HEAVENLY BODIES 489 



10. How many planets the size of Mercury would be required to 

 make a planet as large as the earth? 



11. How many earths would be required to make a planet as 

 large as Jupiter? 



12. What planet has a specific gravity equal to about that 

 of gasoline? 



13. What planet has a specific gravity nearest to the specific 

 gravity of cider vinegar, or maple syrup? 



14. What planet compares with glycerine; what one with dia- 

 mond, in specific gravity? 



15. How long would it take you to cross the ocean if you could 

 travel as fast as Mercury travels through space? 



16. If you can jump 3 feet on the earth, how high a fence would 

 you be able to jump on Mars? 



17. Why does not the sun burn up? 



18. Why does the sun make bodies weigh a great deal more than 

 they do on the earth? 



19. How much would you weigh on the sun? 



20. How does the sun get its heat? 



21. What are some of the superstitions regarding the moon? 



22. How can you tell a new moon from an old moon? 



23. Why do we have a half moon? 



24. What is meant by a full moon? 



25. Which way do the horns of a new moon point^up or down, 

 east or west? 



26. How can you tell by the horns when the moon is an old moon? 



27. What causes the " man " in the moon? 



28. Why does the moon have such a tremendous effect on our 

 tides? 



29. Why do we have higher tides during certain times of the 

 year than at others? 



30. If the water in a pan is made to whirl rapidly why is the 

 central portion lower than the edge of the water? 



31. Why is the earth flattened at the poles? 



32. Why is it necessary to have leap years? 



33. Why do more meteors appear at certain times of the year 

 than at others? 



