What is the difference between 'je serai' and 'je serais'?

Although both of these sounds the same when spoken out loud, 'je serai' is the first person singlular simple future conjugation of 'etre' - 'to be', (as in 'je serai, tu seras, il/elle/on sera, nous serons, vous serez, ils/elles seront') whereas 'je serais' is the first person singular conditional conjugation of the same verb (as in 'je serais, tu serais, il/elle/on serait, nous serions, vous seriez, ils/elles seraient'.