Kids at this day and age can not live with out technology. Most of the kids learn better with technology and while playing games.
I am a science teacher but I liked the Mangahigh website. It is for Math, but in my Physics class students who are struggling with the Math concepts can use this effectively to catch on the math skills. I use PHET quite often in my class for virtual labs, as some labs are not possible in the classroom setting and this gives them ways to explore, change the parameters of the lab, etc.
There are lots of free science apps on iPad, popular science, science 360 are few that I will be using.