Through the hands-on experiences in this unit, my goal is to give students a better awareness of the simple machines that they encounter in everyday life, an understanding of how these machines work, and an appreciation for how they make work easier. Just as importantly, the unit focuses upon how forces act upon objects. I have related the study of simple machines to broad scientific ideas, such as force, gravity, work, pressure, friction, and Newton's laws of motion. The overall movement in the unit is from a discussion of physical concepts, such as force and friction, to an exploration of these ideas through simple machine experiments, and then toward observation and awareness of simple machines in daily life.
I would like my students to be able to follow their own inquiries and think hard about their experiences with the simple machines that they encounter day-to-day. Why doesn't a ball keep rolling and rolling? Why is a weight easier to lift when you change the position of the fulcrum on a lever? How is a toy wagon, or a pair of scissors, a kind of simple machine? The experiments in this unit lend themselves to inquiries and discoveries related to these and many other questions. Through the activities, students are given many opportunities to practice scientific processes, such as developing hypotheses, gathering data, making observations, and trying alternate ideas.
One of my favorite activities when teaching this unit was dropping paint onto newsprint, and comparing the spots at different distances. This experiment gave the students a very visual sense of gravity as a force. Another favorite activity was the students' construction of "puff mobiles," little wheeled carts with sails, an exploration that pulled together many of the physical concepts we had been discussing. Currently, the least developed section is on forces, especially electric force, and I would be interested in your feedback and suggestions for this area.
My approach in this unit has been to particularly rely on collaborative work groups, which can be a challenge at times, depending on the students' abilities to work together. Just as I have structured an inter-personal classroom, I have also tried to personalize the science in various ways, such as bringing humor to it through the use of video-taped programs of "Bill Nye, the Science Guy." The programs are also especially strong for how they relate a vast range of real activity and real people to physical principles. (A list of the stations that air "Bill Nye," as well as a list of program information and lesson plans can be found at http://nyelabs.kcts.org/). In writing the unit, I have included a lot of notes to the teacher that I hope will be helpful, on the science content as well as hints on how to carry out the activities. Please contact me by e-mail should you like further information on the unit, or wish to give feedback.
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