Video laboratories: tools for scientific investigation

D ~,ta planning, collection, organization, visualization, and analysis are currently being emphasized as key aspects of the learning process in science and mathematics education. ]Projects that provide students with scientists' and mathematicians' tools--microscopes , calculators, visualization tools, c o m p u t e r s have demonst ra ted that authentic investigatiw. ~ activity can be a supportive context for learning. Recent technological developments make video an exciting and powerful tool for scientific investigation that is both accessible and appeal ing to students. The deve lopment of digitized video and inexpensive video capture boards introduces a new realm of scientific phenomena to the scholastic world. Technical Education Research Centers (TERC), an educational research and. development organization based in Cambridge, Mass., is explor ing the potential of videobased learning. In the Video for Explor ing the World project (VIEW), TERC is developing a product which supports the use of video as a type of laboratory instrument. VIEW provides students with quick access to real-world data such as human and animal motion, the behavior of crowds, flocks, and traffic, and pat terns of growth and decay. Once captured, video phenomena combine the immediacy of real action with the ability to repeat and analyze laboratory experiments. With this use of vide(), students are able to analyze real phenomena, ra ther than abstract models with which they have only an indirect connection. Students can ask and investigate questions such as "How fast is a rope turning dur ing a Double Dutch game?," "What do the arcs of jugg led balls look like?," or "How fast does a hibiscus flower open? Are there times when it is opening more slowly or more quickly?" The significant potential of video laboratories rests on several characteristics of the medium itself as well as on learning activities that combine the power o f video with that of computers. Video's ability to make transient events pe rmanen t means that exper iments can be viewed and analyzed many times. Simple features of video, such as f rame-by-frame viewing and time-lapse taping provide students with the ability both to shrink and to expand time to work with phenomena that would otherwise be unavailable in the classroom. Addit ionally, software can provide measurement instruments that work on video images and simulations that can be overlaid on video. Such a system also has the potential to change students ' relationship to video technology, which they generally experience in a passive way, acting only to switch channels. With VIEW, students see video as an ins t rument with which they can capture the world, make it stand still, speed it up, go back and capture it again, analyze it, and ultimately unders tand it. The VIEW project is based on the success of an earl ier exper iment with a similar approach to educational video. TapeMeasure , designed and built at Bolt Beranek and Newman, made it possible for students to use video to capture and analyze their runn ing styles. A middle school math class in Cambridge, Mass. spent several weeks investigating the variables that might affect students ' runn ing speed. Besides variables such as height and weight, students conside red variables measurable only by using a videotape, such as stride length, stride angle, knee angle, and step frequency. Before doing actual measurements , they fashioned several conjectures to focus their analysis. Many students originally thought that the less someone weighed, the faster that person ran. But Shana, a slightly p lump girl, of fered an opinion that was later re fe r red to as "Shana's con jec tu re" the re was little connection between weight and race time. Alex, a track star, of fered his conjecture that faster runners would have more arm pumps than steps. He based this belief on his coach's advice, who told him that if he moved his arms more quickly, he would be able to run faster. Students then designed their exper iment , deciding how far to run, where to run, and where to place the video camera. Once the videotapes of the exper iments were made, students used a palette of on-screen measurement tools to find out the videodependen t variables. To measure stride length, for example, a s tudent would find a frame where the left foot was on the ground, place a dot at that point on the screen, run the video until the left foot was again on the ground, and measure with a calibra ted ruler the distance between the dot and the final point. (See Figure 1.) Since the data were recorded auto-