From 2015 Publication 17 page 208:
Unearned income is generally all income other than salaries, wages, and other amounts received as pay for work actually done. It includes taxable interest, dividends (including capital gain distributions), capital gains, unemployment compensation, taxable scholarship and fellowship grants not reported on Form W-2, the taxable part of social security and pension payments, and certain distributions from trusts. Unearned income includes amounts produced by assets the child obtained with earned income (such as interest on a savings account into which the child deposited wages).
