54 Technology: Engineering Our World Copyright Goodheart-Willcox Co., Inc. Affordable Good design must be affordable. This means it is available to everyone, regardless of income level. Architects often design beautiful homes for wealthy clients, but others design homes that are both beautiful and affordable. For example, some architects create neighborhoods that mix single-family dwellings with apartments for low-income residents. Colorful residences face sidewalks, paths and playgrounds, making the streets cheerful to look at and providing the community with a safe place for pedestrians and for children to play outside their homes (Figure 3-17). Affordable products can be made using different materials and mass production techniques from those used for higher-end products. For example, hairbrushes come in a wide range of prices. Brushing your hair helps maintain healthy hair and a healthy scalp. Brushing loosens dead skin cells and improves blood circulation to the scalp, thereby improving the movement of oxygen and nutrients to the roots of the hair. The brush in Figure 3-18A is handmade from pure boar bristle and costs over $200. The brush in Figure 3-18B is mass-produced, has nylon bristles, and costs just $8. Environmentally Sustainable and Responsible Every product or service designed by humans has some impact on the environment. The environment can absorb some of this impact. However, the rate at which Earth’s resources are being consumed is unsustainable. It cannot continue this way forever. In addition, the use and disposal of many products and services affects the quality of the environment and the world in which we live. Therefore, environmentally sustainable and responsible design is a priority for the designer. Using materials that grow in nature in the design and manufacture of a product can minimize damage to the environment. These materials will biodegrade once they are discarded. For example, some rapidly growing bamboo species can be harvested one to fi ve years after planting. Matthew Millman Figure 3-17. This housing development provides affordable, well-designed, colorful, safe living spaces for its residents. Brian Rose Chiyacat/Shutterstock.com Figure 3-18. A—Hand-made boar bristle hairbrushes can cost up to $200. B—This mass-produced nylon brush costs $8. A B bjphotographs/Shutterstock.com