THE SUN AND HIS FAMILY 



185 



the time required for the Leonids to complete their 

 circuit around the sun. 



Occasionally very large meteors streak across the 

 sky, producing a brilliant phenomenon called a fire- 

 ball. The portions that reach the earth's surface are 

 called meteorites. Thousands of meteorites are now pre- 



American Museum of Natural History 



FIG. 304. THE CAPE YORK METEORITE 



(Weight, 2f>y 2 tons) 



served in museums. One, weighing 36^ tons, found 

 by the late Admiral Peary in Greenland, is now in the 

 American Museum of Natural History in New York 

 City. The largest known meteor, which was found in 

 Mexico, weighs approximately fifty tons. 



Meteorites are roughly divided into three classes : 

 the iron meteorites, composed mainly of iron and 

 nickel ; the stony iron meteorites, in which iron and 

 nickel are mixed with stony materials ; and the stony 

 meteorites, which consist essentially of stony ma- 

 terial with only minor amounts of metals in them. 



REFERENCES FOR FURTHER STUDY 



Texts 



Caldwell and Curtis, Science for Today, Chap. 16 



Clement, Collister, and Thurston, Our Surroundings, Chap. 11 



Hunter and Whitman, Science in Our World of Progress, 



Unit 9 ; Science in Our Social Life, Unit 9 

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



UnitS 

 Pieper and Beauchamp, Everyday Problems in Science, Unit 1 



Powers, Neuner, and Bruner, This Changing World, Chaps. 



2 and 3 ; Man's Control of His Environment, Chap. 32 

 Skilling, Tours through the World of Science, Tour 6 

 Van Buskirk and Smith, The Science of Everyday Life, pp. 



299-301 



Watkins and Bedell, General Science for Today, Chap. 9 

 Webb and Beauchamp, Science by Observation and Experi- 

 ment, Unit 6 



Wood and Carpenter, Our Environment: How We Adapt 

 Ourselves to It, Topics 2 and 3; Our Environment: How 

 We Use and Control It, Topic 14 



Special references 



Collins, The Book of Stars 



Martin, The Friendly Stars 



Lewis, Astronomy for Young Folks 



Proctor, The Young Folk's Book of the Heavens 



MacPherson, The Romance of Modern Astronomy 



WHAT YOU SHOULD AIM TO ACQUIRE FROM 

 THIS STUDY 



1. A knowledge of the nature of our sun, and its 

 relation to other bodies of the solar system. 



2. A knowledge of the planets. 



3. A knowledge of the other members of the solar 

 system : comets, meteors, and asteroids. 



4. Ability to recognize the various visible planets. 



TEST OF MASTERY OF THE TOPIC 



In your notebook complete the statements, answer the 

 questions, and comply with the instructions. 



1. The force which holds the planets in their orbits is 

 called . 



2. The center of our solar system is the . 



3. The planet which most nearly resembles the earth is 



4. "Shooting stars" should be called 



5. If life exists on any other planet, it is probably on 

 or . 



6. The planets in order of their distance from the sun 



are 



7. The planet is closest to the earth. 



8. The smallest planet is 



9. What has science learned of particular interest about 

 the planet Jupiter? 



10. Saturn has rings. The outer ring is about . 



miles in thickness. 



11. Morning and evening stars are in reality 



12. The planet Venus is between the earth and the planet 



. It is (smaller, larger) than the earth. The surface 



of Venus is invisible from the earth because of its 



13. Asteroids are . 



14. Meteors are caused by coming in contact with 



and being heated by the 



15. Explain what a comet is. 



