Question

Give two examples of slow changes.

Answer 1

Hint: As we can understand by the name itself, slow changes are the changes which take a significant amount of time. Slow changes can be chemical, natural or biological too.

Complete-step- by- step answer:
The changes which take a long period of time to happen and do not occur in a minimal span of time are considered as slow changes.
Let us discuss the examples of slow changes-
Slow changes can be physical changes as chemical reactions occur when two reactant mediums are added. But slow changes can be a chemical process too. For example-

1. Rusting of iron- Rusting of iron is a chemical change which takes place in a long period of time. Rust is formed when the iron is exposed to an environment containing moisture. The oxygen present in the environment undergoes a redox reaction with the iron in a water containing environment forming iron oxide which is commonly known as rust. Rust is a mixture of iron oxides formed on iron objects. Formation of rust takes longer time and is not an immediate reaction.
The Fe(III) ions form an insoluble hydroxide which is known as rust-

\[2F{{e}^{3+}}+4{{H}_{2}}O(l)\to F{{e}_{2}}{{O}_{3}}.{{H}_{2}}O(s)+6{{H}^{+}}(aq)\]

Therefore, rusting of iron is an example of slow change where new substance, iron oxide is formed.

2. Another example of slow change is rotation of earth, which causes day to night. It is considered a slow natural change as it is occurring naturally. It is a slow change because it does not occur instantly; it takes 23 hours and 56 minutes. The exact time is known for this change but it might be unknown for other slow changes like ripening of a fruit, drying of a cloth etc.

Note: It is important to remember that slow change refers to the time which is needed for a particular change to take place. It does not necessarily have to be a chemical change.