Question

Observation of Activity 3.1 class 10 science

Answer 1

Answer:

here is your answer

Explanation:

before appearance

• iron. shiny
• copper. rough
• aluminium. shiny
• magnesium dull

after rubbing

• iron shiny than before
• copper. shiny

Answer 2

Answer:

The property of the metal having shinny surface is called metallic luster.

Explanation:

copper, aluminum , iron are reactive metals which react with oxygen in surrounding to  form oxide on the outer layer. As a result metal losses the shiny appearance.

example:

1.Iron forms brown layer called rust.

2.alluminium forms smoke colour  aluminum oxide.

3.copper forms black and green layer with oxygen and Sulphur.

when the metal is rubbed with sandpaper its outer layer is scrapped out. Again the metal becomes shinny.