Infrared Radiography: Modeling X-ray Imaging Without Harmful Radiation

Planar x-ray imaging is a ubiquitous diagnostic tool and is routinely performed to diagnose conditions as varied as bone fractures and pneumonia. The underlying principle is that the varying attenuation coefficients of air, water, tissue, bone, or metal implants within the body result in non-uniform transmission of x-ray radiation. Through the detection of transmitted radiation, the spatial organization and composition of materials in the body can be ascertained. In this paper, we describe an original apparatus that teaches these concepts by utilizing near infrared radiation and an up-converting phosphorescent screen to safely probe the contents of an opaque enclosure

Kinesthetic Activities for the Classroom

Educators have found that kinesthetic involvement in an experiment or demonstration can engage students in a powerful way. With that as our goal, we developed three activities that allow students to connect with and quantitatively explore key physics principles from mechanics with three fun physical challenges. By presenting these activities as competitions, we can challenge students to use what they know about the relevant physics to improve their performance and beat their own score or those of other students. Each activity uses an original, real-time data collecting program that offers students and educators a simple, clear method to demonstrate various physics concepts including: (1) impulse momentum, (2) center of mass (COM), and (3) kinematics. The user interface, written in LabVIEW, is intuitive to operate and only requires Vernier Force Plates, a Vernier LabQuest, a webcam, and acomputer. In this article, we will describe each of these activities, all of which are well suited and readily available for other outreach events or classroom demonstrations

An Easily Assembled Laboratory Exercise in Computed Tomography

In this paper, we present a laboratory activity in computed tomography (CT) primarily composed of a photogate and a rotary motion sensor that can be assembled quickly and partially automates data collection and analysis. We use an enclosure made with a light filter that is largely opaque in the visible spectrum but mostly transparent to the near IR light of the photogate (880 nm) to scan objects hidden from the human eye. This experiment effectively conveys how an image is formed during a CT scan and highlights the important physical and imaging concepts behind CT such as electromagnetic radiation, the interaction of light and matter, artefacts and windowing. Like our setup, previous undergraduate level laboratory activities which teach the basics of CT have also utilized light sources rather than x-rays; however, they required a more extensive setup and used devices not always easily found in undergraduate laboratories. Our setup is easily implemented with equipment found in many teaching laboratories