THE HISTORY of agricultural mechanics is full of stories about

Transcription

1 Physical Science and Mathematics in Agricultural Mechanics THE HISTORY of agricultural mechanics is full of stories about people who discovered a better way to perform a specific task. As we review the historical progress in agricultural mechanics, one observation appears prominent: Agricultural mechanics has always been and continues to be reliant on available technology. The technology of modern agricultural mechanics is based on physical science and mathematics. Technology is becoming more complex, and with the increased complexity is the connection to science. Science is knowledge obtained through a systematic study of the physical and biological world. The use of trial and error to discover new mechanical methods of improving work is being replaced by a sophisticated method of applying science and math to design and construct agricultural machines, structures, and processes. Objective: Explain how agricultural mechanics uses physical science and mathematics to improve efficiency and productivity in agriculture. Key Terms: agricultural mechanics chemistry compound machine earth science machine mathematics mechanical advantage mechanics physical science physics power science simple machine work Page 1 AgEdLibrary.com

2 The Roles of Physical Science and Mathematics in Agricultural Mechanics Mechanics is the study of force on objects that are moving or at rest. Agricultural mechanics is the study of force in agricultural applications. Developing an understanding of basic science principles is important to agricultural mechanics because the science does not change though the task performed often appears different. Pumping ketchup into a bottle uses the same science as pumping grease into a bearing, yet the task appears quite different. Learning how and why a science concept is used in agricultural mechanics is often important in maintenance, construction, design, and repair. Science is repeated often in agricultural mechanics but may have a unique appearance during application. When the history of agricultural mechanics is studied, we find the science has changed very little. We as a society have learned to use science to solve complex agricultural problems. Mathematics is a precise use of numbers. The use of precise measurements and mathematical computation brings detail to agricultural mechanics. Many calculations in agricultural mechanics are used every day, and we often do not recognize their application. Other mathematical calculations are used only for specialized applications. Areas of mathematics used in agricultural mechanics include: Arithmetic the simple manipulation of numbers using addition, subtraction, multiplication, and division. Geometry the branch of mathematics that shows the relationship between angles, lines, points, and surfaces. Agricultural surveying is an example of the use of geometry in agricultural mechanics. Algebra a system for using equations to solve problems. Algebra is a basic mathematical skill for advanced calculations. FIGURE 1. Agricultural surveying requires the use of geometry. (Courtesy, Natural Resources Conservation Service) Trigonometry the branch of mathematics in which calculations are based on the properties of triangles. It often used when other measuring tools cannot provide the precision required. Trigonometry is used in precision agriculture in conjunction with satellites orbiting in space. Calculus an advanced system of calculation that deals with continually changing values. In agricultural mechanics, calculus is used when adjusting aircraft that apply spray mate- Page 2 AgEdLibrary.com

3 rial to crops. It can be used to calculate amounts when the application has multiple variables. Physical science is the study of nonliving material. Factors that define energy and matter are explained using physical science. A key factor in agricultural mechanics is the energy that causes change. Different kinds of energy are used in agricultural mechanics. Energy can be chemical, heat, light, or mechanical. Mechanical energy is sometimes called movement. Physical science can be divided into three categories: chemistry, earth science, and physics. Chemistry is the study of elements and their relationship to each other. Earth science is the study of soil, water, and air. Physics is the study of how energy and matter interact with their application. A very large part of agricultural mechanics is within the area of physics. Physics is divided into smaller categories. The categories of physics include mechanics, heat, light, sound, electricity and magnetism, and electron and nuclear physics. Agricultural mechanics often uses simple machines to do work. Work is the movement of mass over distance. Power should not be confused with work; power incorporates the speed with which the work is achieved. Work does not have a time value, while power measures the work in a given time. A machine is a device that helps people do work. Machines can change the direction of force or increase the amount of force applied to a task. Because no machine is 100 percent efficient, the effort directed into a machine produces a result lower than the input. Machines are classified as simple or compound. A simple machine has only one or two parts. A compound machine is made by combining simple machines to create a machine more complex than its components. Simple machines are grouped into six categories: the inclined plane, the lever, the pulley, the screw, the wedge, and the wheel and axle. Simple machines can multiply the force you apply while sacrificing some portion of the effort. For example, when you use a lever, you can Lever Pulley Inclined plane Screw Wedge Wheel and axle FIGURE 2. These simple machines can multiply the force applies while sacrificing some portion of the effort. Page 3 AgEdLibrary.com

4 FIGURE 3. This combine head is a compound machine. It has an inclined plane (conveyor), wedged (cutter-bar sections), screws (augers), and wheels and axles (cutter-bar wheels and tires). multiply the force but must exchange the extra force for the shorter distance the load can be moved. Simple machines give people the opportunity to apply force much greater than the force they can generate by pure muscle or weight. The increase in force created by simple machines is called mechanical advantage. The science of understanding simple machines and the process of combining simple machines to create compound machines is the science of agricultural mechanics. Summary: Agricultural mechanics is the application of physical science and mathematics. A large portion of agricultural mechanics is focused on how science can improve the efficiency of machines, the operational control of larger machines, and the maintenance and repair of agricultural machines. Using science to improve the machines that produce, process, and transport agricultural commodities has a direct relationship to the time each of us must use to acquire food and fiber for our everyday lives. Agricultural machines are becoming more complex, and yet they require less effort to control through the use of science. Page 4 AgEdLibrary.com

5 Checking Your Knowledge: 1. What is agricultural mechanics? 2. What science principles are used in agricultural mechanics? 3. Why is it important to understand science principles employed in agricultural mechanics? 4. How is the science of mathematics used in agricultural mechanics? 5. Define physical science. 6. Which part of physical science is very commonly used in agricultural mechanics? 7. Describe a simple machine. 8. Describe a compound machine. 9. What is mechanical advantage? Expanding Your Knowledge: 1. Collect examples of simple machines and discuss how they can be combined to create compound machines. Examine a compound machine and list the simple machines it includes. 2. Use science concepts to determine how much force is required to perform simple tasks. Web Links: HowStuffWorks How Does It Work? How Things Work Page 5 AgEdLibrary.com