what is the different between i5 and i7

Apart from the price, what is the different between i5 and i7? thx

This is a rather complicated question.
Or you can treat i7 is the top series(most powerful donestic cpu for home use) we have on sell market.
i5 is the middle class (the processing power is generally less than i7 series) cpu.
They can be subbranched into different category with respect to design an features.
It is not easy to explain all the details within few sentences.
http://www.diffen.com/difference/i5_vs_i7