52 Technology: Engineering Our World Copyright Goodheart-Willcox Co., Inc. Ergonomic An essential principle of good design is ergonomics. Ergonomics is the study of how a person, the products used, and the environment (surroundings) can best fi t together. Ergonomics focuses on making products and services effi cient so that fatigue or discomfort is minimized for the user while working. Ergonomists study the interaction between humans and the products they use. They ensure that a product is designed to fi t the user rather than the user having to adapt to fi t the product. Ergonomically effi cient products are user friendly. An ergonomic keyboard for your computer will reduce the risk of repetitive stress injuries (Figure 3-16A). The handle on the chef’s knife designed by Henry Haneda (Figure 3-16B) has an egg-shaped bulge that supports the palm of the hand to reduce stress in the wrist and arm when cutting food. An ergonomic computer workstation reduces the risk of repetitive stress injuries. The chair seat can be adjusted to a comfortable height, with a back that supports the user’s lower back. The height of the table ensures that the keyboard is at a comfortable height and that the user is looking at the screen at the correct angle and distance (Figure 3-16C). To design a product that is ergonomically effi cient, designers use anthropometric data tables. Anthropometry is the science of the measurement of the human body. Anthropometric data tables contain many different measurements of the human body, including height, weight, the width of the palm, the distance between the fi ngertips and elbow, shoulder width, and arm strength. This data is used to design all types of products, from hair dryers to theater seats. Anthropometric data tables are available for different groups of people in different circumstances. For example, data is available for men, women, children, and the elderly different age groups people in standing positions, sitting at computer desks, or reaching to press buttons. This huge range of data illustrates that if you design a product that fi ts only you, it will also only fi t people of a similar size, shape, reach, or strength to you. It also indicates that when designing, you need to know exactly who the users of a product will be. For example, theater seats should be designed so that most people will fi t comfortably. Store shelves are designed with shorter people in mind since, if the shortest person can reach the shelf, then so can everyone else. A B C Corepics VOF/Shutterstock.com Figure 3-16. Examples of ergonomic designs. Henry Haneda Dmitry Melnikov/Shutterstock.com