An Affordable CCD Camera System for Introductory Physics Laboratories

导论物理实验室是大多数大学生体验实验科学基本要素的第一次机会。重要的是，这段经历必须是积极的、有益的。虽然我们目前的大多数实验都很有趣，并且可以教授重要的概念，但学生们经常陷入长时间的数据采集和操作中，他们正确地认为这些活动是“过时的”和“无聊的”。这个项目（物理系为改进入门实验室的教学和设备而进行的为期三年的努力的一部分）旨在将CCD相机和基于486的PC电脑引入实验室，从秋季学期开始进行四个实验。(1)抛射运动。学生们得到一个跳跃的超级球的图像，显示轨迹是抛物线，x和y运动分别是等速和等速加速度。CCD相机和PC使原本费力的数据缩减变得快速而有趣。(2)二维碰撞。通过分析球在空气台上的碰撞和频闪图像来研究线性动量守恒。目前，学生们花1到2个小时拍摄一张照片（宝丽来）并分析数据。CCD/PC系统在几秒钟内获得一张图片，并为学生提供了许多可选的研究-弹性与非弹性，能量守恒，质心运动，变化质量。(3)动能运动（新实验）。空气台上的冰球组成的二维“气体”通过震动墙壁被激发。学生可以测量平均自由程或速度分布。(4)一个可选的实验测量木星卫星的运动。这一提议的目标是开始将介绍性实验室从一步一步的过程转变为一个实验室，在这个实验室中，学生可以使用现代传感器和计算机来探索概念并尝试自己的想法。低成本的高性能CCD摄像系统和基于486的个人计算机使该项目成为可能。

The introductory physics laboratory is the first opportunity for most college students to experience the basic elements of experimental science. It is important that the experience be a positive and rewarding one. Although most of our current experiments are interesting, and can teach important concepts, students frequently get bogged down in lengthy sessions of data taking and manipulation, activities which they correctly regard as "archaic" and "boring." This project (part of a 3-year effort by the Physics department to improve the teaching and equipment in introductory laboratories) seeks to introduce CCD cameras and 486-based PC computers into the lab, starting with four experiments from the fall semester. (1) Projectile Motion. Students get a strobed image of a bouncing superball, showing that the trajectory is a parabola and that the x and y motions are constant speed and constant acceleration, respectively. The CCD camera and PC make the (otherwise laborious) data reduction fast and fun. (2) Two Dimensional Collisions. Pucks collide on an air table and strobed pictures are analyzed to investigate conservation of linear momentum. Currently, students spend 1 to 2 hours getting a picture (Polaroid) and analyzing the data. A CCD/PC system gets a picture in seconds and offers a number of optional studies to the student -- elastic vs. inelastic, energy conservation, center of mass motion, varying mass. (3) Kinetic Motion (a new experiment). A 2-dimensional "gas" of pucks on an air table is excited by shaking walls. Students can measure the mean free path or speed distribution. (4) An optional experiment measures the motions of Jupiter's moons. The goal of this proposal is to begin to move the introductory lab away from step-by-step procedures which lead to an encircled number, toward a lab where students, using modern sensors and computers, can have options to explore concepts and try their own ideas. The project is made feasible by the low costs of highly capable CCD camera systems and 486-based personal computers.