Activity 3.2 NCERT Class 10 Science, Chapter 3 Metals and Non-metals
Activity 3.2 asks us to cut various metals and note the observation.
When we cut metals, its newly exposed part has a brilliant shine.
Most metals are highly reactive elements. The outer layer of metals reacts with the atmospheric oxygen to form metal oxides. Metal oxides do not have lustrous property. When we cut the metals using a knife its inner unoxidised layer come into view which shines.
This experiment demonstrates metals have shining property. We use the term lustre for the shining property of the metal. So, metals are lustrous.
Application: Metal oxides are a bad conductor of electricity. The oxidation of metals in an electric component may lead to failure. So, we coat metals in circuit with unreactive metals like gold in costly computer parts. It saves them from oxidation.
See also: Rubbing of metals, activity 3.1