158 ELEMENTARY GENERAL SCIENCE CHAP. 



10. Describe an experiment to show that water is a bad conductor 

 of heat. 



11. Explain fully the manner in which liquids become heated. 

 Describe some useful application of the facts. 



12. Describe an effective plan for ventilating a dwelling room 

 and point out the principle upon which it depends. 



13. Define what is understood by the melting point of a solid. 

 Explain how you would proceed to determine this temperature in the 

 case of beeswax. 



14. What happens precisely when a liquid boils? What con- 

 nection is there between the boiling point of a liquid and the pres- 

 sure of the atmosphere ? 



15. Give a detailed account of the changes in volume and tem- 

 perature which are noticed as a piece of ice is continuously heated. 



16. What is meant by the latent heat of fusion ? Apply your 

 definition to account for the length of time necessary to effect a 

 complete thaw after a season of frost. 



17. Describe and explain the means adopted to obtain ice in 

 tropical countries. 



18. Why is ice wrapped in flannel in the summer when we want 

 to preserve it ? 



19. If a pound of water at 100 C. is mixed with a pound of water 

 at C ., the temperature of the mixture is 50. How would the 

 result have differed if a pound of oil at 100 C. had been substituted 

 for the hot water ? Explain the difference. 



20. Four ounces of hot lead filings and four ounces of water 

 at the same temperature are poured upon separate slabs of ice. 

 Will the lead or the water melt the most ice ? Give reasons for your 

 answer. 



21. What will be the temperature of the mixture produced by 

 mixing : (a) 1 Ib. of water at C. with 2 Ibs. of water at 90 C. ? 

 (6) 1 Ib. of mercury at 10 C. with 1 Ib. of mercury at 100 C. ? 



22. Water sometimes spurts from the spout of a kettle standing 

 upon a fire. How do you account for this, and how would you 

 prevent it without taking the kettle off the fire ? 



23. What is a thermometer, and what information concerning heat 

 does it supply ? 



Give an instance of each of the following effects produced by 

 heat : (a) change of size, (6) change of temperature, (c) change of 

 state. 



24. Describe a differential air thermometer. How would you use 

 it to investigate whether equal volumes of two different substances 

 give out equal amounts of heat when cooled through the same range 

 of temperature ? 



25. Why is a vessel of water heated more quickly if heat is 

 applied at the bottom than if it is heated at the top ? 



Draw a diagram to illustrate the movements of a liquid heated 

 from below. 



26. Explain exactly how the boiling point of a thermometer is 

 determined. 



27. Point out the difference between the conduction and convection 

 of heat. 



