/85 percent RH and their moisture contents using were monitored solid state moisture sensors sealed inside them. Five packages were tested at each of these exposures - two ceramic packages sealed with each of the two adhesives and one seam-sealed gold-plated Kovar package. This latter package was included to serve as a control. The results showed that the adhesive-sealed packages were not hermetic to moisture. The rates at which moisture entered the packages increased with the severity of the exposure environments (i.e., higher temperatures and higher moisture vapor pressures) with greater dependence on temperature than on moisture vapor pressure