Lesson 3.3: Corrosion at Work

You are familiar with the corrosion of iron because so many things are made of iron. (Steel is an alloy of iron.) You know how fast some things made of iron rust.  Nice, shiny tools turn into red, useless lumps of iron unless they are properly cared for.  Many metals that corrode also if they are not protected.  Do you know some of these metals? 

Read Corrosion at Work on page 72 in your textbook to learn more about these other metals.

Question 1. What happens to the bright, shiny coins a few years after they are minted?

Question 2: What colour does jewellery and cutlery made of silver turn after a few years?

Question 3: What colour does copper turn after a few years of exposure to the outside air?

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. What happens to the bright, shiny coins a few years after they are minted?

The coins turn dull and discoloured.

Question 2. What colour does jewellery and cutlery made of silver turn after a few years?

Silver turns black when it corrodes, so the jewellery and cutlery will turn black. This process can be quite fast if you live near some industry or petroleum activity.

Question 3. What colour does copper turn after a few years of being exposed to the outside air?

Copper turns green after exposure to the outside air. (Check the colour of the roofs of the parliament buildings in Ottawa; they are made of copper.)

 


Now, do Assignment 4C.  Page forward to access the computer-scored assignment.