Introduction to Video Measurement Technology Enhanced Inquiry Based Science Education Introduction to Video Measurement www.cma-science.nl

Video Measurement Allows to make measurements on digital video clips or still images. To analyze motion of real objects on video clips. To analyze shapes of real objects on images. Real-life events can be analyzed in the classroom. www.cma-science.nl

Data collection During measurements: on a video clip the position and time data are collected from points in the selected frames, on an image the position data, (or position and time data for a stroboscopic image), are collected from points in the still image. www.cma-science.nl

Manually or by point tracking The video data points are collected: manually by clicking points of interest in the selected video frames or in an image, automatically by tracking (a point of) a moving object. www.cma-science.nl

Distance and time calibration The coordinate system is placed on the video screen. Distance calibration is made via rulers on the screen. Time information is taken from the frame rate with which the video clip was recorded. www.cma-science.nl

Data display The video data are displayed in a table and in graphs and can be used for further processing. www.cma-science.nl

Bicycle speeding up Motion (position versus time graph) of a bicycle speeding up. www.cma-science.nl

Hitting a softball Motion of a softball hit by a bat (position vs. time and velocity vs. time graphs). Based on the data the impulse of the ball, and the force exerted by the bat on the ball can be calculated. www.cma-science.nl

Yo-yo Motion of a point located on a giant yo-yo. During the measurement the hand of the person holding the yo-yo is moving. Measurement is improved by using the moving co-ordinate system. www.cma-science.nl

Car collision Motion of cars during car collision. The total momentum and kinetic energy of the system can be calculated. www.cma-science.nl

Jump on the Moon Motion of an astronaut jumping on the Moon. The calculated acceleration due to the moon's gravity is 2*-0.796 = -1,592 »-1.6 m/s2. www.cma-science.nl

Rate of chemical reaction Determining the rate of reaction by measuring the volume of produced hydrogen gas via the water level in the cylinder. To indicate the water level lightweight brown balls are used. www.cma-science.nl

Pupil light reflex Recording the pupil motion stimulated by oscillatory light. The pupil diameter changes with the same period of oscillations as the period of the light intensity. www.cma-science.nl

Stroboscopic photographs Motion of free falling ball. Analysis of the stroboscopic photograph with recorded images of the ball at equal time intervals. www.cma-science.nl

Calculating a new video point The measured video points can serve to calculate the location of another video point e.g. the center of mass. The new calculated point is then displayed on the video screen. Useful for studies in motion. www.cma-science.nl

Motion of a high jumper High jump which employs the style known as the Fosbury Flop. Three rigid segments model (biomechanics) is used to calculate the location of the center of mass. The calculated center of mass is going below the bar. www.cma-science.nl

Perspective correction Perspective distortion occurs when the video or image plane is not parallel to lines that are required to be parallel. With help of the Perspective correction option this can be corrected. www.cma-science.nl

Capturing videos Students can capture their own videos. www.cma-science.nl

Even using high-speed cameras High-speed camera enables to do analysis of very fast motions in details. www.cma-science.nl

Educational Benefits Allows to analyze real and attractive events. The events can be rather ordinary, every day events such as basketball shots, soccer kicks, amusement-park rides, plant growth or more unusual like jump on the Moon, car crashes or the motion of a manikin as it strikes an air bag during a car collision. www.cma-science.nl

Educational Benefits Allows to analyze “difficult” experiments. Experiments that are too dangerous or impossible to perform in the classroom. www.cma-science.nl

Educational Benefits Connect real situation with its abstract graphical representation. Graphs are synchronized with the video frames; when scanning the data in the graph the corresponding video frames are shown. This helps to bridge the gap between the concrete visual display and its abstract graphical representation. www.cma-science.nl

Centre for Microcomputer Applications www.cma-science.nl