ice to keep box cool?

you think putting some ice in my box would lower the temps from 90 to 80ish? i was looking at stuff like this... Homemade air conditioner - Instructables

but thought just plan ice in there might work just fine since its a small box(2ft x 2ft x 4ft)

Might have a negative effect on humidity?? There are not any short cuts to ventilation. VV