6 APPLIED SCIENCE 



5. Name the branch of science that explains the reasons for 

 the following: iron rust; expansion of a metal by heat; freezing 

 of water; boiling of water; protection of body by rubber gloves in 

 working around electrical machines; finding lead in the form of 

 sulphides in the earth. 



6. Of what use to a practical man is a knowledge of the physical 

 properties of water? 



7. If the use of a material, such as copper (used in sheet metal 

 tanks and electric wires), is known, is it possible to state its physical 

 properties? 



8. What are the physical properties of high-grade sheet metals? 

 Wire? Copper? Lead? Zinc? 



9. Give the names and uses of some materials that are : porous ; 

 compressible; elastic; soft; hard; heavy; light. 



