Machines and Motion
During the 8 lessons that comprise the Machines and Motion unit, students study the common elements and functions among various simple machines and laws of motion that apply. While they may be familiar with machines, this unit provides the opportunity to consider the true meaning and purpose of machines, their orientation, and how motion impacts them.
In the first few lessons, students use a variety of simple machines to complete the physical work for which the machines are designed. Students analyze a lever and adjust different settings to increase or decrease its strength. They draw conclusions about the function of balance and fulcrum based on discussion and experimentation.
Students investigate to determine the advantage of using a lever. They build a force indicator and compare the force gain of different types of levers. Next, the most important simple machine, the wheel, is introduced. Although students are familiar with wheels, they extend their science understanding by comparing cylinders to wheels and axles and perform an experiment to understand the force of friction. That understanding is extended to determine how wheels help people lift big loads.
In the next set of lessons, speed and motion become the focus. The movement of a car is the springboard for discussion as students learn that an object in motion stays in motion until an opposite force acts upon it. In another activity students become aware that a constant forward motion and speed affect attempts at trying to hit an intended target with a ball. Students investigate the difference between instantaneous speed and average speed as they compute their own walking and running speeds and display their collected data on a graph.
In Lesson 6 students experiment with speed variation and force gain as this relationship applies to various simple machines. The speed/force relationship continues with a focus on ramps. Through experimentation students recognize that the force used to raise an object is r