110 



HOW WE LIGHT OUR HOMES 



lighting units are now 

 classed as direct, indi- 

 rect, or semi-direct. See 

 Figure 165. In choosing 

 one of these types we 

 should keep two impor- 

 tant factors in mind: 

 their efficiency and the 

 nature of the light 

 given off. In direct light- 

 ing at least one half of 

 the light is thrown di- 

 rectly downward to the 

 place where it is used. 

 This is the most effi- 

 cient lighting system because not so much of the light 

 is lost by absorption or diffusion, but it is also the 

 most likely to cause glare which is not good for the 

 eyes. 



In indirect lighting all of the light is reflected up- 

 ward to a light-colored ceiling which gives off a soft 

 diffused light to the room. This is the least economical 



FIG. 166. FOOT-CANDLE METER 



CENTER LIGHTS 



SIDE LIGHTS\PORTABLt LIGHTS 



SMALL ROOM 



MEDIUM ROOM 



LARGE KOOM 



(DIRECT) 



SMALL OK 

 MEDIUM ROOM 



LARGE ROOM 



(GLOBE) 



SMALL OK 

 MEDIUM ROOM 



LARGE. ROOM 



bRIDGE LAMPS 



VANITY LAMPS 



STANDING LAMPS 



TABLE LAMPS 



FIG. 167. DO YOU USE THE PROPER SIZE OF ELECTRIC BULBS 

 IN YOUR HOME? 



This illustration shows the proper number of watts to use for 

 different types of fixtures. Each lamp represents 25 watts. 



lighting system, but it produces the most restful light 

 for the eyes. It is commonly used in hospitals. 



In semi-direct lighting the light passes through a 

 translucent substance which eliminates glare. This 

 method of lighting stands between the other two as 

 to cost and softness of the light produced. 



Illumination experts have recently designed new 

 types of lamps for the home which are said to improve 

 the illumination. In these lamps a reflector made of 

 translucent glass provides a semi-direct light which 

 is soft and restful to the eyes. 



REFERENCES FOR FURTHER STUDY 

 Texts 



Caldwell and Curtis, Science for Today, Chap. 26 



Clement, Collister, and Thurston, Our Surroundings, Chap. 13 



Hunter and Whitman, My Own Science Problems, Unit 6; 



Science in Our World of Progress, Unit 6 ; Science in Our 



Social Life, Unit 6 

 Lake, Harley, and Welton, Exploring the World of Science, 



Chap. 21 

 Pieper and Beauchamp, Everyday Problems in Science, Unit 



15 



Skilling, Tours through the World of Science, Tour 13 

 Van Buskirk and Smith, TKe Science of Everyday Life, Chap. 



8 



Watkins and Bedell, General Science for Today, Chap. 22 

 Webb and Beauchamp, Science by Observation and Experi- 

 ment, Unit 1 (part) 

 Wood and Carpenter, Our Environment: How We Use and 



Control It, Unit 2, Topic 8 



Special references 



Lynde, Physics of the Household 

 Godinez, The Lighting Book 

 Luckiesh, Lighting the Home 



WHAT YOU SHOULD AIM TO ACQUIRE FROM 

 THIS STUDY 



1. A knowledge of the factors which determine the 

 intensity of illumination in a room. 



2. A knowledge of the advantages and disadvantages 

 of direct lighting, semi-direct lighting, and indirect 

 lighting. 



3. An understanding of how artificial light is regulat- 

 ed in our buildings. 



TEST OF MASTERY OF THE TOPIC 



In your notebook complete the statements, answer the 

 questions, and comply with the instructions. 



1. Illumination on any area . . as the distance from the 



light source . 



2. Rough surfaces 



reflected light. 



3. Three general systems of illumination in use at present 



are 



4. Light colored wall paper reflects light _ 

 colored paper. 



5. Describe a direct method of lighting. 



6. Describe an indirect lighting system. 



7. Describe a semi-direct lighting system. 



than dark 



