To be honest, seventh grade science and I mostly rely on "rote" The magic will be over the five hurdles. However, after entering the eighth grade, this "magic weapon" also lose control of how, and learn it is very practical; thanks to scientific experiments course aroused my interest, leaving me to get into the hands of the teacher is Shen chalk.
To "material density" a class, teacher, Shen, hand chalk told us: "If the quality of chalk Zhezhi 8 grams and measuring 4 cm 3, then its density should be the number?" Students have according to the formula (ρ = m / v) hastened to quickly calculate the density of chalk 2 g / cm 3. Suddenly, Shen teacher "popping" is heard in the hands of broken chalk, told us: "Now, I put chalk randomly divided into two parts, then the density of each part should be the number?" Teacher, Shen, the "casual" This is the word put special emphasis on tone, but also repeated several times. One after another, many students say the answer. "Yes, 2 g / cm 3!" At this time, teacher, Shen, about second-hand grip of varying lengths on the chalk, excitedly said, "because they are chalk!" Since then, the "density of the material properties, the same substance of the plot is unchanged, "this scientific knowledge will be rooted in my heart. Later, we made a determination of the density of matter in group experiments, many students put stones into two, have come to the same or similar density.
Teacher, Shen mentioned formula replicability reasoning using mathematical methods, often with red, yellow and blue chalk in turn show the hands of this teacher, Shen, colored chalk, such as beating of the notes, images, vivid, so that we are both relaxed and learn together happy; Shen teacher also used chalk powder into the suspension liquid foam, and emulsion, the solution can be compared; to chalk on the throw, drop to indicate what is the role of inertial motion and gravity; is to compare chalk down chalk placed on the desktop Pressure Size ... ... In short, each section of each lesson, the teacher's chalk Shen are Magical.
Really magic chalk! When listening to Shen's class, I always felt this way!