What's the difference between 'while' and 'when'?
Nothing is less to be desired than the fate of a young man who, as the Scotch proverb says, in "trying to make a spoon spoils a horn," and becomes a mere hanger-on in literature or in science, when he might have been a useful and a valuable member of Society in other occupations.

Can I use 'while' to replace ' when'?

Question

What's the difference between 'while' and 'when'?
Nothing is less to be desired than  the fate of a young man who, as the Scotch proverb says, in "trying to make a  spoon spoils a horn," and becomes a mere hanger-on in literature or in science, when he might have been a useful and a valuable member of Society in other occupations.

Can I use 'while' to replace ' when'?

Answer

Hi Catherine,

There is a difference in the usage of the two words (when and while). The former (when) is used to give details on the time of an event or action.

Example: Insert a coin when the light comes on. / When the light comes on, insert a coin. 
The time to perform the inserting action is the moment the light comes on.

The latter (while) is used to describing two actions happening at the same time.

Example: While they were boarding the bus, the door closed. 
(Notice that the verb in continuous tense "boarding" is the first action, while the verb in simple past tense "closed" is the second action that interrupted the first action.)

Hope this helps.
Cheers, 
Lance

Answer

No, we only use "while" to show one thing happening at the same time as another thing, which is not what this sentence expresses. For example:

I ate a sandwich while I was waiting.